Effects of a 6-month, low-carbohydrate diet on glycaemic control, body composition, and cardiovascular risk factors in patients with type 2 diabetes: An open-label randomized controlled trial

Low carbohydrate high fat-diet in real life; A descriptive analysis of cardiovascular risk factors

Aims

Low Carbohydrate High Fat (LCHF) diets are popular for weight loss or glucose control. The main source of energy in such diets is fat but the composition of nutrients varies This study aims to investigate dietary variations in a real-world LCHF population and its associations with cardiovascular risk factors.

Methods

We recruited 100 volunteers who considered themselves adherent to a LCHF diet. Their last 14 days of dietary intake was assessed using diet history interviews. Validation of energy intake against expenditure was made using activity monitors. Predictive variables for the linear regression models were selected using stepwise bidirectional assessment of Akaike information criterion (AIC).

Results

Energy intake (E%) from carbohydrates was low, 8.7 E%, and fat was the main replacement. Dietary cholesterol was associated with higher total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL). Dietary sodium intake was associated with higher blood pressure. Protein intake was associated with lower diastolic blood pressure but also with lower HDL. The intake of dietary fibre was associated with lower LDL and total cholesterol but with higher hemoglobin A1c (HbA1c). The intake of carbohydrates and saturated fatty acids (SFA) was not associated with any of the outcome variables.

Conclusion

In this LCHF population, variations in intake of carbohydrates and saturated fatty acids could not predict any aspects of the cardiovascular risk profile. Lower fibre intake and higher cholesterol and sodium intake predicted a less favorable cardiovascular risk profile.

The dual challenge of diabesity: pathophysiology, management, and future directions

Diabesity, the concurrent occurrence of obesity and type-2 diabetes mellitus (T2DM), represents a pressing global health challenge characterized by intricate pathophysiological mechanisms and a wide range of associated comorbidities. Central to its development are insulin resistance, metabolic syndrome, and chronic low-grade inflammation mediated by dysregulated adipokine secretion and systemic metabolic dysfunction. These mechanisms underpin the progression of diabesity and its complications, including cardiovascular disease and hypertension. Management strategies encompass lifestyle interventions focusing on tailored dietary modifications and structured physical activity, pharmacological treatments targeting both glycemic control and weight loss, and surgical interventions such as bariatric surgery, which have demonstrated efficacy in achieving durable outcomes. Clinical trials and meta-analyses underscore the comparative advantages of different treatment modalities in terms of efficacy, safety, and sustainability. Moreover, long-term follow-up studies emphasize the critical need for sustained multidisciplinary interventions to prevent relapse and enhance patient outcomes. Future advancements in management include exploring precision medicine approaches that integrate individual metabolic profiles, lifestyle factors, and emerging therapeutic innovations. A multidisciplinary approach combining advanced therapeutic strategies and patient-centered care remains pivotal for optimizing management and improving prognoses for individuals with diabesity. This review highlights the complex interplay between obesity and T2DM, offering comprehensive insights into their pathophysiology, clinical presentation, and management paradigms.

Nutritional Approach to Diabetic Sarcopenia: A Comprehensive Review

PURPOSE OF THE REVIEW

The aim of this review is to discuss and evaluate diabetic sarcopenia (DS) and its relationship with nutrition by discussing the mechanisms of diabetic sarcopenia in detail and comprehensively reviewing the literature.

RECENT FINDINGS

Type 2 diabetes (T2DM) affects approximately 25% of people aged 50 years and over and indicates a significant the cost of health for the elderly. Nutrition is an important part of these treatment approaches, and in this review, the literature was comprehensively reviewed, focusing on understanding the mechanisms of DS and discussing its relationship with nutrition. A comprehensive search was conducted on Web of Science, Google Scholar, Scopus, Science Direct, and PubMed from inception up to July 2024. The aim of nutritional treatment for DS is to improve muscle mass, muscle strength and physical performance while improving diabetes-related metabolic risk and glucose levels. In this context, it is important to determine energy intake in individuals with DS according to calorie intake exceeding 30 kcal/kg. For these individuals, a protein intake of at least 1-1.2 g/kg/day is recommended, with an emphasis on the number and timing of meals and a nutritional pattern rich in branched chain amino acids (BCAA). In addition, it is important to adopt a diet rich in antioxidants and to choose diet patterns that contain sufficient levels of macro and micronutrients. The Mediterranean diet model can be a good diet option for individuals with DS. Comprehensive studies in this field are needed so that clinicians can make specific dietary recommendations for DS.

Structural Concepts, Definition, Classification, and Macronutrient and Food Composition of Carbohydrate-Restricted Diets for Individuals with Type 2 Diabetes Mellitus: A Scoping Review

Objective: This study aimed to review the structural concepts, definition, classification, and macronutrient and food composition of carbohydrate-restricted diets (CRDs) for individuals with type 2 diabetes mellitus (T2DM). Methods: A scoping review was conducted following Joanna Briggs Institute guidelines. Searches were performed in Scopus, PubMed, Web of Science, and Embase, including texts published in Portuguese, English, and Spanish. Official documents from governments, regulatory agencies, and international diabetes organizations were also consulted. Results: In total, 79 articles and 17 official documents were analyzed. The following structural concept was identified: restricted carbohydrate intake decreases the need for endogenous and exogenous insulin, contributing to the maintenance of glycemic control, and justifies its consideration among the nutritional therapy options for individuals with T2DM. CRDs varied in definition, classification, and macronutrient composition. Studies failed to provide detailed information on the food composition of diets, precluding an in-depth understanding of metabolic effects. The existence of several approaches with varying recommendations makes it difficult to generalize the results. International CRD guidelines for T2DM adopt divergent definitions, compromising interpretation, recommendation, and even adherence. Conclusions: Although the concept of CRDs justifies their adoption within the nutritional therapy choices for T2DM, the multiple denominations can hinder understanding and comparison between studies. The lack of information on food composition and carbohydrate types compromises the assessment of the effects and adherence to CRD-based nutritional interventions. We emphasize the need for methodologically consistent studies that evaluate CRDs based on fresh and minimally processed foods with a low glycemic index to support official diabetes guidelines and organizations.

