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

Ketogenic Diet and Its Potential Role in Preventing Type 2 Diabetes Mellitus and Its Complications: A Narrative Review of Randomized Controlled Trials

Diabetes mellitus is a global health crisis affecting millions. Nutrition plays a vital role in its management and prevention. While carbohydrate reduction is beneficial for glycemic control, various dietary approaches exist. The ketogenic diet, characterized by very low carbohydrate intake, has shown promise in weight management and blood sugar control. However, its potential for preventing type 2 diabetes mellitus (T2DM) remains largely unexplored. To evaluate the ketogenic diet's potential in preventing T2DM, this review searched the PubMed database for studies published between 2013 and 2023. Findings suggest that the diet can effectively aid weight loss and improve blood glucose levels. Some evidence indicates reduced reliance on diabetes medications. However, effects on cholesterol levels are inconsistent, and long-term adherence challenges exist. Additionally, potential micronutrient deficiencies and safety concerns require careful consideration. While the ketogenic diet offers potential benefits, further research is needed to establish its efficacy and safety as a long-term prevention strategy for T2DM. However, the results of the present study indicate the need for further research in this area, utilizing rigorous methodology.

Impact of the ketogenic diet as a dietary approach on cardiovascular disease risk factors: a meta-analysis of randomized clinical trials

BACKGROUND

Cardiovascular diseases (CVD) remain the leading cause of mortality globally, and the scarcity of scientific evidence regarding the impact of ketogenic diets on CVD risk factors necessitates urgent attention and redress.

OBJECTIVES

This meta-analysis evaluates the impact of the ketogenic diet on CVD risk factors compared with control diets through randomized controlled trials (RCTs).

METHODS

The study was registered in advance in the PROSPERO database (CRD42023491853). A systematic search was conducted across PubMed, Web of Science, EMBASE, and Cochrane Library to identify relevant RCTs. Fixed and random effects were employed to calculate the mean differences and 95% confidence intervals (CIs) for changes in CVD risk factors pre- and postketogenic diet intervention.

RESULTS

A total of 27 RCTs with 1278 participants were analyzed. The ketogenic diet intervention presented increase in total cholesterol (mean differences: 0.36 mmol/L; 95% CI: 0.15, 0.57; I2: 85.1%), low-density lipoprotein cholesterol (mean differences: 0.35 mmol/L; 95% CI: 0.20, 0.50; I2: 73.9%) and high-density lipoprotein cholesterol (mean differences: 0.16 mmol/L; 95% CI: 0.09, 0.23; I2: 86.7%) concentrations. Reductions were observed in the triglyceride (mean differences: -0.20 mmol/L; 95% CI: -0.29, -0.11; I2: 72.2%), blood glucose (mean differences: -0.18 mmol/L; 95% CI: -0.33, -0.02; I2: 76.4%), blood insulin (mean differences: -8.32 pmol/L; 95% CI: -14.52, -2.12; I2: 81.5%), diastolic blood pressure (mean differences: -1.41 mmHg; 95% CI: -2.57, -0.26; I2: 49.1%), weight (mean differences: -2.59 kg; 95% CI: -3.90, -1.28; I2: 87.4%), and body mass index (mean differences: -1.59 kg/m2; 95% CI: -2.32, -0.86; I2: 84.5%) concentrations after implementing ketogenic diets.

CONCLUSIONS

Although the ketogenic diet demonstrates benefits in terms of triglyceride, blood pressure, weight, and glycemic control, its impact on CVD risk factors, especially the elevated total cholesterol and low-density lipoprotein cholesterol concentrations, warrants a cautious approach.

Impacts of dietary animal and plant protein on weight and glycemic control in health, obesity and type 2 diabetes: friend or foe?

