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Wang H, Chen Y, Lin Y, Abesig J, Wu IX, Tam W. The methodological quality of individual participant data meta-analysis on intervention effects: systematic review. BMJ 2021; 373:n736. [PMID: 33875446 PMCID: PMC8054226 DOI: 10.1136/bmj.n736] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/09/2021] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To assess the methodological quality of individual participant data (IPD) meta-analysis and to identify areas for improvement. DESIGN Systematic review. DATA SOURCES Medline, Embase, and Cochrane Database of Systematic Reviews. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Systematic reviews with IPD meta-analyses of randomised controlled trials on intervention effects published in English. RESULTS 323 IPD meta-analyses covering 21 clinical areas and published between 1991 and 2019 were included: 270 (84%) were non-Cochrane reviews and 269 (84%) were published in journals with a high impact factor (top quarter). The IPD meta-analyses showed low compliance in using a satisfactory technique to assess the risk of bias of the included randomised controlled trials (43%, 95% confidence interval 38% to 48%), accounting for risk of bias when interpreting results (40%, 34% to 45%), providing a list of excluded studies with justifications (32%, 27% to 37%), establishing an a priori protocol (31%, 26% to 36%), prespecifying methods for assessing both the overall effects (44%, 39% to 50%) and the participant-intervention interactions (31%, 26% to 36%), assessing and considering the potential of publication bias (31%, 26% to 36%), and conducting a comprehensive literature search (19%, 15% to 23%). Up to 126 (39%) IPD meta-analyses failed to obtain IPD from 90% or more of eligible participants or trials, among which only 60 (48%) provided reasons and 21 (17%) undertook certain strategies to account for the unavailable IPD. CONCLUSIONS The methodological quality of IPD meta-analyses is unsatisfactory. Future IPD meta-analyses need to establish an a priori protocol with prespecified data syntheses plan, comprehensively search the literature, critically appraise included randomised controlled trials with appropriate technique, account for risk of bias during data analyses and interpretation, and account for unavailable IPD.
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Affiliation(s)
- Huan Wang
- Xiangya School of Public Health, Central South University, 5/F, Xiangya School of Public Health, No. 238, Shang ma Yuan ling Alley, Kaifu district, Changsha, Hunan, China
| | - Yancong Chen
- Xiangya School of Public Health, Central South University, 5/F, Xiangya School of Public Health, No. 238, Shang ma Yuan ling Alley, Kaifu district, Changsha, Hunan, China
| | - Yali Lin
- Xiangya School of Public Health, Central South University, 5/F, Xiangya School of Public Health, No. 238, Shang ma Yuan ling Alley, Kaifu district, Changsha, Hunan, China
| | - Julius Abesig
- Xiangya School of Public Health, Central South University, 5/F, Xiangya School of Public Health, No. 238, Shang ma Yuan ling Alley, Kaifu district, Changsha, Hunan, China
| | - Irene Xy Wu
- Xiangya School of Public Health, Central South University, 5/F, Xiangya School of Public Health, No. 238, Shang ma Yuan ling Alley, Kaifu district, Changsha, Hunan, China
| | - Wilson Tam
- Alice Lee Centre for Nursing Studies, National University of Singapore, Singapore
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Abstract
The role of carbohydrate in a healthy diet has been controversial. The confusion over carbohydrate has come from the long standing limitation of dietary recall studies as well as inability in many of these studies to delineate between the different types of carbohydrates. It is the aim of this paper, to understand and review the data on the role of carbohydrate as pertaining to weight, insulin resistance, diabetes, inflammation, lipids, as well as epidemiological data on long-term cardiovascular outcome and all-cause mortality. We have reviewed the latest epidemiological and intervention studies on fiber, whole grain, and refined carbohydrates on weight, diabetes, lipids as well as major adverse cardiac events that we deemed were scientifically rigorous. High intakes of dietary fiber and whole grains are associated with positive effects on metabolic health while diet high in sugar and refined carbohydrates have negative effects on cardiometabolic health. Consistent evidence indicates that low fat and low carbohydrate diets at comparable energy levels have similar effects on body weight. Large epidemiological studies show when carbohydrates are substituted for animal-derived fat or protein mortality increased while carbohydrate exchanged with plant based protein was associated with mortality reduction. Types of carbohydrate appear to be critical for mortality and cardiovascular events. Evidence shows that quality of the carbohydrate determine cardiometabolic health and cardiovascular events. Given that most people worldwide currently consume less than 20 g of dietary fiber per day with persistently high consumption of refined carbohydrates, current evidence emphasize the need for additional measures to increase the amount and the diversity of fiber intake for improvement of cardiometabolic and cardiovascular outcomes.
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Chao AM, Quigley KM, Wadden TA. Dietary interventions for obesity: clinical and mechanistic findings. J Clin Invest 2021; 131:140065. [PMID: 33393504 PMCID: PMC7773341 DOI: 10.1172/jci140065] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dietary modification is central to obesity treatment. Weight loss diets are available that include various permutations of energy restriction, macronutrients, foods, and dietary intake patterns. Caloric restriction is the common pathway for weight reduction, but different diets may induce weight loss by varied additional mechanisms, including by facilitating dietary adherence. This narrative Review of meta-analyses and select clinical trials found that lower-calorie diets, compared with higher-calorie regimens, reliably induced larger short-term (<6 months) weight losses, with deterioration of this benefit over the long term (>12 months). Few significant long-term differences in weight loss were observed for diets of varying macronutrient composition, although some regimens were found to have short-term advantages (e.g., low carbohydrate versus low fat). Progress in improving dietary adherence, which is critical to both short- and long-term weight loss, could result from greater efforts to identify behavioral and metabolic phenotypes among dieters.