Study protocol, menu design, and rationale for a study testing the effects of a whole fruit-rich diet on glycemic control, liver fat, pancreatic fat, and cardiovascular health in adults with type 2 diabetes

Dietary interventions such as very-low-calorie diets and low-carbohydrate diets can improve glycemic control and even induce type 2 diabetes (T2D) remission. However, less is known about the effects of carbohydrate-rich whole foods, such as whole fruit, in people with T2D. Therefore, the aim of this pilot study is to investigate the effects of a whole fruit-rich diet on glycemic control, ectopic fat, and cardiovascular risk factors in adults with T2D. In this pilot study, sixteen adults aged 20 to 70 years with insulin-independent T2D for ≤6 years will complete a 12-week controlled-feeding intervention while maintaining their weight. During the ramp-up phase (weeks 1-4), participants progressively consume more whole fruit. During weeks 5 to 12, participants eat a fruit-rich Mediterranean diet providing 50% of calories as whole fruit (∼16.4 servings/day). All outcomes are measured at weeks 0, 4, and 12. The primary outcome is glycemic control, assessed hierarchically by whether participants achieve nondiabetic glucose concentrations without antihyperglycemic medications; the total dose of antihyperglycemic medications; mean glucose during a three-hour oral glucose tolerance test; and mean 24-hour glucose from continuous glucose monitoring. Secondary outcomes include intrahepatic lipid, pancreatic fat, blood pressure, heart rate, and serum lipids. We hypothesize that a fruit-rich diet will improve glycemic control, reduce the need for antihyperglycemic medications, decrease ectopic fat, and improve cardiovascular risk factors. This novel study will help determine the effects of a whole fruit-rich diet on glycemic control and liver fat and whether diabetes remission may be possible without losing weight. This study was registered at ClinicalTrials.gov (NCT03758742).

Navigating the Spectrum of 4 Evidence-Based Nutrition Options for Type 2 Diabetes Management

CONTEXT

Type 2 diabetes mellitus is a complex, pervasive disease that creates a health and financial burden. The goal is to head off progression to insulin requirement, and dietary changes have been recognized as a first-line intervention in the treatment protocol. Four evidence-based nutritional options are reviewed and their benefits for metabolic consequences.

EVIDENCE ACQUISITION

We conducted a comprehensive search of relevant literature using the PubMed database for recent systematic reviews, meta-analyses, and original research articles.

EVIDENCE SYNTHESIS

The Mediterranean and plant-based diets have demonstrated benefits for the prevention and treatment of diabetes, weight reduction, lipid improvements, and overall cardiovascular risk reduction. A low carbohydrate diet is another viable option for hemoglobin A1c (HbA1c) reduction, though it is not as uniformly defined and is difficult to maintain long term. The ketogenic diet is similarly very restrictive and produces significant HbA1c reductions.

CONCLUSION

Type 2 diabetes prevention and treatment is crucial in this widespread disease. The first-line treatment is lifestyle modifications with dietary interventions being at the forefront. With a unique clinical model and a variety of dietary options, our program strives for individualized evidence-based care. Nutritional modifications are the best initial approaches to overcoming insulin resistance and hyperinsulinemia. All dietary modifications, like any medical intervention, require education on benefits vs risks.

The effects of low-carbohydrate diet on glucose and lipid metabolism in overweight or obese patients with T2DM: a meta-analysis of randomized controlled trials

Background

The dual burden of Type 2 Diabetes Mellitus (T2DM) and obesity is a critical public health issue. Low-carbohydrate diets have emerged as a potential intervention, yet clinical evidence remains inconclusive.

Purpose

This meta-analysis assesses the impact of low-carbohydrate diets on metabolic profiles in overweight or obese T2DM patients, aiming to guide clinical practice.

Methods

A systematic review identified randomized clinical trials (RCTs) comparing low-carbohydrate diets to control diets in T2DM patients from PubMed, Embase, and the Cochrane Library databases up to April 2023.

Results

Seventeen RCTs, encompassing 1,197 participants, demonstrated that low-carbohydrate diets significantly improved HbA1c levels and fasting plasma glucose (mean difference [MD] = -0.36, 95% CI -0.44 to -0.29, p < 0.00001; MD = -10.71, 95% CI -14.39 to -7.03, p < 0.00001). They also reduced triglycerides and increased HDL cholesterol (MD = -19.91, 95% CI -28.83 to -10.99, p < 0.00001; MD = 2.49, 95% CI 1.07-3.91, p = 0.0006), without affecting LDL and total cholesterol. Weight loss, reduced BMI, lower diastolic blood pressure, and decreased waist circumference were additional benefits.

Conclusion

Low-carbohydrate diets may enhance glycemic control and lipid profiles in overweight or obese T2DM patients, warranting consideration in T2DM management. However, the variability in diet definitions and methodologies underscores the necessity for further research to standardize dietary guidelines and evaluate long-term effects.