It is well established that high-protein diets (i.e. ~25-30% of energy intake from protein) provide benefits for achieving weight loss, and subsequent weight maintenance, in individuals with obesity, and improve glycemic control in type 2 diabetes (T2D). These effects may be attributable to the superior satiating property of protein, at least in part, through stimulation of both gastrointestinal (GI) mechanisms by protein, involving GI hormone release and slowing of gastric emptying, as well as post-absorptive mechanisms facilitated by circulating amino acids. In contrast, there is evidence that the beneficial effects of greater protein intake on body weight and glycemia may only be sustained for 6-12 months. While both suboptimal dietary compliance and metabolic adaptation, as well as substantial limitations in the design of longer-term studies are all likely to contribute to this contradiction, the source of dietary protein (i.e. animal vs. plant) has received inappropriately little attention. This issue has been highlighted by outcomes of recent epidemiological studies indicating that long-term consumption of animal-based protein may have adverse effects in relation to the development of obesity and T2D, while plant-based protein showed either protective or neutral effects. This review examines information relating to the effects of dietary protein on appetite, energy intake and postprandial glycemia, and the relevant GI functions, as reported in acute, intermediate- and long-term studies in humans. We also evaluate knowledge relating to the relevance of the dietary protein source, specifically animal or plant, to the prevention, and management, of obesity and T2D.

Association between Dietary Pattern, Weight Loss, and Diabetes among Adults with a History of Bariatric Surgery: Results from the Qatar Biobank Study

We aimed to examine the association between weight loss, dietary patterns, diabetes, and glycemic control among Qatari adults with a history of bariatric surgery (BS). Data from 1893 adults from the Qatar Biobank study were analyzed. Diabetes was defined by blood glucose, HbA1c, and medical history, with poor glycemic control defined as HbA1c ≥ 7.0%. The dietary patterns were derived from a Food Frequency Questionnaire using factor analysis. The participants' mean age was 38.8 years, with a mean weight loss of 23.4% and a 6.1% prevalence of poor glycemic control. Weight loss was inversely associated with diabetes and poor glycemic control. The traditional dietary pattern (high intake of Biryani, chicken, meat, fish dishes, zaatar fatayer, croissant, lasagna, and Arabic bread) was inversely associated with diabetes prevalence, with an OR of 0.61 (95%CI, 0.41-0.99) when comparing extreme quartiles. No significant associations were found between prudent or sweet dietary patterns and diabetes. Among the individuals with known diabetes, the prevalence of remission was 33.4%, with an OR for remission of 5.94 (95%CI, 1.89-18.69) for the extreme quartiles of weight loss. In conclusion, weight loss and traditional dietary patterns are inversely associated with diabetes and glycemic control among adults with a history of BS, with weight loss being the main determinant.

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.

Eight Weeks of Intermittent Exercise in Hypoxia, with or without a Low-Carbohydrate Diet, Improves Bone Mass and Functional and Physiological Capacity in Older Adults with Type 2 Diabetes

In an increasingly aging and overweight population, osteoporosis and type 2 diabetes (T2DM) are major public health concerns. T2DM patients experience prejudicial effects on their bone health, affecting their physical capacity. Exercise in hypoxia (EH) and a low-carbohydrate diet (LCD) have been suggested for therapeutic benefits in T2DM, improving bone mineral content (BMC) and glycemic control. This study investigated the effects of EH combined with an LCD on body composition and functional and physiologic capacity in T2DM patients. Older T2DM patients (n = 42) were randomly assigned to the following groups: (1) control group: control diet + exercise in normoxia; (2) EH group: control diet + EH; (3) intervention group: LCD + EH. Cardiopulmonary tests (BRUCE protocol), body composition (DEXA), and functional capacity (6MWT, handgrip strength) were evaluated. Body mass index (kg/m2) and body fat (%) decreased in all groups (p < 0.001). BMC (kg) increased in all groups (p < 0.001) and was significantly higher in the EH and EH + LCD groups (p < 0.001). VO2peak improved in all groups (p < 0.001), but more so in the hypoxia groups (p = 0.019). Functional capacity was increased in all groups (p < 0.001), but more so in the EH group in 6MWT (p = 0.030). EH with and without an LCD is a therapeutic strategy for improving bone mass in T2DM, which is associated with cardiorespiratory and functional improvements.