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Affiliation(s)
- Ariana M. Chao
- University of Pennsylvania School of Nursing, Department of Biobehavioral Health Sciences, Philadelphia, Pennsylvania, USA
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kerry M. Quigley
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Thomas A. Wadden
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Associations of fat and carbohydrate intake with becoming overweight and obese: an 11-year longitudinal cohort study. Br J Nutr 2020; 124:715-728. [PMID: 32378502 DOI: 10.1017/s0007114520001579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The effects of macronutrient intake on obesity are controversial. This research aims to investigate the associations between macronutrient intake and new-onset overweight/obesity. The relationship between the consumption of carbohydrate and total fat and obesity was assessed by the multivariable Cox model in this 11-year cohort, which included 6612 adults (3291 men and 3321 women) who were free of overweight and obesity at baseline. The dietary intake was recorded using a 24-h recall method for three consecutive days. Moreover, substitution models were developed to distinguish the effects of macronutrient composition alteration from energy intake modification. During 7·5 person years (interquartile range 4·3, 10·8) of follow-up, 1807 participants became overweight or obese. After adjusting for risk factors, the hazard ratio (HR) of overweight/obesity in extreme quintiles of fat was 1·48 (quintile 5 v. quintile 1, 95 % CI 1·16, 1·89; Ptrend = 0·02) in women. Additionally, replacing 5 % of energy from carbohydrate with equivalent energy from fat was associated with an estimated 4·3 % (HR 1·043, 95 % CI 1·007, 1·081) increase in overweight/obesity in women. Moreover, dietary carbohydrate was inversely associated with overweight/obesity (quintile 5 v. quintile 1, HR 0·70, 95 % CI 0·55, 0·89; Ptrend = 0·02) in women. Total fat was related to a higher risk of overweight/obesity, whereas high carbohydrate intake was related to a lower risk of overweight/obesity in women, which was not observed in men.
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Westman EC, Yancy WS. Using a low-carbohydrate diet to treat obesity and type 2 diabetes mellitus. Curr Opin Endocrinol Diabetes Obes 2020; 27:255-260. [PMID: 32740047 DOI: 10.1097/med.0000000000000565] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW This study will provide a narrative review of the history of the clinical use of low-carbohydrate diets and give a practical example of how to implement a low-carbohydrate diet, with an emphasis on deprescribing medications. RECENT FINDINGS Low-carbohydrate diets have been used since the late 19th century to treat obesity and type 2 diabetes mellitus (T2DM). Recently, clinical research has validated the use of low-carbohydrate diets for individuals affected by obesity and T2DM, and these diets are included in several national clinical guidelines. Because medications are commonly used to treat hypertension and T2DM, special consideration must be made to monitor and reduce these medications to avoid overmedication. Clinic visits and home monitoring of blood pressure and glucose levels are important tools to alert clinicians that a reduction in medication levels may be indicated. SUMMARY Low-carbohydrate diets have been utilized clinically for many years to treat obesity and T2DM and can be used alongside effective monitoring to safely deprescribe dispensable medications for these diseases.
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Affiliation(s)
- Eric C Westman
- Division of General Internal Medicine, Department of Medicine, Duke University Medical Center
| | - William S Yancy
- Division of General Internal Medicine, Department of Medicine, Duke University Medical Center
- Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center
- Duke Diet and Fitness Center, Duke University Health System, Durham, North Carolina, USA
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Wu IX, Wang H, Zhu L, Chen Y, Wong CH, Mao C, Chung VC. Methodological quality of systematic reviews on interventions for osteoarthritis: a cross-sectional study. Ther Adv Musculoskelet Dis 2020; 12:1759720X20959967. [PMID: 33014149 PMCID: PMC7518002 DOI: 10.1177/1759720x20959967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 08/29/2020] [Indexed: 12/13/2022] Open
Abstract
Background Healthcare providers need reliable evidence for supporting the adoption of new interventions, of which the source of evidence often originates from systematic reviews (SRs). However, little assessment on the rigor of SRs related to osteoarthritis interventions has been conducted. This cross-sectional study aimed to evaluate the methodological quality and predictors among SRs on osteoarthritis interventions. Methods Four electronic databases (Cochrane Database of Systematic Reviews, MEDLINE, Embase, and PsycINFO) were searched, from 1 January 2008 to 10 October 2019. An SR was eligible if it focused on osteoarthritis interventions, and we performed at least one meta-analysis. Methodological quality was assessed using the validated AMSTAR 2 instrument. Multivariate regression analyses were conducted to assess predictors of methodological quality. Results In total, 167 SRs were included. The most SRs were non-Cochrane reviews (88.6%), and 54.5% investigated non-pharmacological interventions. Only seven (4.2%) had high methodological quality. Respectively, eight (4.8%), 25 (15.0%), and 127 (76.0%) SRs had moderate, low, and critically low quality. Main methodological weaknesses were as follows: only 16.8% registered protocol a priori, 4.2% searched literature comprehensively, 25.7% included lists of excluded studies with justifications, and 30.5% assessed risk of bias appropriately by considering allocation concealment, blinding of patients and assessors, random sequence generation and selective reported outcomes. Cochrane reviews [adjusted odds ratio (AOR) 251.5, 95% confidence interval (CI) 35.5-1782.6], being updates of previous SRs (AOR 3.9, 95% CI 1.1-13.7), and SRs published after 2017 (AOR 7.7, 95% CI 2.8-21.5) were positively related to higher methodological quality. Conclusion Despite signs of improvement in recent years, most of the SRs on osteoarthritis interventions have critically low methodological quality, especially among non-Cochrane reviews. Future SRs should be improved by conducting comprehensive literature search, justifying excluded studies, publishing a protocol, and assessing the risk of bias of included studies appropriately.