Effect of Zinc Supplementation on Lipid Profile and Body Composition in Patients with Type 2 Diabetes Mellitus: A GRADE-Assessed Systematic Review and Dose-Response Meta-analysis

The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to investigate the overall effects of zinc supplementation on lipid profile and body composition such as body weight (BW), body mass index (BMI), triglycerides (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) in patients with type 2 diabetes mellitus (T2DM). Scopus, Web of Science, PubMed, and Embase databases were searched from inception through October, 2023. The I2 and Cochran's Q tests were used to assess heterogeneity between studies. Nineteen RCTs (n = 1357 participants) were included in the meta-analysis. Zinc supplementation significantly reduced TG (WMD = - 17.41 mg/dL; 95% CI: - 22.60, - 12.22; P < 0.001), TC (WMD: - 19.60 mg/dL; 95% CI: - 28.46, - 10.73, P < 0.001), LDL-C (WMD = - 8.80 mg/dL; 95% CI: - 14.80, - 2.81; P = 0.004), and BMI (WMD = - 0.53 kg/m2; 95% CI: - 1.05, - 0.01; P = 0.046) but not BW (WMD: - 0.51 kg, 95 % CI: - 1.99, 0.97, P = 0.498). Moreover, zinc supplementation increased HDL-C (WMD = 4.82 mg/dL; 95% CI: 0.88, 8.76; P = 0.016) in patients with T2DM. Our results propose that zinc supplementation may be an effective strategy for improving lipid profile and body composition in patients with T2DM.

Impact of very low carbohydrate ketogenic diets on cardiovascular risk factors among patients with type 2 diabetes; GRADE-assessed systematic review and meta-analysis of clinical trials

OBJECTIVE

This study was designed to evaluate the impact of VLCKD on cardiovascular risk factors in patients with T2DM.

METHODS

Until March 2024, extensive searches were conducted on PubMed, Scopus, Web of Science, Embase, and other relevant databases. The purpose was to identify clinical trials examining the impact of VLCKD on glycemic control, lipid profile, and blood pressure. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) method was used to assess the evidence's degree of certainty.

RESULTS

Our initial search found a total of 2568 records and finally 29 trials were included in final analysis. Our results showed that adherence from VLCKD led to significant reduction in fasting blood sugar (WMD= -11.68 mg/dl; 95% CI: -18.79, -4.56; P = 0.001), HbA1c (WMD= -0.29; 95% CI: -0.44, -0.14; P < 0.001), HOMA-IR(WMD= -0.71; 95% CI: -1.14, -0.29; P = 0.001), insulin (WMD= -1.45; 95% CI: -2.54, -0.36; P = 0.009), triglyceride (WMD= -17.95; 95% CI: -26.82, -9.07; P < 0.001), systolic blood pressure (WMD= -2.85, 95% CI: -4.99, -0.71; P = 0.009) and diastolic blood pressure (WMD= -1.40; 95% CI: -2.66, -0.13; P = 0.03). We also found a significant increase in high-density lipoprotein (HDL) level after adherence from VLCKD diet (WMD = 3.93, 95% CI: 2.03, 5.84; P = 0.000). We couldn't find any significant differences between groups in term of LDL and total cholesterol levels.

CONCLUSION

People following a VLCKD experience a more significant improvement in cardiovascular risk factors when compared to individuals on control diets.

Management of Type 2 Diabetes Mellitus: Synopsis of the Department of Veterans Affairs and Department of Defense Clinical Practice Guideline

The US Department of Veterans Affairs (VA) and the US Department of Defense (DoD) approved a joint clinical practice guideline for the management of type 2 diabetes. This was the product of a multidisciplinary guideline development committee composed of clinicians from both the VA and the DoD and was overseen by the VA/DoD Evidence Based Practice Work Group. The development process conformed to the standards for trustworthy guidelines as established by the National Academy of Medicine. The guideline development committee developed 12 key questions to guide an evidence synthesis. An independent third party identified relevant randomized controlled trials and systematic reviews that were published from January 2016 through April 2022. This evidence synthesis served as the basis for drafting recommendations. Twenty-six recommendations were generated and rated by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. Two algorithms were developed to guide clinical decision-making. This synopsis summarizes key aspects of the VA/DoD Clinical Practice Guideline for diabetes in 5 areas: prediabetes, screening for co-occurring conditions, diabetes self-management education and support, glycemic treatment goals, and pharmacotherapy. The guideline is designed to help clinicians and patients make informed treatment decisions to optimize health outcomes and quality of life and to align with patient-centered goals of care.

Effect of structured diet with exercise education on anthropometry and lifestyle modification in patients with type 2 diabetes: A 12-month randomized clinical trial

AIMS

Lifestyle modification involving active engagement of specialised dietitian with diet and exercise education, can be effective as first-line treatment for diabetes.

METHODS

192 patients were enrolled with diabetes in a randomised controlled trial and followed up for one year. Ninety-four patients in the intervention group participated in a comprehensive structured diet and exercise education conducted by a specialised dietitian at ambulatory centre in the United Arab Emirates.

RESULTS

The mean difference in the change in body mass index between study groups at study exit and baseline was statistically significant (BMI difference = -1.86, 95 % CI -2.68 - -1.04, P < 0.01). The intervention group reported significant decrease in total carbohydrate and daily energy intake compared to baseline (173.7 g vs 221.1 g and 1828.5 kcal vs 2177.9 kcal, respectively). Moreover, the mean metabolic equivalents (METs) in the intervention group increased significantly at study exit from baseline compared to control group METs, with mean difference between all between-group differences after baseline of 0.63 (95 % 0.29 - 0.97, P < 0.01).

CONCLUSIONS

Structured diet and exercise counselling by specialised dietitian in ambulatory settings significantly reduced carbohydrate and daily energy intake, with improved anthropometric measurements and physical activity.

