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Bassin SR, Ferreira De Carvalho J, Gulati M. A Review of Plant-Based Diets for Obesity Management. Endocr Pract 2024:S1530-891X(24)00513-5. [PMID: 38729570 DOI: 10.1016/j.eprac.2024.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/03/2024] [Accepted: 04/29/2024] [Indexed: 05/12/2024]
Abstract
OBJECTIVE Obesity is the most prevalent chronic disease in the United States with over 70% of the American population suffering from overweight/obesity. Recently, the popularity of plant-based diets (PBDs) has grown, with individuals adopting these diets for ethical, health and environmental reasons. Our aim is to evaluate the effect of a PBD on weight loss among patients who are overweight or obese. METHODS A literature review of PBDs for the treatment of obesity was conducted using PubMed and Scopus. Our search yielded 27 intervention trials (3361 participants) and 6 metanalyses (9168 participants, 61 trials). RESULTS Among the intervention trials evaluated, 75% showed a significant decrease in weight loss in the intervention group, on average -5.0 kg (range -1.8 to -12.1 kg). Other outcomes included energy intake (-420 Kcal/d), systolic blood pressure (-3.78 mmHg), fasting plasma glucose (-2.0 mmol/L), hemoglobin A1c (-0.5%, -3.4 mmol/L), total cholesterol (-0.40 mmol/L), low-density lipoprotein (-0.38 mmol/L), triglyceride levels (+0.13 mmol/L), and fiber intake (+10.8 g/d). The 6 meta-analyses showed weight loss (average -2.9 kg, range -2.02 kg to -4.1 kg), body mass index reduction, and improvements in hemoglobin A1c, low-density lipoprotein, and total cholesterol. CONCLUSION PBDs result in significant weight loss and improve metabolic outcomes. PBDs offer a sustainable approach to long-term weight loss maintenance. Health care providers should encourage open discussions with their patients regarding their dietary habits to assist them in setting feasible lifestyle goals and consider shared medical appointments to support patients in transitioning to PBDs.
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Affiliation(s)
- Sandhya Rao Bassin
- Department of Endocrine, Diabetes, and Bone Disease, Icahn School of Medicine at Mount Sinai, New York, New York.
| | | | - Mahima Gulati
- Department of Medical Sciences, Frank H. Netter MD School of Medicine, Quinnipiac University, Hamden, Connecticut
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Samimisedeh P, Afshar EJ, Ejtahed HS, Qorbani M. The impact of vegetarian diet on sperm quality, sex hormone levels and fertility: a systematic review and meta-analysis. J Hum Nutr Diet 2024; 37:57-78. [PMID: 37581238 DOI: 10.1111/jhn.13230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 08/09/2023] [Indexed: 08/16/2023]
Abstract
BACKGROUND An increasing number of people have adhered to a vegetarian diet for several years. Nowadays, the favourable effect of this dietary pattern on metabolic diseases is well established, but its impact on fertility and reproductive health as a serious health concern is not clear yet. Therefore, we aim to summarise existing evidence regarding the possible association between a vegetarian diet and fertility as measured by key indicators such as sperm quality and sex hormone levels. METHODS We systematically searched online databases, including PubMed, ISI, Scopus and Google Scholar, up to 1 December 2022 using relevant keywords. We included observational studies that compared semen quality, sex hormone levels and infertility in people who adhered to a vegetarian diet versus an omnivore diet. Heterogeneity between studies was assessed using I2 and Q tests. Standardised mean differences (SMD) using a random/fixed model were calculated to assess outcomes between vegetarians and omnivores in included articles. RESULTS Finally, out of 972 documents that were retrieved, 20 articles met our inclusion criteria, and 16 were eligible for quantitative synthesis. Results of meta-analyses showed that there were no significant differences between vegetarians and omnivores in terms of semen quality parameters, including total sperm count, total and progressive sperm motility, sperm morphology and sperm concentration. Seven studies on female sex hormone profiles were eligible for meta-analysis. The only significant difference was the lower level of plasma oestrone in vegetarians (pooled SMD: -0.56; 95% confidence interval [CI]: -1.08, -0.05; p-value = 0.03) compared to omnivores. Furthermore, our meta-analysis revealed significantly higher sex-hormone-binding globulin levels in vegetarian men than in omnivores (pooled SMD: 0.52; 95% CI: 0.18, 0.86; p-value = 0.002). CONCLUSION Despite the numerous health benefits of a vegetarian diet, our review suggested that there were no conclusive positive or negative associations between vegetarian diet and semen quality, sex hormone levels and infertility. Further studies are recommended to better understand vegetarian dietary pattern effect on infertility and reproductive health.
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Affiliation(s)
- Parham Samimisedeh
- Cardiovascular Research Center, Alborz University of Medical Sciences, Alborz, Iran
| | - Elmira Jafari Afshar
- Cardiovascular Research Center, Alborz University of Medical Sciences, Alborz, Iran
| | - Hanieh-Sadat Ejtahed
- Obesity and Eating Habits Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mostafa Qorbani
- Non-Communicable Diseases Research Center, Department of Epidemiology and Public Health, Alborz University of Medical Sciences, Karaj, Iran
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Investigating the Effectiveness of Very Low-Calorie Diets and Low-Fat Vegan Diets on Weight and Glycemic Markers in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis. Nutrients 2022; 14:nu14224870. [PMID: 36432557 PMCID: PMC9695880 DOI: 10.3390/nu14224870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/27/2022] [Accepted: 10/29/2022] [Indexed: 11/19/2022] Open
Abstract
Caloric restriction and vegan diets have demonstrated protective effects for diabetes, however their role in improving clinically relevant outcomes has not been summarized. Our aim was to evaluate the evidence for low-calorie diets (VLCD) and vegan diets on weight and glycemic control in the management of patients with Type 2 Diabetes. Database searches were conducted using Cochrane Library, MEDLINE (Ovid) and Embase. Systematic Review Registration: CRD42022310299. Methodological quality of studies was assessed using Cochrane RoB Tool for RCTs, Cochrane ROBINS-I RoB Tool for non-RCTs and NIH Quality Assessment tool for other studies. Sixteen studies with a total of 834 individuals were included and assessed to have a moderate to high risk of bias. Statistically significant changes in weight, BMI, and HbA1c were not observed in vegan diet cohorts. However, LDL cholesterol was significantly decreased by vegan diet. VLCDs significantly improved glycaemic control, with reductions in fasting glucose, pooled mean difference (MD) -1.51 mmol/L (95% CI -2.89, -0.13; p = 0.03; 2 studies) and HbA1c, pooled MD -0.66% (95% CI -1.28, -0.03; p = 0.04; 3 studies) compared to non-dietary therapy. Both diets suggested a trend towards improved weight loss and anthropometric markers vs. control. VLCD diet intervention is associated with improvement in glycaemia control in patients with Type 2 Diabetes.
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Chen P, Zhao Y, Chen Y. A vegan diet improves insulin resistance in individuals with obesity: a systematic review and meta-analysis. Diabetol Metab Syndr 2022; 14:114. [PMID: 35964120 PMCID: PMC9375406 DOI: 10.1186/s13098-022-00879-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND A vegan diet has benefits on weight reduction and on the parameters of glucose and lipid metabolism. This meta-analysis aimed to investigate the efficacy of plant-based diets on insulin resistance and blood lipids in patients with obesity. METHODS PubMed, Embase, and the Cochrane Library were searched for available papers published up to March 2021. The primary outcome was insulin resistance which was assessed by Homeostasis Model Assessment Insulin Resistance (HOMA-IR), other metabolic parameters measures including the pre/post-diet changes in triglycerides, HDL-cholesterol, total cholesterol, LDL-cholesterol. All analyses were performed using the random-effects model. RESULTS Six studies (seven datasets) were included. Compared with baseline, the plant-based diet improved the HOMA-IR (SMD = 1.64, 95%CI 0.95, 2.33; I2 = 91.8%, Pheterogeneity < 0.001), total cholesterol (SMD = 2.51, 95% CI 0.88, 4.13; I2 = 98.0%, Pheterogeneity < 0.001), HDL-cholesterol (SMD = 1.55, 95% CI 0.66, 2.44; I2 = 92.0%, Pheterogeneity < 0.001), and LDL-cholesterol (SMD = 2.50, 95% CI 1.30, 3.70; I2 = 94.4%, Pheterogeneity < 0.001), but not the triglycerides (SMD = - 0.62, 95% CI - 1.92, 0.68; I2 = 97.8%, Pheterogeneity < 0.001). The sensitivity analyses showed that the results were robust. CONCLUSIONS In obese individuals with insulin resistance, a vegan diet improves insulin resistance and dyslipidemia, except for triglycerides.
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Affiliation(s)
- Peng Chen
- Department of Pediatrics, The Second Hospital of Jilin University, Changchun, China
| | - Ying Zhao
- Department of Endocrinology, The Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, China
| | - Yan Chen
- Department of Endocrinology, The Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, China.
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Thomas MS, Puglisi M, Malysheva O, Caudill MA, Sholola M, Cooperstone JL, Fernandez ML. Eggs Improve Plasma Biomarkers in Patients with Metabolic Syndrome Following a Plant-Based Diet-A Randomized Crossover Study. Nutrients 2022; 14:nu14102138. [PMID: 35631279 PMCID: PMC9147178 DOI: 10.3390/nu14102138] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 12/12/2022] Open
Abstract
Plant-based (PB) diets are considered a healthy dietary pattern; however, eggs are not always included in this dietary regime. We hypothesized that the addition of two eggs per day would increase HDL cholesterol as well as plasma lutein, zeaxanthin and choline in individuals with metabolic syndrome (MetS). In this randomized controlled crossover intervention, we recruited 30 participants (49.3 ± 8 y) with MetS who followed a PB diet for 13 weeks. A registered dietitian advised all subjects on food selection and followed them through the intervention to ensure compliance. Participants underwent a 2-week washout with no eggs or spinach (a source of dietary lutein and zeaxanthin) and were randomly allocated to consume spinach (70 g) with either two eggs (EGG) or the equivalent amount of egg substitute (SUB) for breakfast for 4 weeks. After a 3-week washout, they were allocated the alternate breakfast. A total of 24 participants (13 women/11 men) finished the intervention. Plasma lipids, glucose, insulin, anthropometrics, plasma lutein, zeaxanthin, choline and trimethylamine oxide (TMAO) were assessed at baseline and the end of each intervention. When we compared individuals consuming the EGG versus the SUB breakfast, we observed a lower body weight (p < 0.02) and a higher HDL cholesterol (p < 0.025) after the EGG diet. There were no differences in plasma LDL cholesterol, triglycerides, glucose, insulin, or blood pressure. The number of large HDL particles measured by NMR was higher after EGG (p < 0.01) as compared to SUB. Plasma choline was higher in both treatments (p < 0.01) compared to baseline (8.3 ± 2.1 μmol/L). However, plasma choline values were higher in EGG (10.54 ± 2.8 μmol/L) compared to SUB (9.47 ± 2.7 μmol/L) p < 0.025. Both breakfasts increased plasma lutein compared to baseline (p < 0.01), while plasma zeaxanthin was only increased in the egg intervention (p < 0.01). These results indicate that consuming a plant-based diet in combination with whole eggs increases plasma HDL cholesterol, choline and zeaxanthin, important biomarkers in subjects with MetS.