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Affiliation(s)
- Irene Xy Wu
- Xiangya School of Public Health, Central South University, Changsha, China
| | - Huan Wang
- Xiangya School of Public Health, Central South University, Changsha, China
| | - Lin Zhu
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Yancong Chen
- Xiangya School of Public Health, Central South University, Changsha, China
| | - Charlene Hl Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Rm 509, 5/F, Prince of Wales Hospital, Shatin, Hong Kong 999077, Hong Kong
| | - Chen Mao
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Vincent Ch Chung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Severe Metabolic Acidosis: A Case of Triple Hit with Ketogenic Diet, Vinegar, and Metformin in an Obese Patient. Case Rep Nephrol 2020; 2020:8861978. [PMID: 33014485 PMCID: PMC7512078 DOI: 10.1155/2020/8861978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 08/30/2020] [Accepted: 09/08/2020] [Indexed: 11/23/2022] Open
Abstract
Obesity is an epidemic with high burden of disease. It is directly proportional to increased risk of morbidity and mortality. Ketogenic diet and herbal supplements have recently gained popularity amongst patients struggling with weight loss. There are limited data available for most of these supplements contrary to the claims laid by the mainstream media. Due to lack of awareness, this patient population is at high risk of adverse effects. We present a case of severe acidosis secondary to ketogenic diet and acetic acid (vinegar) ingestion. The use of dietary acetic acid is usually well tolerated; however, in this case, the large quantities and presence of acute renal injury and metformin use may have worsened the acidosis. Severe ketosis in setting of ketogenic diets is a serious complication, which is infrequently reported in literature. Many of these diets and supplements may seem harmless, but as our case illustrates, when combined with other risk factors, patients can face serious adverse effects and even require hospitalization. It is imperative that such dietary practices are physician supervised to avoid complications. With the recent surge of over-the-counter weight loss supplements and ketogenic diets, physicians also need to engage in dietary discussion with patients when attempting to lose weight.
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Carbohydrate knowledge, dietary guideline awareness, motivations and beliefs underlying low-carbohydrate dietary behaviours. Sci Rep 2020; 10:14423. [PMID: 32879368 PMCID: PMC7468104 DOI: 10.1038/s41598-020-70905-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/03/2020] [Indexed: 12/31/2022] Open
Abstract
To explore the factors (including knowledge and attitude) influencing the decision to follow a low-carbohydrate diet (LCD) or not in a sample of the UK population. An online questionnaire was distributed electronically to adults who had either followed LCD or not (February-December 2019). Demographics and self-reported "LCD-status" (current, past and non-follower) were collected. Multivariable linear regression was used with carbohydrate knowledge, dietary guideline agreement and theory of planned behaviour (TPB) constructs (all as predictors) to explain the intention to follow a LCD (outcome). Respondents (n = 723, 71% women, median age 34; 85% white-ethnicity) were either following (n = 170, 24%) or had tried a LCD in the preceding 3 months (n = 184, 25%). Current followers had lower carbohydrate knowledge scores (1-2 point difference, scale - 11 to 11) than past and non-followers. A majority of current LCD followers disagreed with the EatWell guide recommendations "Base meals on potatoes, bread, rice and pasta, or other starchy carbohydrates. Choose whole grains where possible" (84%) and "Choose unsaturated oils and spreads and eat in small amounts such as vegetable, rapeseed, olive and sunflower oils" (68%) compared to past (37%, 10%, respectively) and non-followers (16%, 8%, respectively). Weight-loss ranked first as a motivation, and the internet was the most influencial source of information about LCDs. Among LCD-followers, 71% reported ≥ 5% weight loss, and over 80% did not inform their doctor, nurse, or dietitian about following a diet. Approximately half of LCD followers incorporated supplements to their diets (10% used multivitamin/mineral supplements), despite the restrictive nature of the diet. TPB constructs, carbohydrate knowledge, and guideline agreement explained 60% of the variance for the intention to follow a LCD. Attitude (std-β = 0.60), perceived behavioural control (std-β = 0.24) and subjective norm (std-β = 0.14) were positively associated with the intention to follow a LCD, while higher knowledge of carbohydrate, and agreeing with national dietary guidelines were both inversely associated (std-β = - 0.09 and - 0.13). The strongest primary reason behind UK adults' following a LCD is to lose weight, facilitated by attitude, perceived behavioural control and subjective norm. Higher knowledge about carbohydrate and agreement with dietary guidelines are found among people who do not follow LCDs.
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Churuangsuk C, Lean MEJ, Combet E. Lower carbohydrate and higher fat intakes are associated with higher hemoglobin A1c: findings from the UK National Diet and Nutrition Survey 2008-2016. Eur J Nutr 2020; 59:2771-2782. [PMID: 31686204 PMCID: PMC7413867 DOI: 10.1007/s00394-019-02122-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE Evidence of low-carbohydrate, high-fat diets (LCHF) for type 2 diabetes (T2DM) prevention is scarce. We investigated how carbohydrate intake relates to HbA1c and T2DM prevalence in a nationally representative survey dataset. METHODS We analyzed dietary information (4-day food diaries) from 3234 individuals aged ≥ 16 years, in eight waves of the UK National Diet and Nutrition Survey (2008-2016). We calculated LCHF scores (0-20, higher score indicating lower %food energy from carbohydrate, with reciprocal higher contribution from fat) and UK Dietary Reference Value (DRV) scores (0-16, based on UK dietary recommendations). Associations between macronutrients and diet scores and diabetes prevalence were analyzed (in the whole sample) using multivariate logistic regression. Among those without diabetes, analyses between exposures and %HbA1c (continuous) were analyzed using multivariate linear regression. All analyses were adjusted for age, sex, body mass index, ethnicity, smoking status, total energy intake, socioeconomic status and survey years. RESULTS In the overall study sample, 194 (6.0%) had diabetes. Mean intake was 48.0%E for carbohydrates, and 34.9%E for total fat. Every 5%E decrease in carbohydrate, and every 5%E increase in fat, was associated with 12% (95% CI 0.78-0.99; P = 0.03) and 17% (95% CI 1.02-1.33; P = 0.02) higher odds of diabetes, respectively. Each two-point increase in LCHF score is related to 8% (95% CI 1.02-1.14; P = 0.006) higher odds of diabetes, while there was no evidence for association between DRV score and diabetes. Among the participants without diagnosed diabetes (n = 3130), every 5%E decrease in carbohydrate was associated with higher %HbA1c by + 0.016% (95% CI 0.004-0.029; P = 0.012), whereas every 5%E increase in fat was associated with higher %HbA1c by + 0.029% (95% CI 0.015-0.043; P < 0.001). Each two-point increase in LCHF score is related to higher %HbA1c by + 0.010% (0.1 mmol/mol), while each two-point increase in the DRV score is related to lower %HbA1c by - 0.023% (0.23 mmol/mol). CONCLUSIONS Lower carbohydrate and higher fat intakes were associated with higher HbA1c and greater odds of having diabetes. These data do not support low(er) carbohydrate diets for diabetes prevention.