The effects of major dietary patterns on patients with type 2 diabetes: Protocol for a systematic review and network meta-analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) represents a significant worldwide health issue, experiencing an increasing incidence rate. Effective dietary strategies are vital for T2DM management, but the optimal dietary patterns remain debated due to inconsistent research outcomes and single-outcome reporting. Network Meta-Analysis (NMA) provides a powerful approach for integrating data from randomized controlled trials (RCTs), enabling a detailed evaluation of the impact of different dietary patterns. This document presents our strategy for a systematic review and network meta-analysis, aimed at assessing the influence of key dietary patterns on glycemic control, lipid profiles, and weight management in individuals with Type 2 Diabetes Mellitus (T2DM).

MATERIALS AND METHODS

Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) and network meta-analyses guidelines, we conducted a comprehensive search of PubMed, EMBASE, and the Cochrane Library, without language or date restrictions. Our objective is to assess the efficacy of various dietary interventions in managing Type 2 Diabetes Mellitus (T2DM). We used standardized mean differences for pairwise comparisons and a Bayesian framework for ranking interventions via Surface Under the Cumulative Ranking Curve (SUCRA). Key analyses include heterogeneity, transitivity, and sensitivity assessments, along with quality and risk evaluations using the Cochrane Collaboration's tool and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

ETHICS AND DISSEMINATION

This systematic review and network meta-analysis involve aggregate data from previous trials, obviating the need for additional ethical approval. The search strategy will be executed starting October 2023, with all searches completed by December 2023, to encompass the most current studies available. Findings will be shared through academic conferences and peer-reviewed journals focused on diabetes care and nutrition.

TRIAL REGISTRATION

PROSPERO registration number CRD42023465791.

Association of fat-to-muscle mass ratio with physical activity and dietary protein, carbohydrate, sodium, and fiber intake in a cross-sectional study

Higher fat-to-muscle mass ratio (FMR) is reported to be a risk factor for various diseases, including type 2 diabetes and cardiovascular diseases, and mortality. Although this association suggests that reducing FMR may help to prevent certain diseases and mortality, the relationship between FMR and lifestyle factors is unclear. Therefore, we performed a cross-sectional study with the aim to elucidate this relationship. This cross-sectional study included 1518 healthy Japanese adults aged 30 to 64 years. We measured FMR in the whole body, arms, legs, and trunk and assessed various lifestyle factors. Then, we performed forced entry multiple regression analyses for FMR with the following variables: sex, age, physical activity, dietary intake, sleep quality, cigarette smoking, stress levels, and body mass index. As a result, whole-body and regional FMRs were correlated with female sex (β = 0.71); age (β = 0.06); physical activity (β = - 0.07); dietary intake of protein (β = - 0.12), carbohydrate (β = 0.04), sodium (β = 0.13), and fiber (β = - 0.16); and body mass index (β = 0.70). The results suggest that in the Japanese middle-aged population, low FMR is associated with certain lifestyle factors, i.e. higher physical activity and a diet with higher protein and fiber and lower carbohydrate and sodium, independent of age, sex, and body mass index.

Difference in association of carbohydrate intake with all-cause mortality between middle-aged and older Korean adults with and without diabetes mellitus: A prospective study

BACKGROUND & AIMS

The relationship between diet and health, particularly the role of carbohydrates, has been extensively studied. However, carbohydrate intake based on individual health conditions remains unclear. Here, we aimed to investigate whether the association between carbohydrate intake and all-cause mortality varied between individuals with and without diabetes mellitus (DM).

METHODS

This prospective cohort study used data from the Korean Genome and Epidemiology Study (KoGES). Overall, 143,050 participants were included, with 10.1% having DM. Dietary intake was assessed using a semiquantitative food frequency questionnaire. Cox proportional hazards regression models were used to assess the association between carbohydrate intake and mortality after adjusting for confounders.

RESULTS

The study showed that 5436 deaths occurred during the median follow-up period of 10.1 years. A significant interaction between carbohydrate intake and DM was observed in the study population (interaction p = 0.061). Higher carbohydrate intake proportion was associated with an increased risk of all-cause mortality among individuals with DM (adjusted hazard ratio [HR], p-value = 1.10 [1.01-1.20], p = 0.032). Conversely, no association was observed between the proportion of carbohydrate intake and all-cause mortality in participants without DM. Additionally, both total sugar and added sugar intakes were associated with an increased risk of all-cause mortality in participants with DM (adjusted HR, p-value = 1.02 [1.01-1.04], p < 0.001 and 1.18 [1.13-1.24], p < 0.001).

CONCLUSIONS

High carbohydrate (%) and added sugar intake were associated with an increased mortality risk in individuals with DM. Reducing carbohydrate intake and opting for healthy carbohydrates to mitigate mortality risk may be beneficial for individuals with DM, particularly when compared with the general population.

The association between multiple trajectories of macronutrient intake and the risk of new-onset diabetes in Chinese adults

BACKGROUND

The association between macronutrient intake and diabetes is unclear. We used data from the China Health and Nutrition Survey to explore the association between macronutrient intake trajectories and diabetes risk in this study.

METHODS

We included 6755 participants who did not have diabetes at baseline and participated in at least three surveys. The energy supply ratio of carbohydrate, protein, and fat was further calculated from dietary data; different macronutrient trajectories were determined using multitrajectory models; and multiple Cox regression models were used to evaluate the association between these trajectories and diabetes.

RESULTS

We found three multitrajectories: decreased low carbohydrate-increased moderate protein-increased high fat (DLC-IMP-IHF), decreased high carbohydrate-moderate protein-increased low fat (DHC-MP-ILF), and balanced-macronutrients (BM). Compared to the BM trajectory, DHC-MP-ILF trajectories were significantly associated with increased risk of diabetes (hazard ratio [HR]: 3.228, 95% confidence interval [CI]: 1.571-6.632), whereas no association between DLC-IMP-IHF trajectories and diabetes was found in our study (HR: 0.699, 95% CI: 0.351-1.392).