Low-carbohydrate dietary score and the incidence of metabolically unhealthy phenotype based on BMI status: a cohort study

There is scarce research focusing on the relationship between the low-carbohydrate dietary score and the development of a metabolically unhealthy phenotype. Therefore, this cohort study was designed to assess the association between the low-carbohydrate dietary score and the risk of metabolically unhealthy phenotypes (MUP). This study included 1299 adults with healthy metabolic profiles who were followed for 5.9 years. Results indicated an inverse association between the second tertile of the low-carbohydrate dietary score and the risk of developing metabolically unhealthy obesity (MUO) (HR: 0.76, 95% CI: 0.59-0.98). In addition, we found an inverse association between the healthy low-carbohydrate dietary score and the risk of MUO (HR: 0.77, 95% CI: 0.60-0.99). Our results revealed a nonlinear inverse association between the low-carbohydrate dietary score and the risk of MUP only in subjects with overweight or obesity. This relationship was independent of animal protein and fat intake. Also, we found that a lower intake of unhealthy carbohydrates was associated with a lower risk of MUP only in subjects with overweight or obesity.

Edible traditional Chinese medicines improve type 2 diabetes by modulating gut microbiotal metabolites

Type 2 diabetes mellitus (T2DM) is a metabolic disorder with intricate pathogenic mechanisms. Despite the availability of various oral medications for controlling the condition, reports of poor glycemic control in type 2 diabetes persist, possibly involving unknown pathogenic mechanisms. In recent years, the gut microbiota have emerged as a highly promising target for T2DM treatment, with the metabolites produced by gut microbiota serving as crucial intermediaries connecting gut microbiota and strongly related to T2DM. Increasingly, traditional Chinese medicine is being considered to target the gut microbiota for T2DM treatment, and many of them are edible. In studies conducted on animal models, edible traditional Chinese medicine have been shown to primarily alter three significant gut microbiotal metabolites: short-chain fatty acids, bile acids, and branched-chain amino acids. These metabolites play crucial roles in alleviating T2DM by improving glucose metabolism and reducing inflammation. This review primarily summarizes twelve edible traditional Chinese medicines that improve T2DM by modulating the aforementioned three gut microbiotal metabolites, along with potential underlying molecular mechanisms, and also incorporation of edible traditional Chinese medicines into the diets of T2DM patients and combined use with probiotics for treating T2DM are discussed.

Ketogenic diet and cardiovascular risk - state of the art review

The ketogenic diet is based on extreme carbohydrate intake reduction and replacing the remaining with fat and has become a popular dietary pattern used for weight loss. The relationship between the ketogenic diet and cardiovascular risk is a controversial topic. This publication aimed to present evidence on the ketogenic diet and cardiovascular risk factors and mortality. The ketogenic diet does not fulfill the criteria of a healthy diet. It presents the potential for rapid short-term reduction of body mass, triglycerides level, Hb1Ac, and blood pressure. Its efficacy for weight loss and the above-mentioned metabolic changes is not significant in long-term observations. In terms of cardiovascular mortality, the low-carb pattern is more beneficial than very low-carbohydrate (including the ketogenic diet). There is still scarce evidence comparing ketogenic to the Mediterranean diet. Other safety concerns in cardiovascular patients such as adverse events related to ketosis, fat-free mass loss, or potential pharmacological interactions should be also taken into consideration in future research.

Nutritional Aspects to Cardiovascular Diseases and Type 2 Diabetes Mellitus

PURPOSE OF REVIEW

In this narrative review, we discuss the current evidence related to the role of dietary interventions to prevent and treat type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). We also propose alternative therapeutic strategies other than weight loss in this population, namely, improvements in cardiorespiratory fitness and its determinants.