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Affiliation(s)
- Chaitong Churuangsuk
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, Room 2.22, Level 2, 10-16 Alexandra Parade, Glasgow, G31 2ER, UK
| | - Michael E J Lean
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, Room 2.22, Level 2, 10-16 Alexandra Parade, Glasgow, G31 2ER, UK
| | - Emilie Combet
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, Room 2.22, Level 2, 10-16 Alexandra Parade, Glasgow, G31 2ER, UK.
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Jebeile H, Grunseit AM, Thomas M, Kelly T, Garnett SP, Gow ML. Low-carbohydrate interventions for adolescent obesity: Nutritional adequacy and guidance for clinical practice. Clin Obes 2020; 10:e12370. [PMID: 32424989 DOI: 10.1111/cob.12370] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 12/14/2022]
Abstract
Low-carbohydrate dietary patterns are re-emerging as a popular method of weight reduction. However, their nutritional adequacy to meet the needs of growing adolescents should be considered. This study aimed to design theoretical low-carbohydrate meal plans for clinical use in the management of adolescent obesity and assess nutritional adequacy. Meal plans were created for three levels of carbohydrate restriction (≤30, ≤50 and ≤120 g/day) without energy, protein or total fat restriction. Nutrient analysis was conducted using the FoodWorks Australia Ltd software (databases: AUSNUT 2013, AusBrands 2017, AusFoods 2017, NUTTAB 2010, New Zealand FOODfiles 2016), and compared with Australian Nutrient Reference Values for male and female adolescents aged 14 to 18 years. All low-carbohydrate meal plans met the Recommended Dietary Intake, Adequate Intake or Estimated Average Requirements for most micronutrients at an energy intake of 6.3 to 7.2 MJ/day (1510-1730 kcal/day). The proportion of energy from saturated fat exceeded recommendations across all models (11.3%-17.1%). Dietary manipulation was required to minimize saturated fat and reach micronutrient adequacy, particularly for calcium in males and females, and iron for females. In practice, this may be challenging considering individual lifestyle and preferences. Therefore, the use of low-carbohydrate diets with adolescents should be monitored by a trained professional to ensure nutritional adequacy.
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Affiliation(s)
- Hiba Jebeile
- Children's Hospital Westmead Clinical School, The University of Sydney, Westmead, New South Wales, Australia
- The Children's Hospital at Westmead, Institute of Endocrinology and Diabetes, Westmead, New South Wales, Australia
| | - Alicia M Grunseit
- The Children's Hospital at Westmead, Weight Management Services and Department of Nutrition and Dietetics, Westmead, New South Wales, Australia
| | - Maddison Thomas
- Nutrition and Dietetics Group, School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Camperdown, New South Wales, Australia
| | - Tara Kelly
- HRB Clinical Research Facility, National University of Ireland, Galway, Ireland
- DDM Research Centre, Digital Diabetes Media, Coventry, UK
| | - Sarah P Garnett
- Children's Hospital Westmead Clinical School, The University of Sydney, Westmead, New South Wales, Australia
- The Children's Hospital at Westmead, Institute of Endocrinology and Diabetes, Westmead, New South Wales, Australia
- Kids Research, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Megan L Gow
- Children's Hospital Westmead Clinical School, The University of Sydney, Westmead, New South Wales, Australia
- The Children's Hospital at Westmead, Institute of Endocrinology and Diabetes, Westmead, New South Wales, Australia
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Foster S, Beck E, Hughes J, Grafenauer S. Whole Grains and Consumer Understanding: Investigating Consumers' Identification, Knowledge and Attitudes to Whole Grains. Nutrients 2020; 12:nu12082170. [PMID: 32708000 PMCID: PMC7468996 DOI: 10.3390/nu12082170] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/18/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022] Open
Abstract
Whole grains may assist in reducing risk of non-communicable disease, but consumption is limited in many countries. In Australia, the reasons for poor consumption are not well understood. The aim of this study was to investigate consumers' knowledge, attitudes and identification of whole grains, incorporating an exploration of factors influencing consumption, promotion and provision. An online semi-structured questionnaire was used to gather responses from 735 participants (61% complete responses). Although 92% of respondents consumed grains, only 8% reported an intake consistent with age and gender recommendations. Refined pasta and rice were the most frequently purchased grain foods followed by wholemeal/whole grain bread. Of whole grain foods, bread and breakfast cereals were consumed more frequently. However, overall, participants did not prioritise consumption of whole grains. Despite this, 93% of participants had seen food packaging information drawing attention to whole grain content, with a high proportion describing whole grain as less processed (72%) or high in dietary fibre (67%). Two-thirds were aware of health benefits but stated that if they had further information, they would be more likely to swap to whole grain. Further education, increasing exposure, accessibility and extensive promotion of whole grain health benefits are required to facilitate whole grain consumption. Furthermore, removing the negative stigma associated with carbohydrate foods, including grains, will be necessary to improve consumption.
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Affiliation(s)
- Shara Foster
- School of Medicine, University of Wollongong, Northfields Avenue, Wollongong 2522, Australia; (S.F.); (E.B.)
| | - Eleanor Beck
- School of Medicine, University of Wollongong, Northfields Avenue, Wollongong 2522, Australia; (S.F.); (E.B.)