CONCLUSIONS

The downward trend of high carbohydrate and the increasing trend of low fat increased the risk of diabetes in Chinese adults.

Physical activity and arterial stiffness: is body fat a mediator?

PURPOSE

Physical activity (PA) and body fat percentage (%BF) are independently associated with arterial stiffness, but it has not been explored if there is an associative pathway among these variables. This study examined whether %BF mediates the relationship between PA or sedentary behavior levels with arterial stiffness.

METHODS

Fifty adults (1:1 men:women; age 28 ± 11 year) had carotid-femoral pulse wave velocity (CF-PWV) measured by applanation tonometry, %BF by bioelectrical impedance, and PA levels by accelerometry. Accelerometer data determined minutes per day spent in sedentary, light, moderate-to-vigorous physical activity (MVPA), and Total PA.

RESULTS

Pearson correlation indicated statistically significant associations among age, %BF, CF-PWV, MVPA, and Total PA (r = 0.34-0.65, p < 0.05). Sedentary and light PA were not associated with CF-PWV. Mediation analysis indicated significant total effects of MVPA (β = - 0.34, p = 0.044) and age (β = 0.65, p < 0.001) on CF-PWV. %BF mediated the relationship between Total PA and CF-PWV due to indirect effect of Total PA on %BF (β = - 0.34, p = 0.02) and %BF on CF-PWV (β = 0.44, p = 0.002), and partially mediated the relationship between age and CF-PWV (β = 0.54, p < 0.001). Total PA retained its significant effect on %BF (β = - 0.28, p = 0.04) and the effect of %BF on CF-PWV remained significant (β = 0.26, p = 0.03), despite age having a significant effect on both %BF (β = 0.31, p = 0.023) and CF-PWV (β = 0.54, p < 0.001).

CONCLUSIONS

%BF mediated the relationship between Total PA and arterial stiffness, even after accounting for age. Engagement in more Total PA may help to reduce %BF, resulting in decreased arterial stiffness.

Crosstalk between glucagon-like peptide 1 and gut microbiota in metabolic diseases

Gut microbiota exert influence on gastrointestinal mucosal permeability, bile acid metabolism, short-chain fatty acid synthesis, dietary fiber fermentation, and farnesoid X receptor/Takeda G protein-coupled receptor 5 (TGR5) signal transduction. The incretin glucagon-like peptide 1 (GLP-1) is mainly produced by L cells in the gut and regulates postprandial blood glucose. Changes in gut microbiota composition and function have been observed in obesity and type 2 diabetes (T2D). Meanwhile, the function and rhythm of GLP-1 have also been affected in subjects with obesity or T2D. Therefore, it is necessary to discuss the link between the gut microbiome and GLP-1. In this review, we describe the interaction between GLP-1 and the gut microbiota in metabolic diseases. On the one hand, gut microbiota metabolites stimulate GLP-1 secretion, and gut microbiota affect GLP-1 function and rhythm. On the other hand, the mechanism of action of GLP-1 on gut microbiota involves the inflammatory response. Additionally, we discuss the effects and mechanism of various interventions, such as prebiotics, probiotics, antidiabetic drugs, and bariatric surgery, on the crosstalk between gut microbiota and GLP-1. Finally, we stress that gut microbiota can be used as a target for metabolic diseases, and the clinical application of GLP-1 receptor agonists should be individualized.

A lipidomic and metabolomic signature of a very low-carbohydrate high-fat diet and high-intensity interval training: an additional analysis of a randomized controlled clinical trial

INTRODUCTION

Regular physical activity and dietary variety are modifiable and influential factors of health outcomes. However, the cumulative effects of these behaviors are not well understood. Metabolomics may have a promising research potential to extend our knowledge and use it in the attempts to find a long-term and sustainable personalized approach in exercise and diet recommendations.

OBJECTIVE

The main aim was to investigate the effect of the 12 week very low carbohydrate high fat (VLCHF) diet and high-intensity interval training (HIIT) on lipidomic and metabolomic profiles in individuals with overweight and obesity.

METHODS

The participants (N = 91) were randomly allocated to HIIT (N = 22), VLCHF (N = 25), VLCHF + HIIT (N = 25) or control (N = 19) groups for 12 weeks. Fasting plasma samples were collected before the intervention and after 4, 8 and 12 weeks. The samples were then subjected to untargeted lipidomic and metabolomic analyses using reversed phase ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry.

RESULTS

The VLCHF diet affected plasma lipids considerably while the effect of HIIT was unremarkable. Already after 4 weeks of intervention substantial changes of plasma lipids were found in both VLCHF diet groups. The changes persisted throughout the entire 12 weeks of the VLCHF diet. Specifically, acyl carnitines, plasmalogens, fatty acyl esters of hydroxy fatty acid, sphingomyelin, ceramides, cholesterol esters, fatty acids and 4-hydroxybutyric were identified as lipid families that increased in the VLCHF diet groups whereas lipid families of triglycerides and glycerophospholipids decreased. Additionally, metabolomic analysis showed a decrease of theobromine.

CONCLUSIONS

This study deciphers the specific responses to a VLCHF diet, HIIT and their combination by analysing untargeted lipidomic and metabolomic profile. VLCHF diet caused divergent changes of plasma lipids and other metabolites when compared to the exercise and control group which may contribute to a better understanding of metabolic changes and the appraisal of VLCHF diet benefits and harms.

CLINICAL TRIAL REGISTRY NUMBER

NCT03934476, registered 1st May 2019 https://clinicaltrials.gov/ct2/show/NCT03934476?term=NCT03934476&draw=2&rank=1 .