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Affiliation(s)
- Minu S. Thomas
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA; (M.S.T.); (M.P.)
| | - Michael Puglisi
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA; (M.S.T.); (M.P.)
| | - Olga Malysheva
- Department of Human Nutrition, Division of Nutritional Science, Cornell University, Ithaca, NY 14860, USA; (O.M.); (M.A.C.)
| | - Marie A. Caudill
- Department of Human Nutrition, Division of Nutritional Science, Cornell University, Ithaca, NY 14860, USA; (O.M.); (M.A.C.)
| | - Maria Sholola
- Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA; (M.S.); (J.L.C.)
| | - Jessica L. Cooperstone
- Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA; (M.S.); (J.L.C.)
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH 43210, USA
| | - Maria Luz Fernandez
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA; (M.S.T.); (M.P.)
- Correspondence:
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Said T, Khalid A, Takhar K, Srinivasan S, Kaelber KK, Werner JJ. An Update on the Effects of Plant-Based Diets on Cardiometabolic Factors in Adults with Type 2 Diabetes Mellitus. CURRENT CARDIOVASCULAR RISK REPORTS 2022. [DOI: 10.1007/s12170-022-00689-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Szabo Z, Koczka V, Marosvolgyi T, Szabo E, Frank E, Polyak E, Fekete K, Erdelyi A, Verzar Z, Figler M. Possible Biochemical Processes Underlying the Positive Health Effects of Plant-Based Diets-A Narrative Review. Nutrients 2021; 13:nu13082593. [PMID: 34444753 PMCID: PMC8398942 DOI: 10.3390/nu13082593] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/11/2022] Open
Abstract
Plant-based diets are becoming more popular for many reasons, and epidemiological as well as clinical data also suggest that a well-balanced vegan diet can be adopted for the prevention, and in some cases, in the treatment of many diseases. In this narrative review, we provide an overview of the relationships between these diets and various conditions and their potential biochemical background. As whole plant foods are very rich in food-derived antioxidants and other phytochemicals, they have many positive physiological effects on different aspects of health. In the background of the beneficial health effects, several biochemical processes could stand, including the reduced formation of trimethylamine oxide (TMAO) or decreased serum insulin-like growth factor 1 (IGF-1) levels and altered signaling pathways such as mechanistic target of rapamycin (mTOR). In addition, the composition of plant-based diets may play a role in preventing lipotoxicity, avoiding N-glycolylneuraminic acid (Neu5Gc), and reducing foodborne endotoxin intake. In this article, we attempt to draw attention to the growing knowledge about these diets and provide starting points for further research.
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Affiliation(s)
- Zoltan Szabo
- Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary; (E.F.); (E.P.); (Z.V.); (M.F.)
- Correspondence: ; Tel.: +36-72-513-670; Fax: +36-72-513-671
| | - Viktor Koczka
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pecs, 7624 Pecs, Hungary; (V.K.); (E.S.)
- Doctoral School of Health Sciences, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary
| | - Tamas Marosvolgyi
- Institute of Bioanalysis, Medical School, University of Pecs, 7624 Pecs, Hungary;
- Szentagothai Research Center, University of Pecs, 7624 Pecs, Hungary
| | - Eva Szabo
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pecs, 7624 Pecs, Hungary; (V.K.); (E.S.)
| | - Eszter Frank
- Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary; (E.F.); (E.P.); (Z.V.); (M.F.)
| | - Eva Polyak
- Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary; (E.F.); (E.P.); (Z.V.); (M.F.)
| | - Kata Fekete
- Institute for Translational Medicine, Medical School, University of Pecs, 7624 Pecs, Hungary;
| | - Attila Erdelyi
- Institute of Health Insurance, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary;
| | - Zsofia Verzar
- Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary; (E.F.); (E.P.); (Z.V.); (M.F.)
| | - Maria Figler
- Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences, University of Pecs, 7621 Pecs, Hungary; (E.F.); (E.P.); (Z.V.); (M.F.)
- 2nd Department of Internal Medicine and Nephrology Centre, Clinical Centre, University of Pecs, 7624 Pecs, Hungary
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Pollakova D, Andreadi A, Pacifici F, Della-Morte D, Lauro D, Tubili C. The Impact of Vegan Diet in the Prevention and Treatment of Type 2 Diabetes: A Systematic Review. Nutrients 2021; 13:nu13062123. [PMID: 34205679 PMCID: PMC8235036 DOI: 10.3390/nu13062123] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/13/2021] [Accepted: 06/14/2021] [Indexed: 12/19/2022] Open
Abstract
A protective effect of vegan diets on health outcomes has been observed in previous studies, but its impact on diabetes is still debated. The aim of this review is to assess the relationship between vegan diets and the risk for type 2 diabetes (T2D) along with its effect on glycemic control and diabetes-related complications. In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta–Analyses) guidelines, Pubmed and Cochrane library databases were systematically searched for all relevant studies. Seven observational and eight randomized controlled (RCTs) studies were included. The methodological quality of studies was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies and the Cochrane Risk of Bias Tool for RCTs. We found that a vegan diet is associated with lower T2D prevalence or incidence and in T2D patients decreases high glucose values and improves glucose homeostasis, as reported from the majority of included studies. This approach seems to be comparable to other recommended healthful eating models, but as it may have potential adverse effects associated with the long-term exclusion of some nutrients, appropriate nutritional planning and surveillance are recommended, particularly in specific groups of diabetic patients such as frail elderly, adolescents, and pregnant or breastfeeding women.
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Affiliation(s)
- Daniela Pollakova
- Diabetes Unit, San Camillo Forlanini Hospital, Circonvallazione Gianicolense 87, 00152 Rome, Italy;
- Correspondence:
| | - Aikaterini Andreadi
- Department of Systems Medicine, School of Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.A.); (F.P.); (D.D.-M.); (D.L.)
| | - Francesca Pacifici
- Department of Systems Medicine, School of Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.A.); (F.P.); (D.D.-M.); (D.L.)
| | - David Della-Morte
- Department of Systems Medicine, School of Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.A.); (F.P.); (D.D.-M.); (D.L.)
| | - Davide Lauro
- Department of Systems Medicine, School of Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.A.); (F.P.); (D.D.-M.); (D.L.)
- Unit of Endocrinology and Diabetes, University Hospital, Fondazione Policlinico Tor Vergata, Viale Oxford 81, 00133 Rome, Italy
| | - Claudio Tubili
- Diabetes Unit, San Camillo Forlanini Hospital, Circonvallazione Gianicolense 87, 00152 Rome, Italy;
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Jardine MA, Kahleova H, Levin SM, Ali Z, Trapp CB, Barnard ND. Perspective: Plant-Based Eating Pattern for Type 2 Diabetes Prevention and Treatment: Efficacy, Mechanisms, and Practical Considerations. Adv Nutr 2021; 12:2045-2055. [PMID: 34113961 PMCID: PMC8634508 DOI: 10.1093/advances/nmab063] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 02/01/2021] [Accepted: 05/04/2021] [Indexed: 12/14/2022] Open
Abstract
A plant-based eating pattern is associated with a reduced risk of developing type 2 diabetes and is highly effective in its treatment. Diets that emphasize whole grains, vegetables, fruits, and legumes and exclude animal products improve blood glucose concentrations, body weight, plasma lipid concentrations, and blood pressure and play an important role in reducing the risk of cardiovascular and microvascular complications. This article reviews scientific evidence on the effects of plant-based diets for the prevention and treatment of type 2 diabetes. The mechanisms by which plant-based diets improve body weight, insulin sensitivity, and β-cell function are described. Practical considerations including education, nutrition adequacy, and adjusting medications will enhance the success of patients who have diabetes.
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Affiliation(s)
| | - Hana Kahleova
- Department of Clinical Research, Physicians Committee for Responsible Medicine, Washington, DC, USA
| | - Susan M Levin
- Department of Nutrition, Physicians Committee for Responsible Medicine, Washington, DC, USA
| | - Zeeshan Ali
- Department of Nutrition, Physicians Committee for Responsible Medicine, Washington, DC, USA
| | - Caroline B Trapp
- Department of Nutrition, Physicians Committee for Responsible Medicine, Washington, DC, USA
| | - Neal D Barnard
- Department of Nutrition, Physicians Committee for Responsible Medicine, Washington, DC, USA
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Kahleova H, Petersen KF, Shulman GI, Alwarith J, Rembert E, Tura A, Hill M, Holubkov R, Barnard ND. Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial. JAMA Netw Open 2020; 3:e2025454. [PMID: 33252690 PMCID: PMC7705596 DOI: 10.1001/jamanetworkopen.2020.25454] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
IMPORTANCE Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions. OBJECTIVE To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults. DESIGN, SETTING, AND PARTICIPANTS This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone. INTERVENTIONS Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks. MAIN OUTCOMES AND MEASURES At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis. RESULTS Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (-1.3; 95% CI, -2.2 to -0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = -0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01). CONCLUSIONS AND RELEVANCE A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02939638.