- Illawarra Health & Medical Research Institute, Northfields Avenue, Wollongong 2552, Australia
| | - Jaimee Hughes
- Grains & Legumes Nutrition Council, 1 Rivett Rd, North Ryde 2113, Australia;
| | - Sara Grafenauer
- School of Medicine, University of Wollongong, Northfields Avenue, Wollongong 2522, Australia; (S.F.); (E.B.)
- Grains & Legumes Nutrition Council, 1 Rivett Rd, North Ryde 2113, Australia;
- Correspondence: ; Tel.: +61-401-265-142
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Wang HH, Lee DK, Liu M, Portincasa P, Wang DQH. Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome. Pediatr Gastroenterol Hepatol Nutr 2020; 23:189-230. [PMID: 32483543 PMCID: PMC7231748 DOI: 10.5223/pghn.2020.23.3.189] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/17/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.
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Affiliation(s)
- Helen H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Dong Ki Lee
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Piero Portincasa
- Department of Biomedical Sciences and Human Oncology, Clinica Medica "A. Murri", University of Bari Medical School, Bari, Italy
| | - David Q.-H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
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Storman M, Storman D, Jasinska KW, Swierz MJ, Bala MM. The quality of systematic reviews/meta-analyses published in the field of bariatrics: A cross-sectional systematic survey using AMSTAR 2 and ROBIS. Obes Rev 2020; 21:e12994. [PMID: 31997545 DOI: 10.1111/obr.12994] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/24/2019] [Accepted: 12/09/2019] [Indexed: 12/17/2022]
Abstract
High-quality systematic reviews (SR) and meta-analyses (MA) are considered to be reliable sources of information. This study aims to assess the quality of studies published as SR or MA in the field of bariatrics in 2016 and 2017. We identified SR and MA in the field of bariatrics by searching electronic databases (MEDLINE, Embase, and Cochrane Database of Systematic Reviews). Eligible studies were those identified as SR/MA in the title/abstract, which aimed to assess any outcome in patients with morbid obesity undergoing or scheduled to undergo bariatric surgery. Two authors independently reviewed all titles and abstracts, assessed full texts of potentially eligible studies, and assessed the quality of included studies. Any discrepancies were resolved by the third reviewer. We evaluated the quality and risk of bias of each SR/MA using AMSTAR 2 checklist and ROBIS tool, respectively. Seventy-eight of 4236 references met inclusion criteria and were assessed for their quality/risk of bias. The methodological quality of 99% of all papers was classified as "critically low." A total of 6% of the studies were at low risk of bias, and 78% were assessed as being at high risk of bias. The methodological quality of studies published in 2016 and 2017 as SR/MA is highly unsatisfactory.
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Affiliation(s)
- Monika Storman
- Systematic Reviews Unit, Jagiellonian University Medical College, Krakow, Poland
| | - Dawid Storman
- Department of Hygiene and Dietetics, Jagiellonian University Medical College, Krakow, Poland
| | - Katarzyna W Jasinska
- Students' Research Group, Systematic Reviews Unit, Jagiellonian University Medical College, Krakow, Poland
| | - Mateusz J Swierz
- Department of Hygiene and Dietetics, Jagiellonian University Medical College, Krakow, Poland
| | - Malgorzata M Bala
- Systematic Reviews Unit, Jagiellonian University Medical College, Krakow, Poland.,Department of Hygiene and Dietetics, Jagiellonian University Medical College, Krakow, Poland.,Chair of Epidemiology and Preventive Medicine, Jagiellonian University Medical College, Krakow, Poland
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64
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The Effects of Different Degrees of Carbohydrate Restriction and Carbohydrate Replacement on Cardiometabolic Risk Markers in Humans-A Systematic Review and Meta-Analysis. Nutrients 2020; 12:nu12040991. [PMID: 32252374 PMCID: PMC7230871 DOI: 10.3390/nu12040991] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/02/2022] Open
Abstract
Low-carbohydrate diets (LCDs) often differ in their diet composition, which may lead to conflicting results between randomized controlled trials. Therefore, we aimed to compare the effects of different degrees of carbohydrate (CHO) restriction on cardiometabolic risk markers in humans. The experimental LCDs of 37 human trials were classified as (1) moderate-low CHO diets (<45–40 E%, n = 13), (2) low CHO diets (<40–30 E%, n = 16), and (3) very-low CHO diets (<30–3 E%; n = 8). Summary estimates of weighted mean differences (WMDs) in selected risk markers were calculated using random-effect meta-analyses. Differences between the LCD groups were assessed with univariate meta-regression analyses. Overall, the LCDs resulted in significant weight loss, reduced diastolic blood pressure BP, and increased total cholesterol and high-density lipoprotein cholesterol (HDL-C), without significant differences between the three LCD groups. Higher low-density lipoprotein cholesterol (LDL-C) concentrations were found with the very-low CHO diets compared to the moderate-low CHO diets. Decreases in triacylglycerol (TAG) concentrations were more pronounced with the low and very-low CHO diets, compared to the moderate-low CHO diets. Substitution of CHO by mainly saturated fatty acids (SFAs) increased total cholesterol, LDL-C, and HDL-C concentrations. Except for LDL-C and TAGs, effects were not related to the degree of CHO restriction. Potential effects of nutrient exchanges should be considered when following LCDs.