A Review of Healthy Dietary Choices for Cardiovascular Disease: From Individual Nutrients and Foods to Dietary Patterns

Cardiovascular disease (CVD) remains the first cause of mortality globally. Diet plays a fundamental role in cardiovascular health and is closely linked to the development of CVD. Numerous human studies have provided evidence on the relationship between diet and CVD. By discussing the available findings on the dietary components that potentially influence CVD progression and prevention, this review attempted to provide the current state of evidence on healthy dietary choices for CVD. We focus on the effects of individual macronutrients, whole food products, and dietary patterns on the risks of CVD, and the data from population-based trials, observational studies, and meta-analyses are summarized. Unhealthy dietary habits, such as high intake of saturated fatty acids, sugar-sweetened beverages, red meat, and processed meat as well as high salt intake are associated with the increased risk of CVD. Conversely, increased consumption of plant-based components such as dietary fiber, nuts, fruits, and vegetables is shown to be effective in reducing CVD risk factors. The Mediterranean diet appears to be one of the most evidence-based dietary patterns beneficial for CVD prevention. However, there is still great debate regarding whether the supplementation of vitamins and minerals confers cardioprotective benefits. This review provides new insights into the role of dietary factors that are harmful or protective in CVD, which can be adopted for improved cardiovascular health.

A six-month low-carbohydrate diet high in fat does not adversely affect endothelial function or markers of low-grade inflammation in patients with type 2 diabetes: an open-label randomized controlled trial

BACKGROUND

While a low-carbohydrate diet (LCD) reduces HbA1c in patients with type 2 diabetes (T2D), the associated high intake of fat may adversely affect cardiovascular risk factors. To address this, we examined the effect of a non-calorie-restricted LCD high in fat on endothelial function and markers of low-grade inflammation in T2D over 6 months.

METHODS

In an open-label randomized controlled trial, 71 patients with T2D were randomized 2:1 to either a LCD (< 20 E% carbohydrates, 50-60 E% fat) or a control diet (50-60 E% carbohydrates, 20-30 E% fat) for six months. Flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation (NID) were assessed by ultrasound in the brachial artery together with plasma interleukin-6 (IL-6) and serum high-sensitivity C-reactive protein (hsCRP) in the participants at baseline (n = 70) and after six months (n = 64).

RESULTS

The FMD and NID were unaltered in both groups after six months, and there were no between-group differences in change of either FMD (p = 0.34) or NID (p = 0.53) in response to the interventions. The circulating hsCRP and IL-6 levels decreased only in response to LCD (both p < 0.05). However, comparing changes over time with the control diet, the LCD did not reduce either IL-6 (p = 0.25) or hsCRP (p = 0.07) levels. The lack of changes in FMD and NID in response to LCD persisted after adjustment for cardiovascular risk factors.

CONCLUSION

A LCD high in fat for six months does not adversely affect endothelial function or selected markers of low-grade inflammation, which suggests that this nutritional approach does not increase the risk of cardiovascular disease. Trial registration ClinicalTrials.gov (NCT03068078).

Effect of Dietary Approaches on Glycemic Control in Patients with Type 2 Diabetes: A Systematic Review with Network Meta-Analysis of Randomized Trials

BACKGROUND

Dietary patterns play a critical role in diabetes management, while the best dietary pattern for Type 2 diabetes (T2DM) patients is still unclear. The aim of this network meta-analysis was to compare the impacts of various dietary approaches on the glycemic control of T2DM patients.

METHODS

Relevant studies were retrieved from PubMed, Embase, Web of Knowledge, Cochrane Central Register of Controlled Trials (CENTRAL), and other additional records (1949 to 31 July 2022). Eligible RCTs were those comparing different dietary approaches against each other or a control diet in individuals with T2DM for at least 6 months. We assessed the risk of bias of included studies with the Cochrane risk of bias tool and confidence of estimates with the Grading of Recommendations Assessment, Development, and Evaluation approach for network meta-analyses. In order to determine the pooled effect of each dietary approach relative to each other, we performed a network meta-analysis (NMA) for interventions for both HbA1c and fasting glucose, which enabled us to estimate the relative intervention effects by combing both direct and indirect trial evidence.

RESULTS

Forty-two RCTs comprising 4809 patients with T2DM were included in the NMA, comparing 10 dietary approaches (low-carbohydrate, moderate-carbohydrate, ketogenic, low-fat, high-protein, Mediterranean, Vegetarian/Vegan, low glycemic index, recommended, and control diets). In total, 83.3% of the studies were at a lower risk of bias or had some concerns. Findings of the NMA revealed that the ketogenic, low-carbohydrate, and low-fat diets were significantly effective in reducing HbA1c (viz., -0.73 (-1.19, -0.28), -0.69 (-1.32, -0.06), and -1.82 (-2.93, -0.71)), while moderate-carbohydrate, low glycemic index, Mediterranean, high-protein, and low-fat diets were significantly effective in reducing fasting glucose (viz., -1.30 (-1.92, -0.67), -1.26 (-2.26, -0.27), -0.95 (-1.51, -0.38), -0.89 (-1.60, -0.18) and -0.75 (-1.24, -0.27)) compared to a control diet. The clustered ranking plot for combined outcomes indicated the ketogenic, Mediterranean, moderate-carbohydrate, and low glycemic index diets had promising effects for controlling HbA1c and fasting glucose. The univariate meta-regressions showed that the mean reductions of HbA1c and fasting glucose were only significantly related to the mean weight change of the subjects.

CONCLUSIONS

For glycemic control in T2DM patients, the ketogenic diet, Mediterranean diet, moderate-carbohydrate diet, and low glycemic index diet were effective options. Although this study found the ketogenic diet superior, further high-quality and long-term studies are needed to strengthen its credibility.