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Affiliation(s)
- Hana Kahleova
- Physicians Committee for Responsible Medicine, Washington, DC
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut
- Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Jihad Alwarith
- Physicians Committee for Responsible Medicine, Washington, DC
| | - Emilie Rembert
- Physicians Committee for Responsible Medicine, Washington, DC
| | - Andrea Tura
- Metabolic Unit, CNR Institute of Neuroscience, Padua, Italy
| | - Martin Hill
- Institute of Endocrinology, Prague, Czech Republic
| | | | - Neal D. Barnard
- Physicians Committee for Responsible Medicine, Washington, DC
- George Washington University School of Medicine and Health Sciences, Washington, DC
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Vučić Lovrenčić M, Gerić M, Košuta I, Dragičević M, Garaj-Vrhovac V, Gajski G. Sex-specific effects of vegetarian diet on adiponectin levels and insulin sensitivity in healthy non-obese individuals. Nutrition 2020; 79-80:110862. [PMID: 32711387 DOI: 10.1016/j.nut.2020.110862] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/15/2020] [Accepted: 04/13/2020] [Indexed: 02/01/2023]
Abstract
OBJECTIVES The beneficial influence of a vegetarian diet in reducing the risk for metabolic syndrome has been demonstrated. However, adiponectin production and secretion are scarcely studied in vegetarians, despite their important role in recovering metabolic homeostasis by reducing visceral obesity, inflammation, and insulin resistance. The aim of this study was to evaluate the effect of a vegetarian diet on serum adiponectin levels and its association with the established biomarkers of insulin sensitivity and inflammation in healthy, non-obese individuals. METHODS Adiponectin, C-reactive protein, uric acid, glucose, insulin, lymphocyte and polymorphonuclear cell counts were determined in the blood of sex- and age-matched healthy vegetarian (n = 40) and omnivore (n = 36) individuals. The homeostatic model assessment (HOMA-2) calculator was used for the β-cell function (HOMA2-%B) and insulin resistance index (HOMA2-IRI) estimation. RESULTS Adiponectin levels were significantly higher in female vegetarians than the respective omnivore controls (P = 0.03), whereas no dietary-associated difference was observed in men. HOMA2-%B was significantly higher in vegetarians than in omnivore controls (P = 0.04), whereas no diet-dependent differences were found in insulin, HOMA2-IRI, inflammatory, and metabolic biomarkers. Multiple regression analysis showed that adiponectin levels were significantly predicted by the type of diet only in women (P = 0.042), whereas no associations were found in men. CONCLUSIONS A vegetarian diet resulted in improved β-cell function. Favorable adiponectin and insulin sensitivity responses in women reveal a distinct effect of diet-to-metabolic homeostasis, indicating an interesting pattern of sexual dimorphism regarding the beneficial metabolic effect of a vegetarian diet.
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Affiliation(s)
- Marijana Vučić Lovrenčić
- Department of Clinical Chemistry and Laboratory Medicine, Merkur University Hospital, Zagreb, Croatia
| | - Marko Gerić
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Iva Košuta
- Department of Internal Medicine, University Hospital Center, Zagreb, Croatia
| | - Maro Dragičević
- Department of Internal Medicine, Merkur University Hospital, Zagreb, Croatia
| | - Vera Garaj-Vrhovac
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Goran Gajski
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia.
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12
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Radnitz C, Ni J, Dennis D, Cerrito B. <p>Health Benefits of a Vegan Diet: Current Insights</p>. NUTRITION AND DIETARY SUPPLEMENTS 2020. [DOI: 10.2147/nds.s191793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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13
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de Carvalho GB, Dias-Vasconcelos NL, Santos RKF, Brandão-Lima PN, da Silva DG, Pires LV. Effect of different dietary patterns on glycemic control in individuals with type 2 diabetes mellitus: A systematic review. Crit Rev Food Sci Nutr 2019; 60:1999-2010. [PMID: 31204492 DOI: 10.1080/10408398.2019.1624498] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Different dietary patterns have been positively related to the glycemic control of individuals with type 2 diabetes mellitus. However, consensual dietary pattern for these individuals is not established. We aimed to evaluate the effects of adopting different dietary patterns on glycemic control markers of individuals with type 2 diabetes mellitus. PubMed, Scopus, MEDLINE, Lilacs, Open Thesis and Google Scholar databases were searched using the Medical Subject Headings and terms related to dietary pattern and glycemic control in individuals with type 2 diabetes mellitus. Interventional studies with adults of this population without diabetes-related complications, presenting data on percentage of glycated hemoglobin, and dietary patterns were included. In vitro, animal, reviews, observational, and studies with children, adolescents, pregnant and breastfeeding women were excluded. The time of adoption dietary patterns ranged from eight weeks to four years in randomized clinical trials, and six months in the cohort study. Vegetarian, vegan, Mediterranean, and Dietary Approaches to Stop Hypertension dietary patterns reduced 0.8% on average of percentage of glycated hemoglobin, considering all included studies. It was also observed reduction in fasting glycemia and improvement in Homeostasis Model Assessment of Insulin Sensitivity. However, more randomized clinical trials are required for a full elucidation of these questions.
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Affiliation(s)
| | | | | | | | - Danielle Góes da Silva
- Postgraduate Program in Nutrition Sciences, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
- Department of Nutrition, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
| | - Liliane Viana Pires
- Postgraduate Program in Nutrition Sciences, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
- Department of Nutrition, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
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Picasso MC, Lo-Tayraco JA, Ramos-Villanueva JM, Pasupuleti V, Hernandez AV. Effect of vegetarian diets on the presentation of metabolic syndrome or its components: A systematic review and meta-analysis. Clin Nutr 2019; 38:1117-1132. [PMID: 29907356 DOI: 10.1016/j.clnu.2018.05.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/16/2018] [Accepted: 05/29/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Several studies have examined the effect of vegetarian diets (VD) on metabolic syndrome (MetS) or its components, but findings have been inconsistent. The aim of this study was to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies to assess the association between VD and MetS or its components (systolic blood pressure [SBP], diastolic blood pressure [DBP], fasting glucose triglycerides, waist circumference [WC], HDL-cholesterol (HDL-C)) in adults. METHODS The Cochrane Library, EMBASE, PubMed, Web of Science, and Scopus were searched. RCTs, cohort studies and cross-sectional studies evaluating the effects of VD on MetS or its components in adults, with omnivore diet as control group, were included. Random effects meta-analyses stratified by study design were employed to calculate pooled estimates. RESULTS A total of 71 studies (n = 103 008) met the inclusion criteria (6 RCTs, 2 cohorts, 63 cross-sectional). VD were not associated with MetS in comparison to omnivorous diet (OR 0.96, 95% CI 0.50-1.85, p = 0.9) according to meta-analysis of five cross-sectional studies. Likewise, meta-analysis of RCTs and cohort studies indicated that consumption of VD were not associated with MetS components. Meta-analysis of cross-sectional studies demonstrated that VD were significantly associated with lower levels of SBP (mean difference [MD] -4.18 mmHg, 95%CI -5.57 to -2.80, p < 0.00001), DBP (MD -3.03 mmHg, 95% CI -4.93 to -1.13, p = 0.002), fasting glucose (MD -0.26 mmol/L, 95% CI -0.35to -0.17, p < 0.00001), WC (MD -1.63 cm, 95% CI -3.13 to -0.13, p = 0.03), and HDL-C (MD -0.05 mmol/L, 95% CI -0.07 to -0.03, p < 0.0001) in comparison to omnivorous diet. Heterogeneity of effects among cross-sectional studies was high. About, one-half of the included studies had high risk of bias. CONCLUSIONS VD in comparison with omnivorous diet is not associated with a lower risk of MetS based on results of meta-analysis of cross-sectional studies. The association between VD and lower levels of SBP, DBP, HDL-C, and fasting glucose is uncertain due to high heterogeneity across the cross-sectional studies. Larger and controlled studies are needed to evaluate the association between VD and MetS and its components.
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Affiliation(s)
- Maria C Picasso
- School of Nutrition, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru.
| | - Jessica A Lo-Tayraco
- School of Nutrition, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru.
| | - Juselly M Ramos-Villanueva
- School of Nutrition, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru.
| | | | - Adrian V Hernandez
- School of Medicine, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru; University of Connecticut/Hartford Hospital Evidence-based Practice Center, Hartford, CT 06102, USA.
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15
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Cui X, Wang B, Wu Y, Xie L, Xun P, Tang Q, Cai W, Shen X. Vegetarians have a lower fasting insulin level and higher insulin sensitivity than matched omnivores: A cross-sectional study. Nutr Metab Cardiovasc Dis 2019; 29:467-473. [PMID: 30956029 DOI: 10.1016/j.numecd.2019.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 12/29/2018] [Accepted: 01/24/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND AND AIMS Potential associations of vegetarian diet patterns with fasting insulin (FI) and insulin sensitivity remain unclear. We aimed to investigate whether vegetarian diets were associated with FI and insulin sensitivity in a cross-sectional study in Chinese vegetarians and matched omnivores and then to test whether it is independent of body mass index (BMI). METHODS AND RESULTS This study included 279 vegetarians (73 vegans, 206 lacto-ovo-vegetarians) and 279 age- and sex-matched omnivores. Fasting blood glucose (FG) and FI concentrations were measured, and β-cell function (HOMA-β) and insulin resistance index (HOMA-IR) were used to evaluate insulin sensitivity. All blood glucose and insulin sensitivity indices were naturally log-transformed, and multiple-linear regression was used to determine the association between vegetarian diet patterns and insulin sensitivity after adjusting for confounders including BMI, visceral fat area, physical activity, sedentary time, income, alcohol consumption, and daily dietary intakes of macronutrients. Compared to omnivores, both vegan diet [β = -0.25, 95% CI: (-0.38, -0.14)] and lacto-ovo-vegetarian diet [β = -0.10, 95% CI: (-0.18, -0.01)] were negatively associated with HOMA-IR after adjusting for BMI. Vegan diet remained negatively associated with FI [β = -0.16, 95% CI: (-0.30, -0.01)] and HOMA-IR [β = -0.17, 95% CI: (-0.32, -0.03)] after adjusting for all confounders. CONCLUSION Vegetarian diet, especially vegan diet, is negatively associated with FI and IR, independent of BMI.
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Affiliation(s)
- X Cui
- Department of Nutrition, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China
| | - B Wang
- Department of Nutrition, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Y Wu
- Department of Nutrition, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China
| | - L Xie
- Department of Nutrition, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China
| | - P Xun
- Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, IN 47405, USA
| | - Q Tang
- Department of Clinical Nutrition, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - W Cai
- Department of Nutrition, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China; Department of Clinical Nutrition, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
| | - X Shen
- Department of Nutrition, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China; Department of Clinical Nutrition, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
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16
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Benatar JR, Stewart RAH. Cardiometabolic risk factors in vegans; A meta-analysis of observational studies. PLoS One 2018; 13:e0209086. [PMID: 30571724 PMCID: PMC6301673 DOI: 10.1371/journal.pone.0209086] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/29/2018] [Indexed: 02/07/2023] Open
Abstract
Background There is increasing evidence that plant based diets are associated with lower cardiovascular risk. Objective To evaluate effects of a vegan compared to an omnivorous diet on cardio-metabolic risk factors. Methods Meta-analysis of observational studies published between 1960 and June 2018 that reported one or more cardio-metabolic risk factors in vegans and controls eating an omnivorous diet were undertaken. Macro-nutrient intake and cardio-metabolic risk factors were compared by dietary pattern. The Newcastle Ottawa Scale (NOS) was used to assess the quality of each study. The inverse-variance method was used to pool mean differences. Statistical analyses were performed using RevMan software version 5•2 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen. Results 40 studies with 12 619 vegans and 179 630 omnivores were included. From food frequency questionnaires in 28 studies, vegans compared to omnivores consumed less energy (-11%, 95% confidence interval -14 to -8) and less saturated fat (- 51%, CI -57 to -45). Compared to controls vegans had a lower body mass index (-1.72 kg/m2, CI -2.30 to -1.16), waist circumference (-2.35 cm, CI -3.93 to -0.76), low density lipoprotein cholesterol (-0.49 mmol/L CI -0.62 to -0.36), triglycerides (-0.14 mmol/L, CI -0.24 to -0.05), fasting blood glucose (-0.23 mmol/, CI -0.35 to -0.10), and systolic (-2.56 mmHg, CI -4.66 to -0.45) and diastolic blood pressure (-1.33 mmHg, CI -2.67 to -0.02), p<0.0001 for all. Results were consistent for studies with < and ≥ 50 vegans, and published before and after 2010. However in several large studies from Taiwan a vegan diet was not associated with favourable cardio-metabolic risk factors compared to the control diets. Conclusion In most countries a vegan diet is associated with a more favourable cardio- metabolic profile compared to an omnivorous diet.