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65
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Churuangsuk C, Lean MEJ, Combet E. Low and reduced carbohydrate diets: challenges and opportunities for type 2 diabetes management and prevention. Proc Nutr Soc 2020; 79:1-16. [PMID: 32131904 DOI: 10.1017/s0029665120000105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Low-carbohydrate diets (LCD) have been promoted for weight control and type 2 diabetes (T2D) management, based on an emerging body of evidence, including meta-analyses with an indication of publication bias. Proposed definitions vary between 50 and 130 g/d, or <10 and <40 % of energy from carbohydrate, with no consensus on LCD compositional criteria. LCD are usually followed with limited consideration for other macronutrients in the overall diet composition, introducing variance in the constituent foods and in metabolic responses. For weight management, extensive evidence supports LCD as a valid weight loss treatment, up to 1-2 years. Solely lowering carbohydrate intake does not, in the medium/long term, reduce HbA1c for T2D prevention or treatment, as many mechanisms interplay. Under controlled feeding conditions, LCD are not physiologically or clinically superior to diets with higher carbohydrates for weight-loss, fat loss, energy expenditure or glycaemic outcomes; indeed, all metabolic improvements require weight loss. Long-term evidence also links the LCD pattern to increased CVD risks and mortality. LCD can lead to micronutrient deficiencies and increased LDL-cholesterol, depending on food selection to replace carbohydrates. Evidence is limited but promising regarding food choices/sources to replace high-carbohydrate foods that may alleviate the negative effects of LCD, demanding further insight into the dietary practice of medium to long term LCD followers. Long-term, high-quality studies of LCD with different food sources (animal and/or plant origins) are needed, aiming for clinical endpoints (T2D incidence and remission, cardiovascular events, mortality). Ensuring micronutrient adequacy by food selection or supplementation should be considered for people who wish to pursue long-term LCD.
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Affiliation(s)
- Chaitong Churuangsuk
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, GlasgowG31 2ER, UK
- Division of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand
| | - Michael E J Lean
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, GlasgowG31 2ER, UK
| | - Emilie Combet
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, GlasgowG31 2ER, UK
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66
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Khanam UA, Rennie DC, Davis K, Lawson JA. Are Dietary Factors Associated with Lung Function in Canadian Adults? CAN J DIET PRACT RES 2020; 81:28-36. [PMID: 31512487 DOI: 10.3148/cjdpr-2019-023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Purpose: The purpose of this study was to explore the impact of dietary factors and biomarkers on lung function among Canadian adults (18-79 years). Methods: Our data source was the Canadian Health Measures Survey Cycle-3, which included 3397 adults. The household and clinic questionnaires and physical measures were used to assess individual dietary factors, modified Mediterranean Diet Scores, and biomarkers. Results: The overall mean percent predicted values for FVC and FEV1 were 97% and 95%, respectively. While somewhat inconsistent between outcomes, higher lung function was associated with bean, grain, milk, fruit, and vegetable consumption, whereas lower lung function was associated with egg and potato consumption. Among the biomarkers, vitamin D, chloride, total serum protein, and red blood cell folate were associated with higher lung function, whereas C-reactive protein and vitamin B12 was associated with lower lung function. Conclusion: Our study provides support for an association between some dietary factors and lung function, though not entirely consistent between a specific dietary factor and the outcomes studied (FVC, FEV1, FVC/FEV1, and FEF25%-75%). The associations between a specific biomarker and lung function were more consistent (i.e., observed with a larger number of lung function outcomes) than were the dietary factors.
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Affiliation(s)
- Ulfat A Khanam
- College of Medicine, University of Saskatchewan, Saskatoon, SK
| | - Donna C Rennie
- College of Nursing, University of Saskatchewan, Saskatoon, SK.,Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, SK
| | - Karen Davis
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK
| | - Joshua A Lawson
- College of Medicine, University of Saskatchewan, Saskatoon, SK.,Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, SK
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67
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Hasan MM, Zhang M, Beal M, Ghomrawi HMK. An umbrella review comparing computer-assisted and conventional total joint arthroplasty: quality assessment and summary of evidence. BMJ SURGERY, INTERVENTIONS, & HEALTH TECHNOLOGIES 2020; 2:e000016. [PMID: 35047783 PMCID: PMC8749275 DOI: 10.1136/bmjsit-2019-000016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 11/22/2019] [Accepted: 12/18/2019] [Indexed: 01/02/2023] Open
Abstract
Background Systematic reviews (SRs) of computer-assisted (CA) total knee arthroplasty (TKA) and total hip arthroplasty (THA) report conflicting evidence on its superiority over conventional surgery. Little is known about the quality of these SRs; variability in their methodological quality may be a contributing factor. We evaluated the methodological quality of all published SRs to date, summarized and examined the consistency of the evidence generated by these SRs. Methods We searched four databases through December 31, 2018. A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2) was applied to assess the methodological quality. Evidence from included meta-analyses on functional, radiological and patient-safety outcomes was summarized. The corrected covered area was calculated to assess the overlap between SRs in including the primary studies. Results Based on AMSTAR 2, confidence was critically low in 39 of the 42 included SRs and low in 3 SRs. Low rating was mainly due to failure in developing a review protocol (90.5%); providing a list of excluded studies (81%); accounting for risk of bias when discussing the results (67%); using a comprehensive search strategy (50%); and investigating publication bias (50%). Despite inconsistency between SR findings comparing functional, radiological and patient safety outcomes for CA and conventional procedures, most TKA meta-analyses favored CA TKA, whereas most THA meta-analyses showed no difference. Moderate overlap was observed among TKA SRs and high overlap among THA SRs. Conclusions Despite conclusions of meta-analyses favoring CA arthroplasty, decision makers adopting this technology should be aware of the low confidence in the results of the included SRs. To improve confidence in future SRs, journals should consider using a methodological assessment tool to evaluate the SRs prior to making a publication decision.