RECENT FINDINGS

While weight loss has been consistently associated with the prevention of T2DM and improvements in glycemic control in those with established diseases, its role in preventing and treating CVD is less clear. In fact, in this setting, improvements in diet quality have provided greater benefits, suggesting that this might represent an alternative, or an even more effective strategy than energy-restriction. Improvements in diet quality, with and without caloric restriction have been shown to improve CVD risk and to prevent the development of T2DM in individuals at risk; however, with regard to glycemic control in patients with T2DM, any dietary intervention resulting in significant weight loss may produce clinically meaningful benefits. Finally, dietary interventions with and without energy restriction that can improve cardiorespiratory fitness, even in absence of weight loss in patients with obesity, should be encouraged.

Comparative Evaluation of a Low-Carbohydrate Diet and a Mediterranean Diet in Overweight/Obese Patients with Type 2 Diabetes Mellitus: A 16-Week Intervention Study

INTRODUCTION

The worldwide prevalence of type 2 diabetes mellitus (T2DM) and obesity has been steadily increasing over the past four decades, with projections indicating a significant rise in the number of affected individuals by 2045. Therapeutic interventions in T2DM aim to control blood glucose levels and reduce the risk of complications. Dietary and lifestyle modifications play a crucial role in the management of T2DM and obesity. While conventional medical nutritional therapy (MNT) often promotes a high-carbohydrate, low-fat Mediterranean diet as an elective treatment, low-carbohydrate diets (LCDs), specifically those restricting carbohydrate intake to less than 130 g/day, have gained popularity due to their multifaceted benefits. Scientific research supports the efficacy of LCDs in improving glycemic control, weight loss, blood pressure, lipid profiles, and overall quality of life. However, sustaining these benefits over the long term remains challenging. This trial aimed to compare the effects of a Mediterranean diet vs. a low-carbohydrate diet (carbohydrate intake < 130 g/day) on overweight/obese patients with T2DM over a 16-week period. The study will evaluate the differential effects of these diets on glycemic regulation, weight reduction, lipid profile, and cardiovascular risk factors.

METHODS

The study population comprises 100 overweight/obese patients with poorly controlled T2DM. Anthropometric measurements, bioimpedance analysis, and blood chemistry assessments will be conducted at baseline and after the 16-week intervention period. Both dietary interventions were hypocaloric, with a focus on maintaining a 500 kcal/day energy deficit.

RESULTS

After 16 weeks, both diets had positive effects on various parameters, including weight loss, blood pressure, glucose control, lipid profile, and renal function. However, the low-carbohydrate diet appears to result in a greater reduction in BMI, blood pressure, waist circumference, glucose levels, lipid profiles, cardiovascular risk, renal markers, and overall metabolic parameters compared to the Mediterranean diet at the 16-week follow up.

CONCLUSIONS

These findings suggest that a low-carbohydrate diet may be more effective than a Mediterranean diet in promoting weight loss and improving various metabolic and cardiovascular risk factors in overweight/obese patients with T2DM. However, it is important to note that further research is needed to understand the clinical implications and long-term sustainability of these findings.

Advances in Research on Type 2 Diabetes Mellitus Targets and Therapeutic Agents

Diabetes mellitus is a chronic multifaceted disease with multiple potential complications, the treatment of which can only delay and prolong the terminal stage of the disease, i.e., type 2 diabetes mellitus (T2DM). The World Health Organization predicts that diabetes will be the seventh leading cause of death by 2030. Although many antidiabetic medicines have been successfully developed in recent years, such as GLP-1 receptor agonists and SGLT-2 inhibitors, single-target drugs are gradually failing to meet the therapeutic requirements owing to the individual variability, diversity of pathogenesis, and organismal resistance. Therefore, there remains a need to investigate the pathogenesis of T2DM in more depth, identify multiple therapeutic targets, and provide improved glycemic control solutions. This review presents an overview of the mechanisms of action and the development of the latest therapeutic agents targeting T2DM in recent years. It also discusses emerging target-based therapies and new potential therapeutic targets that have emerged within the last three years. The aim of our review is to provide a theoretical basis for further advancement in targeted therapies for T2DM.