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Affiliation(s)
- Jocelyne R. Benatar
- Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand
- * E-mail:
| | - Ralph A. H. Stewart
- Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand
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17
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Yokoyama Y, Levin SM, Barnard ND. Association between plant-based diets and plasma lipids: a systematic review and meta-analysis. Nutr Rev 2018; 75:683-698. [PMID: 28938794 PMCID: PMC5914369 DOI: 10.1093/nutrit/nux030] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Context Although a recent meta-analysis of randomized controlled trials showed that adoption of a vegetarian diet reduces plasma lipids, the association between vegetarian diets and long-term effects on plasma lipids has not been subjected to meta-analysis. Objective The aim was to conduct a systematic review and meta-analysis of observational studies and clinical trials that have examined associations between plant-based diets and plasma lipids. Data Sources MEDLINE, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for articles published in English until June 2015. Study Selection The literature was searched for controlled trials and observational studies that investigated the effects of at least 4 weeks of a vegetarian diet on plasma lipids. Data Extraction Two reviewers independently extracted the study methodology and sample size, the baseline characteristics of the study population, and the concentrations and variance measures of plasma lipids. Mean differences in concentrations of plasma lipids between vegetarian and comparison diet groups were calculated. Data were pooled using a random-effects model. Results Of the 8385 studies identified, 30 observational studies and 19 clinical trials met the inclusion criteria (N = 1484; mean age, 48.6 years). Consumption of vegetarian diets was associated with lower mean concentrations of total cholesterol (−29.2 and −12.5 mg/dL, P < 0.001), low-density lipoprotein cholesterol (−22.9 and −12.2 mg/dL, P < 0.001), and high-density lipoprotein cholesterol (−3.6 and −3.4 mg/dL, P < 0.001), compared with consumption of omnivorous diets in observational studies and clinical trials, respectively. Triglyceride differences were −6.5 (P = 0.092) in observational studies and 5.8 mg/dL (P = 0.090) in intervention trials. Conclusions Plant-based diets are associated with decreased total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol, but not with decreased triglycerides. Systematic Review Registration PROSPERO number CRD42015023783. Available at: https://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015023783.
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Affiliation(s)
- Yoko Yokoyama
- Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa, Japan
| | - Susan M Levin
- Physicians Committee for Responsible Medicine, Washington, DC, USA
| | - Neal D Barnard
- Physicians Committee for Responsible Medicine, Washington, DC, USA.,School of Medicine and Health Sciences, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
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18
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Plant-Based Nutrition: An Essential Component of Cardiovascular Disease Prevention and Management. Curr Cardiol Rep 2017; 19:104. [DOI: 10.1007/s11886-017-0909-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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19
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Adherence to a Vegetarian Diet and Diabetes Risk: A Systematic Review and Meta-Analysis of Observational Studies. Nutrients 2017; 9:nu9060603. [PMID: 28613258 PMCID: PMC5490582 DOI: 10.3390/nu9060603] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/07/2017] [Accepted: 06/10/2017] [Indexed: 12/31/2022] Open
Abstract
We quantitatively assessed the association between a vegetarian diet and diabetes risk using pooled estimates from observational studies. Electronic database searches for articles published from January 1980 to May 2016 were independently performed by two investigators, and 13 articles (14 studies) were identified. The pooled odds ratio (OR) for diabetes in vegetarians vs. non-vegetarians was 0.726 (95% confidence interval (CI): 0.608, 0.867). In the subgroup analyses, this inverse association was stronger for the studies conducted in the Western Pacific region (OR 0.514, 95% CI: 0.304, 0.871) and Europe/North America (OR 0.756, 95% CI: 0.589, 0.971) than studies conducted in Southeast Asia (OR 0.888, 95% CI: 0.718, 1.099). No study had a substantial effect on the pooled effect size in the influence analysis, and the Egger's (p = 0.465) and Begg's tests (p = 0.584) revealed no publication bias. This meta-analysis indicates that a vegetarian diet is inversely associated with diabetes risk. Our results support the need for further investigations into the effects of the motivations for vegetarianism, the duration of the adherence to a vegetarian diet, and type of vegetarian on diabetes risk.
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Kahleova H, Klementova M, Herynek V, Skoch A, Herynek S, Hill M, Mari A, Pelikanova T. The Effect of a Vegetarian vs Conventional Hypocaloric Diabetic Diet on Thigh Adipose Tissue Distribution in Subjects with Type 2 Diabetes: A Randomized Study. J Am Coll Nutr 2017; 36:364-369. [DOI: 10.1080/07315724.2017.1302367] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hana Kahleova
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
- Physicians Committee for Responsible Medicine, Washington, DC
| | - Marta Klementova
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Vit Herynek
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Antonin Skoch
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Stepan Herynek
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Martin Hill
- Institute of Endocrinology, Prague, Czech Republic
| | - Andrea Mari
- C.N.R. (National Research Council) Institute of Neuroscience, Padua, Italy
| | - Terezie Pelikanova
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Jaceldo-Siegl K, Lütjohann D, Sirirat R, Mashchak A, Fraser GE, Haddad E. Variations in dietary intake and plasma concentrations of plant sterols across plant-based diets among North American adults. Mol Nutr Food Res 2017; 61. [PMID: 28130879 DOI: 10.1002/mnfr.201600828] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/18/2017] [Accepted: 01/19/2017] [Indexed: 01/13/2023]
Abstract
SCOPE Phytosterols are bioactive compounds in plants with similar cholesterol-lowering properties as vegetarian diets. However, information on phytosterol intake and plasma plant sterols among vegetarians is sparse. METHODS AND RESULTS We examined dietary intake and plasma concentration of plant sterols and cholesterol across five dietary patterns in the Adventist Health Study-2 Calibration Sub-study (n = 861, 66% females, average age 61 years). To measure intake and plasma concentrations of these compounds, we used 24-h dietary recalls and gas-liquid chromatography-flame ionization detection, respectively. Mean (SD) total phytosterol and cholesterol intake were 363 (176) mg/day and 131 (111) mg/day; plasma β-sitosterol, campesterol, and cholesterol were 3.3 (1.7) μg/mL, 4.2 (2.3) μg/mL, and 1.9 (0.4) mg/mL, respectively. Total phytosterol intake was lowest among non-vegetarians (263 mg/day) and highest among vegans (428 mg/day) (p < 0.0001). Cholesterol intake was lowest among vegans (15.2 mg/day) and highest among non-vegetarians (124.6 mg/day) (p < 0.0001). Plasma plant sterols and cholesterol did not differ by diet. Cholesterol-adjusted plasma β-sitosterol and campesterol were significantly higher in Blacks than Whites, though no ethnic differences were observed in dietary intake of these plant sterols. CONCLUSION Dietary intake but not plasma concentration of plant sterols and cholesterol varies across distinct plant-based diets.
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Affiliation(s)
- Karen Jaceldo-Siegl
- Adventist Health Studies, School of Public Health, Loma Linda University, Loma Linda, CA, USA
| | - Dieter Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Bonn
| | - Rawiwan Sirirat
- Adventist Health Studies, School of Public Health, Loma Linda University, Loma Linda, CA, USA
| | - Andrew Mashchak
- Adventist Health Studies, School of Public Health, Loma Linda University, Loma Linda, CA, USA
| | - Gary E Fraser
- Adventist Health Studies, School of Public Health, Loma Linda University, Loma Linda, CA, USA
| | - Ella Haddad
- Adventist Health Studies, School of Public Health, Loma Linda University, Loma Linda, CA, USA
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Veleba J, Matoulek M, Hill M, Pelikanova T, Kahleova H. "A Vegetarian vs. Conventional Hypocaloric Diet: The Effect on Physical Fitness in Response to Aerobic Exercise in Patients with Type 2 Diabetes." A Parallel Randomized Study. Nutrients 2016; 8:nu8110671. [PMID: 27792174 PMCID: PMC5133059 DOI: 10.3390/nu8110671] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/06/2016] [Accepted: 10/17/2016] [Indexed: 11/24/2022] Open
Abstract
It has been shown that it is possible to modify macronutrient oxidation, physical fitness and resting energy expenditure (REE) by changes in diet composition. Furthermore, mitochondrial oxidation can be significantly increased by a diet with a low glycemic index. The purpose of our trial was to compare the effects of a vegetarian (V) and conventional diet (C) with the same caloric restriction (−500 kcal/day) on physical fitness and REE after 12 weeks of diet plus aerobic exercise in 74 patients with type 2 diabetes (T2D). An open, parallel, randomized study design was used. All meals were provided for the whole study duration. An individualized exercise program was prescribed to the participants and was conducted under supervision. Physical fitness was measured by spiroergometry and indirect calorimetry was performed at the start and after 12 weeks Repeated-measures ANOVA (Analysis of variance) models with between-subject (group) and within-subject (time) factors and interactions were used for evaluation of the relationships between continuous variables and factors. Maximal oxygen consumption (VO2max) increased by 12% in vegetarian group (V) (F = 13.1, p < 0.001, partial η2 = 0.171), whereas no significant change was observed in C (F = 0.7, p = 0.667; group × time F = 9.3, p = 0.004, partial η2 = 0.209). Maximal performance (Watt max) increased by 21% in V (F = 8.3, p < 0.001, partial η2 = 0.192), whereas it did not change in C (F = 1.0, p = 0.334; group × time F = 4.2, p = 0.048, partial η2 = 0.116). Our results indicate that V leads more effectively to improvement in physical fitness than C after aerobic exercise program.