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Affiliation(s)
- Mohamed Mosaad Hasan
- Institute of Public Health and Medicine, Northwestern University, Chicago, Illinois, USA
| | - Manrui Zhang
- Department of Medical Social Sciences, Northwestern University, Chicago, Illinois, USA
| | - Matthew Beal
- Orthopedic Surgery, Northwestern University, Chicago, Illinois, USA
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68
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Effects of a low-carbohydrate diet on performance and body composition in trained cyclists. NUTR HOSP 2019; 36:1384-1388. [PMID: 31718211 DOI: 10.20960/nh.02762] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Introduction Previous evidence suggests that low-carbohydrate diets may improve body composition and performance relative to body weight in endurance athletes. This has been the first study that has attempted to evaluate the utility of low-carbohydrate diets in a sample of eleven trained and experienced road cyclists who consumed 10% of their caloric intake in the form of carbohydrates during four weeks while maintaining a neutral energy balance (50 kcal/kg/day). Body composition was evaluated through an electrical impedance assessment before and after the intervention while maximal power output (5 and 20 min) was measured on a bike trainer by following a standardized protocol and in the same room conditions for all the participants. The study was performed during the preseason, when the subjects could abstain from performing high-intensity workouts. The participants, eleven men aged 31 ± 5 years, performed four weekly 150 min training sessions at submaximal intensities and received nutritional support from a certified sport nutritionist. The intervention resulted in reduced total weight (-2.51 kg) and body fat percentage (2.42%), and improved relative power (+0.2 w/kg for 20 min and +0.25 w/kg for 5 min) values while absolute power remained unchanged. The results suggest that low-carbohydrate diets could be used in order to induce changes in body composition and improve relative power during the preseason. However, future research with larger sample sizes and a control group is needed in order to validate the results.
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69
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Najjar RS, Feresin RG. Plant-Based Diets in the Reduction of Body Fat: Physiological Effects and Biochemical Insights. Nutrients 2019; 11:nu11112712. [PMID: 31717463 PMCID: PMC6893503 DOI: 10.3390/nu11112712] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 02/07/2023] Open
Abstract
Obesity affects over one-third of Americans and increases the risk of cardiovascular disease and type II diabetes. Interventional trials have consistently demonstrated that consumption of plant-based diets reduces body fat in overweight and obese subjects, even when controlling for energy intake. Nonetheless, the mechanisms underlying this effect have not been well-defined. This review discusses six major dietary mechanisms that may lead to reduced body fat. These include (1) reduced caloric density, (2) improved gut microbiota symbiosis, (3) increased insulin sensitivity, (4) reduced trimethylamine-N-oxide (TMAO), (5) activation of peroxisome proliferator-activated receptors (PPARs), and (6) over-expression of mitochondrial uncoupling proteins. Collectively, these factors improve satiety and increase energy expenditure leading to reduced body weight.
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70
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Berger N, Cummins S, Smith RD, Cornelsen L. Recent trends in energy and nutrient content of take-home food and beverage purchases in Great Britain: an analysis of 225 million food and beverage purchases over 6 years. BMJ Nutr Prev Health 2019; 2:63-71. [PMID: 33235959 PMCID: PMC7664498 DOI: 10.1136/bmjnph-2019-000036] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/21/2019] [Accepted: 07/06/2019] [Indexed: 11/12/2022] Open
Abstract
Introduction In recent years, there has been an increased focus on developing a coherent obesity policy in the UK, which has led to various national policy initiatives aimed at improving population diet. We sought to determine whether there have been concurrent changes in trends in the nutrient content of take-home food and beverage purchases within this policy environment. Methods We used 2012–2017 data from the UK Kantar Fast-Moving Consumer Goods (FMCG) panel, a nationally representative panel study of food and beverages bought by British households and brought into the home (n≈32 000 per year). Households used hand-held barcode scanners to report over 225 million product-level purchases of food and beverages, for which nutritional information was obtained. We estimated daily per capita purchases of energy and nutrients from 32 healthier and less healthy food groups defined using the nutrient profiling model used by the UK Department of Health. Results From 2012 to 2017, daily purchases of energy from food and beverages taken home decreased by 35.4 kcal (95% CI 25.5 to 45.2) per capita. This is explained by moderate decreases in the purchase of products with high contents in carbohydrate (−13.1 g (−14.4 to –11.8)) and sugar (−4.4 g (−5.1 to –3.7)), despite small increases in protein (1.7 g (1.4 to 2.1)) and saturated fat (0.4 g (0.2 to 0.6)). Food and beverage purchases exceeded daily reference intake values in fat (on average +6%), saturated fat (+43%), sugar (+16%) and protein (+28%) across all years. Although substitutions between individual food groups were large in energy and nutrients purchased, the heterogeneity of these patterns resulted in modest overall changes. Conclusion There have been small declines in the purchase of less healthy food products, which translated to a small reduction of total energy and sugar purchases taken home. However, the rate of change needs to be accelerated in order to substantially reduce the health risks of poor diets, suggesting that more radical policies may be needed to attain larger population effects.
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Affiliation(s)
- Nicolas Berger
- Population Health Innovation Lab, Department of Public Health, Environments and Society, London School of Hygiene and Tropical Medicine, London, UK
| | - Steven Cummins
- Population Health Innovation Lab, Department of Public Health, Environments and Society, London School of Hygiene and Tropical Medicine, London, UK
| | - Richard D Smith
- College of Medicine and Health, University of Exeter, Exeter, UK
| | - Laura Cornelsen
- Population Health Innovation Lab, Department of Public Health, Environments and Society, London School of Hygiene and Tropical Medicine, London, UK
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71
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Churuangsuk C, Griffiths D, Lean MEJ, Combet E. Impacts of carbohydrate-restricted diets on micronutrient intakes and status: A systematic review. Obes Rev 2019; 20:1132-1147. [PMID: 31006978 DOI: 10.1111/obr.12857] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/19/2019] [Accepted: 03/05/2019] [Indexed: 12/20/2022]
Abstract
A systematic review of published evidence on micronutrient intake/status with carbohydrate-restricted diets (CRD) was conducted in Web of Science, Medline, Embase, Scopus, CENTRAL, and ClinicalTrials.gov up to October 2018. We identified 10 studies: seven randomized controlled trials (RCTs) ("Atkins"-style, n = 5; "Paleolithic" diets, n = 2), two Atkins-style noncontrolled trials and one cross-sectional study. Prescribed carbohydrate varied 4% to 34% of energy intake. Only one noncontrolled trial prescribed multivitamin supplements. Dietary intakes/status were reported over 2 to 104 weeks, with weight losses from 2 to 9 kg. No diagnoses of deficiency were reported. Intakes of thiamine, folate, magnesium, calcium, iron, and iodine all decreased significantly (-10% to -70% from baseline) with any CRD types. Atkins diet trials (n = 6; 4%-34%E carbohydrate) showed inconsistent changes in vitamin A, E, and β-carotene intakes, while a single "Paleolithic" diet trial (28%E carbohydrate) reported increases in these micronutrients. One other "Paleolithic" diet (30%E carbohydrate) reported a rise in moderate iodine deficiency from 15% to 73% after 6 months. In conclusion, few studies have assessed the impacts of CRD on micronutrients. Studies with different designs point towards reductions in several vitamins and minerals, with potential risk of micronutrient inadequacies. Trial reporting standards are expected to include analysis of micronutrient intake/status. Micronutrients in foods and/or supplements should be considered when designing, prescribing or following CRDs.