Diet, exercise, and pharmacotherapy for sarcopenia in people with diabetes

Diabetes prevalence is increasing rapidly in older people, and sarcopenia is prevalent as a novel complication, particularly in patients with type 2 diabetes mellitus (T2DM). Therefore, sarcopenia prevention and treatment in these people is necessary. Diabetes accelerates sarcopenia through several mechanisms, such as hyperglycemia, chronic inflammation and oxidative stress. The effects of diet, exercise, and pharmacotherapy on sarcopenia in patients with T2DM need to be considered. In diet, low intake of energy, protein, vitamin D, and ω-3 fatty acid are associated with sarcopenia risk. In exercises, although intervention studies in people, especially older and non-obese patients with diabetes, are few, accumulating evidence shows the usefulness of exercise, particularly resistance exercise for muscle mass and strength, and aerobic exercise for physical performance in sarcopenia. In pharmacotherapy, certain classes of anti-diabetes compounds have possibility of preventing sarcopenia. However, much data on diet, exercise, and pharmacotherapy were obtained in obese and non-elderly patients with T2DM, demanding actual clinical data on non-obese and older patients with diabetes.

Effect of Calorie-Unrestricted Low-Carbohydrate, High-Fat Diet Versus High-Carbohydrate, Low-Fat Diet on Type 2 Diabetes and Nonalcoholic Fatty Liver Disease : A Randomized Controlled Trial

BACKGROUND

It remains unclear if a low-carbohydrate, high-fat (LCHF) diet is a possible treatment strategy for type 2 diabetes mellitus (T2DM), and the effect on nonalcoholic fatty liver disease (NAFLD) has not been investigated.

OBJECTIVE

To investigate the effect of a calorie-unrestricted LCHF diet, with no intention of weight loss, on T2DM and NAFLD compared with a high-carbohydrate, low-fat (HCLF) diet.

DESIGN

6-month randomized controlled trial with a 3-month follow-up. (ClinicalTrials.gov: NCT03068078).

SETTING

Odense University Hospital in Denmark from November 2016 until June 2020.

PARTICIPANTS

165 participants with T2DM.

INTERVENTION

Two calorie-unrestricted diets: LCHF diet with 50 to 60 energy percent (E%) fat, less than 20E% carbohydrates, and 25E% to 30E% proteins and HCLF diet with 50E% to 60E% carbohydrates, 20E% to 30E% fats, and 20E% to 25E% proteins.

MEASUREMENTS

Glycemic control, serum lipid levels, metabolic markers, and liver biopsies to assess NAFLD.

RESULTS

The mean age was 56 years (SD, 10), and 58% were women. Compared with the HCLF diet, participants on the LCHF diet had greater improvements in hemoglobin A_1c (mean difference in change, -6.1 mmol/mol [95% CI, -9.2 to -3.0 mmol/mol] or -0.59% [CI, -0.87% to -0.30%]) and lost more weight (mean difference in change, -3.8 kg [CI, -6.2 to -1.4 kg]). Both groups had higher high-density lipoprotein cholesterol and lower triglycerides at 6 months. Changes in low-density lipoprotein cholesterol were less favorable in the LCHF diet group than in the HCLF diet group (mean difference in change, 0.37 mmol/L [CI, 0.17 to 0.58 mmol/L] or 14.3 mg/dL [CI, 6.6 to 22.4 mg/dL]). No statistically significant between-group changes were detected in the assessment of NAFLD. Changes were not sustained at the 9-month follow-up.

LIMITATION

Open-label trial, self-reported adherence, unintended weight loss, and lack of adjustment for multiple comparisons.

CONCLUSION

Persons with T2DM on a 6-month, calorie-unrestricted, LCHF diet had greater clinically meaningful improvements in glycemic control and weight compared with those on an HCLF diet, but the changes were not sustained 3 months after intervention.

PRIMARY FUNDING SOURCE

Novo Nordisk Foundation.

Comparative efficacy of different eating patterns in the management of type 2 diabetes and prediabetes: An arm-based Bayesian network meta-analysis

AIMS/INTRODUCTION

Diet therapy is a vital approach to manage type 2 diabetes and prediabetes. However, the comparative efficacy of different eating patterns is not clear enough. We aimed to compare the efficacy of various eating patterns for glycemic control, anthropometrics, and serum lipid profiles in the management of type 2 diabetes and prediabetes.

MATERIALS AND METHODS

We conducted a network meta-analysis using arm-based Bayesian methods and random effect models, and drew the conclusions using the partially contextualized framework. We searched twelve databases and yielded 9,534 related references, where 107 studies were eligible, comprising 8,909 participants.

RESULTS

Eleven diets were evaluated for 14 outcomes. Caloric restriction was ranked as the best pattern for weight loss (SUCRA 86.8%) and waist circumference (82.2%), low-carbohydrate diets for body mass index (81.6%), and high-density lipoprotein (84.0%), and low-glycemic-index diets for total cholesterol (87.5%) and low-density lipoprotein (86.6%). Other interventions showed some superiorities, but were imprecise due to insufficient participants and needed further investigation. The attrition rates of interventions were similar. Meta-regression suggested that macronutrients, energy intake, and weight may modify outcomes differently. The evidence was of moderate-to-low quality, and 38.2% of the evidence items met the minimal clinically important differences.

CONCLUSIONS

The selection and development of dietary strategies for diabetic/prediabetic patients should depend on their holistic conditions, i.e., serum lipid profiles, glucometabolic patterns, weight, and blood pressure. It is recommended to identify the most critical and urgent metabolic indicator to control for one specific patient, and then choose the most appropriate eating pattern accordingly.

Very low carbohydrate (ketogenic) diets in type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

AIM

Very low carbohydrate/ketogenic diets (VLC/KDs) are popular but their role in managing pre-diabetes and type 2 diabetes (T2D) is uncertain. This study uses a systematic review and meta-analysis of randomized controlled trials to estimate the effect of these diets in this population.