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Affiliation(s)
- Jiri Veleba
- Institute for Clinical and Experimental Medicine, Videnska 1958/9, 14021 Prague, Czech Republic.
| | - Martin Matoulek
- General University Hospital, 3rd Internal Clinic of Endocrinology and Metabolism, 12808 Prague, Czech Republic.
| | - Martin Hill
- Institute of Endocrinology, Narodni 8, 11394 Prague, Czech Republic.
| | - Terezie Pelikanova
- Institute for Clinical and Experimental Medicine, Videnska 1958/9, 14021 Prague, Czech Republic.
| | - Hana Kahleova
- Institute for Clinical and Experimental Medicine, Videnska 1958/9, 14021 Prague, Czech Republic.
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Lee YM, Kim SA, Lee IK, Kim JG, Park KG, Jeong JY, Jeon JH, Shin JY, Lee DH. Effect of a Brown Rice Based Vegan Diet and Conventional Diabetic Diet on Glycemic Control of Patients with Type 2 Diabetes: A 12-Week Randomized Clinical Trial. PLoS One 2016; 11:e0155918. [PMID: 27253526 PMCID: PMC4890770 DOI: 10.1371/journal.pone.0155918] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/05/2016] [Indexed: 01/19/2023] Open
Abstract
Objective Several intervention studies have suggested that vegetarian or vegan diets have clinical benefits, particularly in terms of glycemic control, in patients with type 2 diabetes (T2D); however, no randomized controlled trial has been conducted in Asians who more commonly depend on plant-based foods, as compared to Western populations. Here, we aimed to compare the effect of a vegan diet and conventional diabetic diet on glycemic control among Korean individuals. Materials and Methods Participants diagnosed with T2D were randomly assigned to follow either a vegan diet (excluding animal-based food including fish; n = 46) or a conventional diet recommended by the Korean Diabetes Association 2011 (n = 47) for 12 weeks. HbA1c levels were measured at weeks 0, 4, and 12, and the primary study endpoint was the change in HbA1c levels over 12 weeks. Results The mean HbA1c levels at weeks 0, 4, and 12 were 7.7%, 7.2%, and 7.1% in the vegan group, and 7.4%, 7.2%, and 7.2% in the conventional group, respectively. Although both groups showed significant reductions in HbA1C levels, the reductions were larger in the vegan group than in the conventional group (-0.5% vs. -0.2%; p-for-interaction = 0.017). When only considering participants with high compliance, the difference in HbA1c level reduction between the groups was found to be larger (-0.9% vs. -0.3%). The beneficial effect of vegan diets was noted even after adjusting for changes in total energy intake or waist circumference over the 12 weeks. Conclusion Both diets led to reductions in HbA1c levels; however, glycemic control was better with the vegan diet than with the conventional diet. Thus, the dietary guidelines for patients with T2D should include a vegan diet for the better management and treatment. However, further studies are needed to evaluate the long-term effects of a vegan diet, and to identify potential explanations of the underlying mechanisms. Trial Registration CRiS KCT0001771
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Affiliation(s)
- Yu-Mi Lee
- Department of Preventative Medicine, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Se-A Kim
- Department of Biomedical Science, Kyungpook National University, Daegu, Korea
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Korea
| | - In-Kyu Lee
- Department of Endocrinology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Jung-Guk Kim
- Department of Endocrinology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Keun-Gyu Park
- Department of Endocrinology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Ji-Yun Jeong
- Department of Endocrinology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Jae-Han Jeon
- Department of Endocrinology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Ji-Yeon Shin
- Department of Preventive Medicine, School of Medicine, Eulji University, Daejeon, Republic of Korea
| | - Duk-Hee Lee
- Department of Preventative Medicine, School of Medicine, Kyungpook National University, Daegu, Korea
- Department of Biomedical Science, Kyungpook National University, Daegu, Korea
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Korea
- * E-mail:
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Montalcini T, De Bonis D, Ferro Y, Carè I, Mazza E, Accattato F, Greco M, Foti D, Romeo S, Gulletta E, Pujia A. High Vegetable Fats Intake Is Associated with High Resting Energy Expenditure in Vegetarians. Nutrients 2015; 7:5933-47. [PMID: 26193314 PMCID: PMC4517036 DOI: 10.3390/nu7075259] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/08/2015] [Accepted: 07/10/2015] [Indexed: 12/20/2022] Open
Abstract
It has been demonstrated that a vegetarian diet may be effective in reducing body weight, however, the underlying mechanisms are not entirely clear. We investigated whether there is a difference in resting energy expenditure between 26 vegetarians and 26 non-vegetarians and the correlation between some nutritional factors and inflammatory markers with resting energy expenditure. In this cross-sectional study, vegetarians and non-vegetarians were matched by age, body mass index and gender. All underwent instrumental examinations to assess the difference in body composition, nutrient intake and resting energy expenditure. Biochemical analyses and 12 different cytokines and growth factors were measured as an index of inflammatory state. A higher resting energy expenditure was found in vegetarians than in non-vegetarians (p = 0.008). Furthermore, a higher energy from diet, fibre, vegetable fats intake and interleukin-β (IL-1β) was found between the groups. In the univariate and multivariable analysis, resting energy expenditure was associated with vegetarian diet, free-fat mass and vegetable fats (p < 0.001; Slope in statistic (B) = 4.8; β = 0.42). After adjustment for cytokines, log10 interleukin-10 (IL-10) still correlated with resting energy expenditure (p = 0.02). Resting energy expenditure was positively correlated with a specific component of the vegetarian's diet, i.e., vegetable fats. Furthermore, we showed that IL-10 was positively associated with resting energy expenditure in this population.
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Affiliation(s)
- Tiziana Montalcini
- Department of Clinical and Experimental Medicine, University Magna Grecia, Catanzaro 88100, Italy.
| | - Daniele De Bonis
- Department of Medical and Surgical Science, University Magna Grecia, Catanzaro 88100, Italy.
| | - Yvelise Ferro
- Department of Medical and Surgical Science, University Magna Grecia, Catanzaro 88100, Italy.
| | - Ilaria Carè
- Department of Medical and Surgical Science, University Magna Grecia, Catanzaro 88100, Italy.
| | - Elisa Mazza
- Department of Medical and Surgical Science, University Magna Grecia, Catanzaro 88100, Italy.
| | - Francesca Accattato
- Department of Health Sciences, University Magna Grecia, Catanzaro 88100, Italy.
| | - Marta Greco
- Department of Health Sciences, University Magna Grecia, Catanzaro 88100, Italy.
| | - Daniela Foti
- Department of Health Sciences, University Magna Grecia, Catanzaro 88100, Italy.
| | - Stefano Romeo
- Department of Medical and Surgical Science, University Magna Grecia, Catanzaro 88100, Italy.
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg SE-413 45, Sweden.
| | - Elio Gulletta
- Department of Health Sciences, University Magna Grecia, Catanzaro 88100, Italy.
| | - Arturo Pujia
- Department of Medical and Surgical Science, University Magna Grecia, Catanzaro 88100, Italy.
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Kim Y, Keogh J, Clifton P. A review of potential metabolic etiologies of the observed association between red meat consumption and development of type 2 diabetes mellitus. Metabolism 2015; 64:768-79. [PMID: 25838035 DOI: 10.1016/j.metabol.2015.03.008] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/02/2015] [Accepted: 03/15/2015] [Indexed: 01/12/2023]
Abstract
Epidemiological studies suggest that red and processed meat consumption is related to an increased risk of type 2 diabetes. However, it is not clearly understood which components of red and processed meat contribute to this increased risk. This review examines potential mechanisms addressing the role of saturated fatty acid, sodium, advanced glycation end products (AGEs), nitrates/nitrites, heme iron, trimethylamine N-oxide (TMAO), branched amino acids (BCAAs) and endocrine disruptor chemicals (EDCs) in the development of type 2 diabetes based on data from published clinical trials and animal models. TMAO which is derived from dietary carnitine and choline by the action of bacterial enzymes followed by oxidation in the liver may be a strong candidate molecule mediating the risk of type 2 diabetes. BCAAs may induce insulin resistance via the mammalian target of rapamycin complex 1 (mTORC1) and ribosomal protein S6 kinase β 1 (S6k1)-associated pathways. The increased risk associated with processed meat compared with red meat suggests that there are interactions between the saturated fat, salt, and nitrates in processed meat and iron, AGEs and TMAO. Intervention studies are required to clarify potential mechanisms and explore interactions among components, in order to make firm recommendations on red and processed meat consumption.
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Affiliation(s)
- Yoona Kim
- School of Pharmacy and Medical Science, University of South Australia, Australia
| | - Jennifer Keogh
- School of Pharmacy and Medical Science, University of South Australia, Australia
| | - Peter Clifton
- School of Pharmacy and Medical Science, University of South Australia, Australia.
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26
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Kahleova H, Pelikanova T. Vegetarian Diets in the Prevention and Treatment of Type 2 Diabetes. J Am Coll Nutr 2015; 34:448-58. [DOI: 10.1080/07315724.2014.976890] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Awareness and perception of plant-based diets for the treatment and management of type 2 diabetes in a community education clinic: a pilot study. J Nutr Metab 2015; 2015:236234. [PMID: 25802755 PMCID: PMC4329824 DOI: 10.1155/2015/236234] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/08/2015] [Indexed: 11/18/2022] Open
Abstract
Objective. To assess awareness, barriers, and promoters of plant-based diet use for management of type 2 diabetes (T2D) for the development of an appropriate educational program. Design. Cross-sectional study of patients and healthcare providers. Setting. Regional Diabetes Education Centre in ON, Canada. Participants. n = 98 patients attending the Diabetes Education Centre and n = 25 healthcare providers. Variables Measures. Patient questionnaires addressed demographics, health history, and eating patterns, as well as current knowledge, confidence levels, barriers to, promoters of, and interests in plant-based diets. Staff questionnaires addressed attitudes and current practice with respect to plant-based diets. Analysis. Mean values, frequency counts, and logistic regression (alpha = 0.05). Results. Few respondents (9%) currently followed a plant-based diet, but 66% indicated willingness to follow one for 3 weeks. Family eating preferences and meal planning skills were common barriers to diet change. 72% of healthcare providers reported knowledge of plant-based diets for diabetes management but low levels of practice. Conclusions and Implications. Patient awareness of the benefits of a plant-based diet for the management of diabetes remains suboptimal and may be influenced by perception of diabetes educators and clinicians. Given the reported willingness to try (but low current use of) plant-based diets, educational interventions targeting patient and provider level knowledge are warranted.