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Affiliation(s)
- Chaitong Churuangsuk
- Human Nutrition, School of Medicine Dentistry and Nursing, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Daniel Griffiths
- Human Nutrition, School of Medicine Dentistry and Nursing, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Michael E J Lean
- Human Nutrition, School of Medicine Dentistry and Nursing, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Emilie Combet
- Human Nutrition, School of Medicine Dentistry and Nursing, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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72
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Holzapfel C. [Update on weight loss in persons with type 2 diabetes mellitus]. MMW Fortschr Med 2019; 161:52-56. [PMID: 31183696 DOI: 10.1007/s15006-019-0622-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Christina Holzapfel
- Institut für Ernährungsmedizin, Klinikum rechts der Isar Technische Universität München, Georg-Brauchle-Ring 62, D-80992, München, Deutschland.
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73
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Huang H, Liao D, Dong Y, Pu R. Clinical effectiveness of quercetin supplementation in the management of weight loss: a pooled analysis of randomized controlled trials. Diabetes Metab Syndr Obes 2019; 12:553-563. [PMID: 31114281 PMCID: PMC6497115 DOI: 10.2147/dmso.s199830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 02/28/2019] [Indexed: 01/08/2023] Open
Abstract
Purpose: The previous investigations which considered the possible effect of the quercetin supplementation for overweight and obesity have led to inconsistent results. Here, we aimed to evaluate the effects of quercetin on weight loss using a meta-analysis of randomized controlled clinical trials (RCTs). Methods: Relevant studies were systematically searched from the MEDLINE, EMBASE, Google Scholar, and Scopus databases. RCTs that investigated the effects of quercetin on weight loss in humans were included for quality assessment, meta-analyses, sensitivity analysis, subgroup analyses, and publication bias assessment. Effect size was expressed as weighted mean difference (WMD) and 95% CI by using a random-effects model. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to rate the level of evidence. Results: Nine RCTs (11 treatment arms) with 525 participants were finally included for data pooling. Our meta-analysis revealed that daily quercetin supplementation did not significantly affect the body weight (WMD: -0.35 kg, 95% CI: -2.03, 1.33; P=0.68), body mass index (WMD: -0.04 kg/m2, 95% CI: -0.54, 0.45; P=0.87), waist circumference (WMD: -0.37 cm, 95% CI: -1.81, 1.06; P=0.61), and waist to hip ratio (WMD: -0.01, 95% CI: -0.03, 0.01; P=0.48). Subgroup analysis could not identify factors significantly influencing these parameters. These results were robust in sensitivity analysis, and no significant publication bias was found. Conclusion: The current evidence suggests that quercetin intake did not show a notably favorable effect on weight loss. Future well-designed and long-term clinical trials are required to confirm these results.
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Affiliation(s)
- Haohai Huang
- Department of Clinical Pharmacy, Dongguan Third People’s Hospital, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, Dongguan, Guangdong, People’s Republic of China
- Correspondence: Haohai HuangDepartment of Clinical Pharmacy, Dongguan Third People’s Hospital, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, No.1, Huangzhou Xianglong Road of Shilong Town, Dongguan, Guangdong523326, People’s Republic of ChinaTel +86 769 8136 8831Fax +86 769 8136 8802Email
| | - Dan Liao
- Department of Gynaecology, Dongguan Third People’s Hospital, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, Dongguan, Guangdong, People’s Republic of China
| | - Yong Dong
- Department of Cancer Center, Dongguan Third People‘s Hospital, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, Dongguan, Guangdong, People’s Republic of China
| | - Rong Pu
- Department of Clinical Laboratory, Dongguan Third People’s Hospital, Affiliated Dongguan Shilong People‘s Hospital of Southern Medical University, Dongguan, Guangdong, People’s Republic of China
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Starchy Carbohydrates in a Healthy Diet: The Role of the Humble Potato. Nutrients 2018; 10:nu10111764. [PMID: 30441846 PMCID: PMC6267054 DOI: 10.3390/nu10111764] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 10/26/2018] [Accepted: 11/06/2018] [Indexed: 01/06/2023] Open
Abstract
Potatoes have been an affordable, staple part of the diet for many hundreds of years. Recently however, there has been a decline in consumption, perhaps influenced by erroneous reports of being an unhealthy food. This review provides an overview of the nutritional value of potatoes and examines the evidence for associations between potato consumption and non-communicable diseases. Potatoes are an important source of micronutrients, such as vitamin C, vitamin B6, potassium, folate, and iron and contribute a significant amount of fibre to the diet. However, nutrient content is affected by cooking method; boiling causes leaching of water-soluble nutrients, whereas frying can increase the resistant starch content of the cooked potato. Epidemiological studies have reported associations between potato intake and obesity, type 2 diabetes and cardiovascular disease. However, results are contradictory and confounded by lack of detail on cooking methods. Indeed, potatoes have been reported to be more satiating than other starchy carbohydrates, such as pasta and rice, which may aid weight maintenance. Future research should consider cooking methods in the study design in order to reduce confounding factors and further explore the health impact of this food.
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