MATERIALS AND METHODS

A systematic review identified randomized controlled trials of at least 6 months duration comparing efficacy and safety of VLC/KDs (≤50 g carbohydrate or ≤10% total energy from carbohydrate per day) with a control diet (carbohydrate above the VLC/KD threshold) in adults with pre-diabetes or T2D. The primary outcome variable was glycated haemoglobin (HbA1c) after 12 months. The meta-analysis method was inverse variance weighting of mean values for continuous variables.

RESULTS

Key word searches identified 2290 studies; 2221 were not in scope. A full text review of 69 studies identified eight meeting inclusion criteria; in total, it involved 606 participants. Six studies reported HbA1c (%) at 12 months; four as change from baseline with a fixed effects estimate (95% confidence interval): VLC/KD minus control of 0.01% (-0.22 to 0.25), p = .91; and two as change from baseline: -0.65% (-0.99; -0.31) [-7.1 mmol/mol (-10.8; -3.4)], p < .001. Serum triglycerides were lower with VLC/KD versus control: -0.28 mmol/L (-0.44 to -0.11), p < .001. High-density lipoprotein was higher with an estimate of 0.04 mmol/L (0.01 to 0.08), p = .03, in the five studies reporting 12-month summary data.

CONCLUSIONS

A VLC/KD may cause reductions in HbA1c and triglycerides in those with pre-diabetes or T2D but evidence of an advantage over other strategies is limited. More well-designed studies are required to provide certain evidence.

Statin therapy is not warranted for a person with high LDL-cholesterol on a low-carbohydrate diet

PURPOSE OF REVIEW

Although there is an extensive literature on the efficacy of the low carbohydrate diet (LCD) for weight loss and in the management of type 2 diabetes, concerns have been raised that the LCD may increase cardiovascular disease (CVD) risk by increasing the level of low-density lipoprotein cholesterol (LDL-C). We have assessed the value of LDL-C as a CVD risk factor, as well as effects of the LCD on other CVD risk factors. We have also reviewed findings that provide guidance as to whether statin therapy would be beneficial for individuals with high LDL-C on an LCD.

RECENT FINDINGS

Multiple longitudinal trials have demonstrated the safety and effectiveness of the LCD, while also providing evidence of improvements in the most reliable CVD risk factors. Recent findings have also confirmed how ineffective LDL-C is in predicting CVD risk.

SUMMARY

Extensive research has demonstrated the efficacy of the LCD to improve the most robust CVD risk factors, such as hyperglycemia, hypertension, and atherogenic dyslipidemia. Our review of the literature indicates that statin therapy for both primary and secondary prevention of CVD is not warranted for individuals on an LCD with elevated LDL-C who have achieved a low triglyceride/HDL ratio.

Choices of (in)action in obesity: Implications for research on treatment and prevention

The obesity epidemic has crossed social-demographic barriers and is a matter of significant concern. Why do individuals fail to restrain from eating high-calorie foods and fail to follow treatment routines that reduce the risk of health complications? These questions have been addressed through behavioral and brain imaging studies on prefrontal cortex inhibitory mechanisms. Failure to inhibit undesirable behaviors has become a hallmark of obesity. In many life situations, obesity risk is increased by inaction (e.g., not taking blood pressure medication, not following a healthy diet). Risk by inaction has been defined as passive risk-taking, and it is correlated with traits such as procrastination, future time perspective, and cognitive avoidance. To the present, passive tendencies, specifically in the context of risk-taking behaviors, have not been addressed in the obesity literature. We introduce a framework in which active and passive risk-taking behaviors are integrated within the scope of bidirectional models of obesity that describe the brain as both the cause and the consequence of obesity vulnerability. The present perspective aims to foster new research on treatment and prevention, and also on the neurobiology of passive behaviors in obesity and other metabolic conditions.

Imidazole Propionate is Increased in Diabetes and Associated with Stool Consistency

BACKGROUND

Imidazole Propionate (ImP) is a new marker of Type 2 diabetes mellitus (T2DM), which can induce impaired glucose metabolism and weaken the efficacy of metformin. An extensive exploration into literature suggests that ImP may be associated with stool consistency.

PURPOSE

Through an in-depth study of the relationship between stool consistency, bile acids, fecal microbiota and ImP, we intend to explore the mechanism driving the ImP content difference in T2DM.

PATIENTS UNDER STUDY AND METHODS

This is a single-center, prospective, cross-sectional study. Plasma ImP and stool consistency were analyzed among 96 diabetic subjects and 45 healthy subjects. All subjects were divided into the stool consistency normal (N) group and the stool consistency abnormal group, of which the abnormal group was sub-divided into the hard stool (H) group and the soft stool (S) group. After identifying the correlation between ImP and stool consistency, we analyzed the influence of bile acids and fecal microbiota on ImP in diabetic subjects.

RESULTS

For T2DM patients, the ImP level of the abnormal stool consistency group was significantly higher than that of the normal stool consistency group (P < 0.001). Results were verified in 45 healthy subjects (P = 0.002). ImP was significantly associated with taurocholic acid (TCA) (P = 0.003) in feces, taurodeoxycholate (TDCA) (P = 0.003), glycochenodeoxycholate (GCDCA) (P = 0.021), and glycocholic acid (GCA) (P = 0.031) in plasma. The Shannon index of Group N was significantly higher than that of Group H (P = 0.041) and Group S (P = 0.003).

CONCLUSION

ImP was higher in diabetic patients with abnormal stool consistency than in those with normal stool consistency, which was related to the proportion of bile acids and fecal microbial structure. These findings may improve our understanding of ImP and contribute to the treatment of T2DM by improving stool consistency.