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Yokoyama Y, Barnard ND, Levin SM, Watanabe M. Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Cardiovasc Diagn Ther 2014; 4:373-82. [PMID: 25414824 DOI: 10.3978/j.issn.2223-3652.2014.10.04] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 10/08/2014] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Previous studies have suggested an association between vegetarian diets and improvements in glycemic control in diabetes, although this relationship is not well established. No meta-analysis of these studies has been performed. METHODS To conduct a systematic review and meta-analysis of controlled clinical trials examining the association between vegetarian diets and glycemic control in type 2 diabetes. DATA SOURCE The electronic databases Medline, Web of Science, Excerpta Medica Database (EMBASE), and Cochrane Central Register of Controlled Trials were searched for articles published in any language through December 9, 2013. STUDY SELECTION The following criteria were used for study inclusion: (I) age of participants >20 years; (II) vegetarian diet as intervention; (III) mean difference in hemoglobin A1c (HbA1c) and/or fasting blood glucose levels used as outcomes; and (IV) controlled trials, duration ≥4 weeks. Exclusion criteria were: (I) not an original investigation; (II) duplicate samples; (III) diabetes other than type 2; (IV) multiple interventions; and (V) uncontrolled studies. DATA EXTRACTION AND SYNTHESIS The data collected included study design, baseline population characteristics, dietary data, and outcomes. Data were pooled using a random-effects model. MAIN OUTCOMES AND MEASURES Differences in HbA1c and fasting blood glucose levels associated with vegetarian diets were assessed. RESULTS Of 477 studies identified, six met the inclusion criteria (n=255, mean age 42.5 years). Consumption of vegetarian diets was associated with a significant reduction in HbA1c [-0.39 percentage point; 95% confidence interval (CI), -0.62 to -0.15; P=0.001; I(2)=3.0; P for heterogeneity =0.389], and a non-significant reduction in fasting blood glucose concentration (-0.36 mmol/L; 95% CI, -1.04 to 0.32; P=0.301; I(2)=0; P for heterogeneity =0.710), compared with consumption of comparator diets. CONCLUSIONS Consumption of vegetarian diets is associated with improved glycemic control in type 2 diabetes. PROSPERO registration number is CRD42013004370.
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Affiliation(s)
- Yoko Yokoyama
- 1 Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan ; 2 Department of Medicine, The George Washington University School of Medicine, Washington, DC, USA ; 3 Physicians Committee for Responsible Medicine, Washington, DC, USA ; 4 Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan ; 5 Health Science Laboratory, Graduate School of Media and Governance, Faculty of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan
| | - Neal D Barnard
- 1 Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan ; 2 Department of Medicine, The George Washington University School of Medicine, Washington, DC, USA ; 3 Physicians Committee for Responsible Medicine, Washington, DC, USA ; 4 Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan ; 5 Health Science Laboratory, Graduate School of Media and Governance, Faculty of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan
| | - Susan M Levin
- 1 Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan ; 2 Department of Medicine, The George Washington University School of Medicine, Washington, DC, USA ; 3 Physicians Committee for Responsible Medicine, Washington, DC, USA ; 4 Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan ; 5 Health Science Laboratory, Graduate School of Media and Governance, Faculty of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan
| | - Mitsuhiro Watanabe
- 1 Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan ; 2 Department of Medicine, The George Washington University School of Medicine, Washington, DC, USA ; 3 Physicians Committee for Responsible Medicine, Washington, DC, USA ; 4 Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan ; 5 Health Science Laboratory, Graduate School of Media and Governance, Faculty of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa, 252-0882, Japan
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Glick-Bauer M, Yeh MC. The health advantage of a vegan diet: exploring the gut microbiota connection. Nutrients 2014; 6:4822-38. [PMID: 25365383 PMCID: PMC4245565 DOI: 10.3390/nu6114822] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/16/2014] [Accepted: 10/27/2014] [Indexed: 02/07/2023] Open
Abstract
This review examines whether there is evidence that a strict vegan diet confers health advantages beyond that of a vegetarian diet or overall healthy eating. Few studies include vegan subjects as a distinct experimental group, yet when vegan diets are directly compared to vegetarian and omnivorous diets, a pattern of protective health benefits emerges. The relatively recent inclusion of vegan diets in studies of gut microbiota and health allows us the opportunity to assess whether the vegan gut microbiota is distinct, and whether the health advantages characteristic of a vegan diet may be partially explained by the associated microbiota profile. The relationship between diet and the intestinal microbial profile appears to follow a continuum, with vegans displaying a gut microbiota most distinct from that of omnivores, but not always significantly different from that of vegetarians. The vegan gut profile appears to be unique in several characteristics, including a reduced abundance of pathobionts and a greater abundance of protective species. Reduced levels of inflammation may be the key feature linking the vegan gut microbiota with protective health effects. However, it is still unclear whether a therapeutic vegan diet can be prescribed to alter the gut microflora for long-term health benefits.
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Affiliation(s)
- Marian Glick-Bauer
- Nutrition Program, CUNY School of Public Health, Hunter College, City University of New York, 2180 Third Avenue, Room 614, New York, NY 10035, USA.
| | - Ming-Chin Yeh
- Nutrition Program, CUNY School of Public Health, Hunter College, City University of New York, 2180 Third Avenue, Room 614, New York, NY 10035, USA.
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Trepanowski JF, Varady KA. Veganism Is a Viable Alternative to Conventional Diet Therapy for Improving Blood Lipids and Glycemic Control. Crit Rev Food Sci Nutr 2014; 55:2004-13. [DOI: 10.1080/10408398.2012.736093] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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31
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Meat consumption as a risk factor for type 2 diabetes. Nutrients 2014; 6:897-910. [PMID: 24566443 PMCID: PMC3942738 DOI: 10.3390/nu6020897] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/04/2014] [Accepted: 02/11/2014] [Indexed: 11/17/2022] Open
Abstract
Disease risk factors identified in epidemiological studies serve as important public health tools, helping clinicians identify individuals who may benefit from more aggressive screening or risk-modification procedures, allowing policymakers to prioritize intervention programs, and encouraging at-risk individuals to modify behavior and improve their health. These factors have been based primarily on evidence from cross-sectional and prospective studies, as most do not lend themselves to randomized trials. While some risk factors are not modifiable, eating habits are subject to change through both individual action and broader policy initiatives. Meat consumption has been frequently investigated as a variable associated with diabetes risk, but it has not yet been described as a diabetes risk factor. In this article, we evaluate the evidence supporting the use of meat consumption as a clinically useful risk factor for type 2 diabetes, based on studies evaluating the risks associated with meat consumption as a categorical dietary characteristic (i.e., meat consumption versus no meat consumption), as a scalar variable (i.e., gradations of meat consumption), or as part of a broader dietary pattern.
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32
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Gojda J, Patková J, Jaček M, Potočková J, Trnka J, Kraml P, Anděl M. Higher insulin sensitivity in vegans is not associated with higher mitochondrial density. Eur J Clin Nutr 2013; 67:1310-5. [PMID: 24149445 DOI: 10.1038/ejcn.2013.202] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 09/03/2013] [Accepted: 09/12/2013] [Indexed: 02/04/2023]
Abstract
BACKGROUND/OBJECTIVES Vegans have a lower incidence of insulin resistance (IR)-associated diseases and a higher insulin sensitivity (IS) compared with omnivores. The aim of this study was to examine whether the higher IS in vegans relates to markers of mitochondrial biogenesis and to intramyocellular lipid (IMCL) content. SUBJECTS/METHODS Eleven vegans and 10 matched (race, age, sex, body mass index, physical activity and energy intake) omnivorous controls were enrolled in a case-control study. Anthropometry, bioimpedance (BIA), ultrasound measurement of visceral and subcutaneous fat layer, parameters of glucose and lipid homeostasis, hyperinsulinemic euglycemic clamp and muscle biopsies were performed. Citrate synthase (CS) activity, mitochondrial DNA (mtDNA) and IMCL content were assessed in skeletal muscle samples. RESULTS Both groups were comparable in anthropometric and BIA parameters, physical activity and protein-energy intake. Vegans had significantly higher glucose disposal (M-value, vegans 8.11±1.51 vs controls 6.31±1.57 mg/kg/min, 95% confidence interval: 0.402 to 3.212, P=0.014), slightly lower IMCL content (vegans 13.91 (7.8 to 44.0) vs controls 17.36 (12.4 to 78.5) mg/g of muscle, 95% confidence interval: -7.594 to 24.550, P=0.193) and slightly higher relative muscle mtDNA amount (vegans 1.36±0.31 vs controls 1.13±0.36, 95% confidence interval:-0.078 to 0.537, P=0.135). No significant differences were found in CS activity (vegans 18.43±5.05 vs controls 18.16±5.41 μmol/g/min, 95% confidence interval: -4.503 to 5.050, P=0.906). CONCLUSIONS Vegans have a higher IS, but comparable mitochondrial density and IMCL content with omnivores. This suggests that a decrease in whole-body glucose disposal may precede muscle lipid accumulation and mitochondrial dysfunction in IR development.
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Affiliation(s)
- J Gojda
- 1] Centre for Research on Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic [2] Second Department of Internal Medicine, Faculty Hospital Kralovske Vinohrady, Prague, Czech Republic
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Chiang JK, Lin YL, Chen CL, Ouyang CM, Wu YT, Chi YC, Huang KC, Yang WS. Reduced risk for metabolic syndrome and insulin resistance associated with ovo-lacto-vegetarian behavior in female Buddhists: a case-control study. PLoS One 2013; 8:e71799. [PMID: 23951247 PMCID: PMC3739750 DOI: 10.1371/journal.pone.0071799] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 06/28/2013] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION The association of vegetarian status with the risk of metabolic syndrome (MetS) is not clear. In Asia, Buddhists often have vegetarian behavior for religious rather than for health reasons. We hypothesize that the vegetarian in Buddhism is associated with better metabolic profiles, lower risk for the MetS and insulin resistance (IR). METHODS We enrolled 391 female vegetarians (~80% lacto-ovo-vegetarians) and 315 non-vegetarians from health-checkup clinics at a Buddhist hospital in Taiwan. RESULTS The vegetarian status was associated with lower body mass index, smaller waist circumference, lower total cholesterol, lower low density lipoprotein-cholesterol (LDL-C), and lower HDL-C in multivariate linear regression analyses. Despite having lower HDL-C level, the vegetarians had significantly lower total cholesterol/HDL-C and LDL-C/HDL-C ratios. After adjusting the other covariates, the risks for the MetS were lower for ovo-lacto-vegetarians of 1-11 years and >11 years respectively by 54% (odds ratio [OR] =0.46, 95%C.I.:0.26-0.79) and 57% (OR=0.43, 95%C.I.:0.23-0.76) compared to non-vegetarians by the IDF criteria. Likewise, they were lower respectively by 45% (OR=0.55, 95%C.I.:0.32-0.92) and 42% (OR=0.58, 95%C.I.:0.33-0.997), for the MetS by the modified NCEP criteria. In the subgroup of non-diabetic subjects, the vegetarians also had lower risk for IR by HOMA compared to the non-vegetarians (OR=0.71, 95%C.I.:0.48-1.06). CONCLUSION The vegetarian behavior, mainly lacto-ovo-vegetarian, related to Buddhism, although not meant for its health effects, is associated with reduced risk for the MetS and IR and may potentially provide metabolic and cardiovascular protective effects in women.
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Affiliation(s)
- Jui-Kun Chiang
- Department of Family Medicine, Dalin Tzuchi Hospital, Buddhist Tzuchi Medical Foundation, Chiayi, Taiwan
| | - Ying-Lung Lin
- Department of Family Medicine, Dalin Tzuchi Hospital, Buddhist Tzuchi Medical Foundation, Chiayi, Taiwan
| | - Chi-Ling Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Epidemiology, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Chung-Mei Ouyang
- Department of Dietetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ying-Tai Wu
- Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Chiao Chi
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kuo-Chin Huang
- Department of Family Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Wei-Shiung Yang
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail:
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Vegetarian diet-induced increase in linoleic acid in serum phospholipids is associated with improved insulin sensitivity in subjects with type 2 diabetes. Nutr Diabetes 2013; 3:e75. [PMID: 23775014 PMCID: PMC3697401 DOI: 10.1038/nutd.2013.12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND AIMS: Fatty acids are important cellular constituents that may affect many metabolic processes relevant for the development of diabetes and its complications. We showed previously that vegetarian diet leads to greater increase in metabolic clearance rate of glucose (MCR) than conventional hypocaloric diet. The aim of this secondary analysis was to explore the role of changes in fatty acid composition of serum phospholipids in diet- and exercise-induced changes in MCR in subjects with type 2 diabetes (T2D). METHODS: Subjects with T2D (n=74) were randomly assigned into a vegetarian group (VG, n=37) following vegetarian diet or a control group (CG, n=37) following a conventional diet. Both diets were calorie restricted (−500 kcal day–1). Participants were examined at baseline, 12 weeks of diet intervention and 24 weeks (subsequent 12 weeks of diet were combined with aerobic exercise). The fatty acid composition of serum phospholipids was measured by gas liquid chromatography. MCR was measured by hyperinsulinemic isoglycemic clamp. Visceral fat (VF) was measured by magnetic resonance imaging. RESULTS: Linoleic acid (LA; 18:2n6) increased in VG (P=0.04), whereas it decreased in CG (P=0.04) in response to dietary interventions. It did not change significantly after the addition of exercise in either group (group × time P<0.001). In VG, changes in 18:2n6 correlated positively with changes in MCR (r=+0.22; P=0.04) and negatively with changes in VF (r=−0.43; P=0.01). After adjustment for changes in body mass index, the association between 18:2n6 and MCR was no longer significant. The addition of exercise resulted in greater changes of phospholipid fatty acids composition in VG than in CG. CONCLUSION: We demonstrated that the insulin-sensitizing effect of a vegetarian diet might be related to the increased proportion of LA in serum phospholipids.
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Kim MH, Bae YJ. Postmenopausal vegetarians' low serum ferritin level may reduce the risk for metabolic syndrome. Biol Trace Elem Res 2012; 149:34-41. [PMID: 22528775 DOI: 10.1007/s12011-012-9405-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 03/26/2012] [Indexed: 11/24/2022]
Abstract
The present study was conducted to compare the serum ferritin status between the postmenopausal vegetarians and non-vegetarians and to identify the relation of serum ferritin with metabolic syndrome (MetS) risk factors in postmenopausal women. The two study groups consisted of postmenopausal vegetarians (n=59) who maintained a vegetarian diet for over 20 years and age-matched non-vegetarian controls (n=48). Anthropometric measurements, dietary intakes, serum metabolic syndrome-related parameters, and serum ferritin level between the two groups were compared. The vegetarians exhibited significantly lower weight (p<0.01), body mass index (BMI) (p<0.001), percentage of body fat (p<0.001), waist circumference (p<0.01), SBP (p<0.001), DBP (p<0.001), and fasting glucose (p<0.05). According to the National Cholesterol Education Program (NCEP)-Adult Treatment Panel III criteria for MetS applying Korean guidelines for waist circumference, the prevalence of MetS was lower in vegetarians (33.9 %) than in non-vegetarians (47.9 %). Vegetarians had significantly lower serum level of ferritin (p<0.01) than non-vegetarians. In the correlation analysis, serum ferritin was positively related to fasting glucose (r=0.264, p<0.01), triglycerides (r=0.232, p<0.05), and the NCEP score (r=0.214, p<0.05) and negatively related to high-density lipoprotein-cholesterol (r=-0.225, p<0.05) after adjusting for BMI, lifestyle, and dietary factors (animal protein, animal fat, and dietary fiber intake). In conclusion, postmenopausal vegetarians had lower MetS presence and a lower serum ferritin level compared to non-vegetarians. Furthermore, vegetarians' low serum ferritin level may reduce the risk of MetS in postmenopausal women.
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Affiliation(s)
- Mi-Hyun Kim
- Department of Food and Nutrition, Kangwon National University, Samcheok 245-711, South Korea.
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Yang SY, Li XJ, Zhang W, Liu CQ, Zhang HJ, Lin JR, Yan B, Yu YX, Shi XL, Li CD, Li WH. Chinese lacto-vegetarian diet exerts favorable effects on metabolic parameters, intima-media thickness, and cardiovascular risks in healthy men. Nutr Clin Pract 2012; 27:392-8. [PMID: 22412169 DOI: 10.1177/0884533611436173] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND To investigate whether the Chinese lacto-vegetarian diet has protective effects on metabolic and cardiovascular disease (CVD). METHODS One hundred sixty-nine healthy Chinese lacto-vegetarians and 126 healthy omnivore men aged 21-76 years were enrolled. Anthropometric indexes, lipid profile, insulin sensitivity, pancreatic β cell function, and intima-media thickness (IMT) of carotid arteries were assessed and compared. Cardiovascular risk points and probability of developing CVD in 5-10 years in participants aged 24-55 years were calculated. RESULTS Compared with omnivores, lacto-vegetarians had remarkably lower body mass index, systolic and diastolic blood pressure, and serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, γ-glutamyl transferase, serum creatinine, uric acid, fasting blood glucose, as well as lower total cholesterol/high-density lipoprotein cholesterol ratio. Vegetarians also had higher homeostasis model assessment β cell function and insulin secretion index and thinner carotid IMT than the omnivores did. These results corresponded with lower cardiovascular risk points and probability of developing CVD in 5-10 years in vegetarians 24-55 years old. CONCLUSIONS In healthy Chinese men, the lacto-vegetarian diet seems to exert protective effects on blood pressure, lipid profiles, and metabolic parameters and results in significantly lower carotid IMT. Lower CVD risks found in vegetarians also reflect the beneficial effect of the Chinese lacto-vegetarian diet.
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Affiliation(s)
- Shu-Yu Yang
- Department of Diabetes, the First Affiliated Hospital of Xiamen University, Xiamen, PR China
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Kahleova H, Matoulek M, Malinska H, Oliyarnik O, Kazdova L, Neskudla T, Skoch A, Hajek M, Hill M, Kahle M, Pelikanova T. Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes. Diabet Med 2011; 28:549-59. [PMID: 21480966 PMCID: PMC3427880 DOI: 10.1111/j.1464-5491.2010.03209.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AIMS The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes. METHODS A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat. RESULTS Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P < 0.001). Body weight decreased more in the experimental group than in the control group [-6.2 kg (95% CI -6.6 to -5.3) vs. -3.2 kg (95% CI -3.7 to -2.5); interaction group × time P = 0.001]. An increase in insulin sensitivity was significantly greater in the experimental group than in the control group [30% (95% CI 24.5-39) vs. 20% (95% CI 14-25), P = 0.04]. A reduction in both visceral and subcutaneous fat was greater in the experimental group than in the control group (P = 0.007 and P = 0.02, respectively). Plasma adiponectin increased (P = 0.02) and leptin decreased (P = 0.02) in the experimental group, with no change in the control group. Vitamin C, superoxide dismutase and reduced glutathione increased in the experimental group (P = 0.002, P < 0.001 and P = 0.02, respectively). Differences between groups were greater after the addition of exercise training. Changes in insulin sensitivity and enzymatic oxidative stress markers correlated with changes in visceral fat. CONCLUSIONS A calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet.
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Affiliation(s)
- H Kahleova
- Institute for Clinical and Experimental Medicine Charles University, 1st Faculty of Medicine Institute of Endocrinology, Prague, Czech Republic
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Comparison of sex hormonal and metabolic profiles between omnivores and vegetarians in pre- and post-menopausal women. Br J Nutr 2010; 104:222-6. [PMID: 20211044 DOI: 10.1017/s0007114510000619] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of the present study was to investigate the sex hormonal and metabolic profiles in vegetarians and compare these with the profiles in omnivores. The design of the present study was cross-sectional. The study sample of pre- and post-menopausal women included forty-one omnivores and twenty-one vegetarians. Thereafter we determined: (1) plasma sex hormones, (2) fasting insulin, NEFA as well as apo-A and apo-B, (3) BMI, (4) a dietary profile (3 d dietary records), (5) physical activity and (6) total faecal excretion per 72 h and total urinary excretion per 72 h. Vegetarians showed higher levels of sex hormone-binding globulin (SHBG), apo-A, total faecal excretion per 72 h and total fibre intake as well as lower levels of apo-B, free oestradiol, free testosterone, dehydroepiandrosterone sulfate (DHEA-s) and BMI. Interestingly, after controlling for BMI, significant differences between groups still persisted except for apo-B. Moreover, stepwise regression analysis showed that total fibre intake explained 15.2 % of the variation in SHBG in our cohort, which accounted for the greatest source of unique variance. Results of the present study indicate that pre- and post-menopausal vegetarians present higher concentrations of SHBG, which could be explained, in part, by higher levels of fibre intake. This may explain, at least in part, the lower risk of developing type 2 diabetes.
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Brechtel K, Machann J, Pick M, Schaefer JF, Claussen CD, Schick F. Changes in muscular lipids in unilateral isolated hypertrophy of gastrocnemius muscle can be revealed by 1H MR spectroscopy. Korean J Radiol 2009; 10:581-6. [PMID: 19885314 PMCID: PMC2770818 DOI: 10.3348/kjr.2009.10.6.581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/29/2009] [Indexed: 11/15/2022] Open
Abstract
Objective To test whether proton magnetic resonance spectroscopy (1H-MRS) reveals changes in the lipid content of the gastrocnemius muscle (GM) and soleus muscle (SOL) of a patient with unilateral isolated hypertrophy of the right GM. Materials and Methods 1H-MRS was performed on a 1.5 Tesla (T) whole-body unit. Muscular lipids inside SOL and GM were assessed in both calves of the patient by a STEAM (stimulated echo acquisition mode) localization sequence. Results were compared to a control group of four healthy volunteers. Results Total amount of muscular lipids in the hypertrophic GM of the patient was clearly increased compared to the controls (38.7 versus 21.8±3.5 a.u.) while intramyocellular lipids of the adjacent SOL were lower compared to the contralateral healthy leg. Conclusion Muscular lipids are substrates for metabolism and can be assessed non-invasively by 1H-MRS. 1H-MRS is considered to be a helpful tool in clinical assessment of muscle metabolism in cases with muscular hypo- or hypertrophy.
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Affiliation(s)
- Klaus Brechtel
- Section on Experimental Radiology, Department of Diagnostic Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen, Germany
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Barnard ND, Katcher HI, Jenkins DJA, Cohen J, Turner-McGrievy G. Vegetarian and vegan diets in type 2 diabetes management. Nutr Rev 2009; 67:255-63. [PMID: 19386029 DOI: 10.1111/j.1753-4887.2009.00198.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Vegetarian and vegan diets offer significant benefits for diabetes management. In observational studies, individuals following vegetarian diets are about half as likely to develop diabetes, compared with non-vegetarians. In clinical trials in individuals with type 2 diabetes, low-fat vegan diets improve glycemic control to a greater extent than conventional diabetes diets. Although this effect is primarily attributable to greater weight loss, evidence also suggests that reduced intake of saturated fats and high-glycemic-index foods, increased intake of dietary fiber and vegetable protein, reduced intramyocellular lipid concentrations, and decreased iron stores mediate the influence of plant-based diets on glycemia. Vegetarian and vegan diets also improve plasma lipid concentrations and have been shown to reverse atherosclerosis progression. In clinical studies, the reported acceptability of vegetarian and vegan diets is comparable to other therapeutic regimens. The presently available literature indicates that vegetarian and vegan diets present potential advantages for the management of type 2 diabetes.
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Affiliation(s)
- Neal D Barnard
- Department of Medicine, George Washington University School of Medicine, Washington, DC, USA.
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Barnard ND, Cohen J, Jenkins DJA, Turner-McGrievy G, Gloede L, Green A, Ferdowsian H. A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial. Am J Clin Nutr 2009; 89:1588S-1596S. [PMID: 19339401 PMCID: PMC2677007 DOI: 10.3945/ajcn.2009.26736h] [Citation(s) in RCA: 261] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Low-fat vegetarian and vegan diets are associated with weight loss, increased insulin sensitivity, and improved cardiovascular health. OBJECTIVE We compared the effects of a low-fat vegan diet and conventional diabetes diet recommendations on glycemia, weight, and plasma lipids. DESIGN Free-living individuals with type 2 diabetes were randomly assigned to a low-fat vegan diet (n = 49) or a diet following 2003 American Diabetes Association guidelines (conventional, n = 50) for 74 wk. Glycated hemoglobin (Hb A(1c)) and plasma lipids were assessed at weeks 0, 11, 22, 35, 48, 61, and 74. Weight was measured at weeks 0, 22, and 74. RESULTS Weight loss was significant within each diet group but not significantly different between groups (-4.4 kg in the vegan group and -3.0 kg in the conventional diet group, P = 0.25) and related significantly to Hb A(1c) changes (r = 0.50, P = 0.001). Hb A(1c) changes from baseline to 74 wk or last available values were -0.34 and -0.14 for vegan and conventional diets, respectively (P = 0.43). Hb A(1c) changes from baseline to last available value or last value before any medication adjustment were -0.40 and 0.01 for vegan and conventional diets, respectively (P = 0.03). In analyses before alterations in lipid-lowering medications, total cholesterol decreased by 20.4 and 6.8 mg/dL in the vegan and conventional diet groups, respectively (P = 0.01); LDL cholesterol decreased by 13.5 and 3.4 mg/dL in the vegan and conventional groups, respectively (P = 0.03). CONCLUSIONS Both diets were associated with sustained reductions in weight and plasma lipid concentrations. In an analysis controlling for medication changes, a low-fat vegan diet appeared to improve glycemia and plasma lipids more than did conventional diabetes diet recommendations. Whether the observed differences provide clinical benefit for the macro- or microvascular complications of diabetes remains to be established. This trial was registered at clinicaltrials.gov as NCT00276939.
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Affiliation(s)
- Neal D Barnard
- Department of Medicine, George Washington University School of Medicine, Washington, DC, USA.
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Elkan AC, Sjöberg B, Kolsrud B, Ringertz B, Hafström I, Frostegård J. Gluten-free vegan diet induces decreased LDL and oxidized LDL levels and raised atheroprotective natural antibodies against phosphorylcholine in patients with rheumatoid arthritis: a randomized study. Arthritis Res Ther 2008; 10:R34. [PMID: 18348715 PMCID: PMC2453753 DOI: 10.1186/ar2388] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 02/01/2008] [Accepted: 03/18/2008] [Indexed: 02/02/2023] Open
Abstract
Introduction The purpose of this study was to investigate the effects of vegan diet in patients with rheumatoid arthritis (RA) on blood lipids oxidized low-density lipoprotein (oxLDL) and natural atheroprotective antibodies against phosphorylcholine (anti-PCs). Methods Sixty-six patients with active RA were randomly assigned to either a vegan diet free of gluten (38 patients) or a well-balanced non-vegan diet (28 patients) for 1 year. Thirty patients in the vegan group completed more than 3 months on the diet regimen. Blood lipids were analyzed by routine methods, and oxLDL and anti-PCs were analyzed by enzyme-linked immunosorbent assay. Data and serum samples were obtained at baseline and after 3 and 12 months. Results Mean ages were 50.0 years for the vegan group and 50.8 years for controls. Gluten-free vegan diet induced lower body mass index (BMI) and low-density lipoprotein (LDL) and higher anti-PC IgM than control diet (p < 0.005). In the vegan group, BMI, LDL, and cholesterol decreased after both 3 and 12 months (p < 0.01) and oxLDL after 3 months (p = 0.021) and trendwise after 12 months (p = 0.090). Triglycerides and high-density lipoprotein did not change. IgA anti-PC levels increased after 3 months (p = 0.027) and IgM anti-PC levels increased trendwise after 12 months (p = 0.057). There was no difference in IgG anti-PC levels. In the control diet group, IgM anti-PC levels decreased both after 3 and 12 months (p < 0.01). When separating vegan patients into clinical responders and non-responders at 12 months, the effects on oxLDL and anti-PC IgA were seen only in responders (p < 0.05). Conclusion A gluten-free vegan diet in RA induces changes that are potentially atheroprotective and anti-inflammatory, including decreased LDL and oxLDL levels and raised anti-PC IgM and IgA levels.
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Affiliation(s)
- Ann-Charlotte Elkan
- Rheumatology Unit, Karolinska Institutet at Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden.
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Denise Robertson M. Metabolic cross talk between the colon and the periphery: implications for insulin sensitivity. Proc Nutr Soc 2007; 66:351-61. [PMID: 17637087 DOI: 10.1017/s0029665107005617] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Until recently, a glance at a standard undergraduate textbook would have given the impression that the colon was merely a storage organ for faeces and maybe something about the absorption of electrolytes and water. In reality, the colon is a highly-metabolically-active organ, the function of which has implications not only for the remainder of the digestive tract, but also for peripheral organs such as adipose tissue (AT), liver and skeletal muscle. The present review focuses on two distinct but complementary areas: (1) the metabolic adaptation that occurs following surgical removal of colonic tissue; (2) the effect of modulating the colon in situ in terms of postprandial metabolism, insulin sensitivity and disease risk. Work in these two areas points to the colon being important in modulating normal tissue insulin sensitivity. The role of fatty acids is central to the insulin sensitivity hypothesis. AT acts as a daily 'buffer' for fatty acids. However, following colonic resection there is an apparent change in AT function. There is an increase in the AT lipolysis rate, resulting in the release of excess fatty acids into the circulation and consequently the take up of excess fatty acids into skeletal muscle. This resultant increase in either storage of lipid or its oxidation would result in a reduction in insulin sensitivity. The insulin-sensitising effects of high-fibre diets are also related to changes in AT function and fatty acid metabolism, but manipulating colonic tissue in situ allows the mechanisms to be elucidated. This research area is an exciting one, involving the potential role of SCFA (the absorbed by-products of colonic bacterial fermentation) acting directly on peripheral tissues, following the recent identification of G-protein-coupled receptors specific for these ligands.
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Affiliation(s)
- M Denise Robertson
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK.
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Barnard ND, Cohen J, Jenkins DJA, Turner-McGrievy G, Gloede L, Jaster B, Seidl K, Green AA, Talpers S. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care 2006; 29:1777-83. [PMID: 16873779 DOI: 10.2337/dc06-0606] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE We sought to investigate whether a low-fat vegan diet improves glycemic control and cardiovascular risk factors in individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS Individuals with type 2 diabetes (n = 99) were randomly assigned to a low-fat vegan diet (n = 49) or a diet following the American Diabetes Association (ADA) guidelines (n = 50). Participants were evaluated at baseline and 22 weeks. RESULTS Forty-three percent (21 of 49) of the vegan group and 26% (13 of 50) of the ADA group participants reduced diabetes medications. Including all participants, HbA(1c) (A1C) decreased 0.96 percentage points in the vegan group and 0.56 points in the ADA group (P = 0.089). Excluding those who changed medications, A1C fell 1.23 points in the vegan group compared with 0.38 points in the ADA group (P = 0.01). Body weight decreased 6.5 kg in the vegan group and 3.1 kg in the ADA group (P < 0.001). Body weight change correlated with A1C change (r = 0.51, n = 57, P < 0.0001). Among those who did not change lipid-lowering medications, LDL cholesterol fell 21.2% in the vegan group and 10.7% in the ADA group (P = 0.02). After adjustment for baseline values, urinary albumin reductions were greater in the vegan group (15.9 mg/24 h) than in the ADA group (10.9 mg/24 h) (P = 0.013). CONCLUSIONS Both a low-fat vegan diet and a diet based on ADA guidelines improved glycemic and lipid control in type 2 diabetic patients. These improvements were greater with a low-fat vegan diet.
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Affiliation(s)
- Neal D Barnard
- Department of Medicine, George Washington University School of Medicine, Washington, DC, USA.
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