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The American Journal of Clinical... Sep 2022Consensus has not been reached on what constitutes an optimal diet in individuals with prediabetes and type 2 diabetes mellitus (T2DM), especially between... (Randomized Controlled Trial)
Randomized Controlled Trial
Effect of a ketogenic diet versus Mediterranean diet on glycated hemoglobin in individuals with prediabetes and type 2 diabetes mellitus: The interventional Keto-Med randomized crossover trial.
BACKGROUND
Consensus has not been reached on what constitutes an optimal diet in individuals with prediabetes and type 2 diabetes mellitus (T2DM), especially between low-carbohydrate options.
OBJECTIVES
We compared 2 low-carbohydrate diets with 3 key similarities (incorporating nonstarchy vegetables and avoiding added sugars and refined grains) and 3 key differences (incorporating compared with avoiding legumes, fruits, and whole, intact grains) for their effects on glucose control and cardiometabolic risk factors in individuals with prediabetes and T2DM.
METHODS
Keto-Med was a randomized, crossover, interventional trial. Forty participants aged ≥18 years with prediabetes or T2DM followed the well-formulated ketogenic diet (WFKD) and the Mediterranean-plus diet (Med-Plus) for 12 weeks each, in random order. The diets shared the 3 key similarities noted above. The Med-Plus incorporated legumes, fruits, and whole, intact grains, while the WFKD avoided them. The primary outcome was the percentage change in glycated hemoglobin (HbA1c) after 12 weeks on each diet. Secondary and exploratory outcomes included percentage changes in body weight, fasting insulin, glucose, and blood lipids; average glucose from continuous glucose monitor (CGM), and nutrient intake.
RESULTS
The primary analysis was of 33 participants with complete data. The HbA1c values did not differ between diets at 12 weeks. Triglycerides decreased more for the WFKD [percentage changes, -16% (SEM, 4%) compared with -5% (SEM, 6%) for the Med-Plus; P = 0.02] and LDL cholesterol was higher for the WFKD [percentage changes, +10% (SEM, 4%) compared with -5% (SEM, 5%) for the Med-Plus; P = 0.01]. Weight decreased 8% (SEM, 1%) compared with 7% (SEM, 1%) and HDL cholesterol increased 11% (SEM, 2%) compared with 7% (SEM, 3%) for the WFKD compared with the Med-Plus, respectively; however, there was a significant interaction of diet × order for both. Participants had lower intakes of fiber and 3 nutrients on the WFKD compared with the Med-Plus. Twelve-week follow-up data suggest the Med-Plus is more sustainable.
CONCLUSIONS
HbA1c values were not different between diet phases after 12 weeks, but improved from baseline on both diets, likely due to several shared dietary aspects. The WFKD led to a greater decrease in triglycerides, but also had potential untoward risks from elevated LDL cholesterol and lower nutrient intakes from avoiding legumes, fruits, and whole, intact grains, as well as being less sustainable. This trial was registered at clinicaltrials.gov as NCT03810378.
Topics: Adolescent; Adult; Blood Glucose; Cholesterol, LDL; Cross-Over Studies; Diabetes Mellitus, Type 2; Diet, Ketogenic; Diet, Mediterranean; Glycated Hemoglobin; Humans; Prediabetic State; Triglycerides; Vegetables
PubMed: 35641199
DOI: 10.1093/ajcn/nqac154 -
BMJ (Clinical Research Ed.) Apr 2020To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement... (Meta-Analysis)
Meta-Analysis
Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials.
OBJECTIVE
To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement among adults who are overweight or obese.
DESIGN
Systematic review and network meta-analysis of randomised trials.
DATA SOURCES
Medline, Embase, CINAHL, AMED, and CENTRAL from database inception until September 2018, reference lists of eligible trials, and related reviews.
STUDY SELECTION
Randomised trials that enrolled adults (≥18 years) who were overweight (body mass index 25-29) or obese (≥30) to a popular named diet or an alternative diet.
OUTCOMES AND MEASURES
Change in body weight, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, systolic blood pressure, diastolic blood pressure, and C reactive protein at the six and 12 month follow-up.
REVIEW METHODS
Two reviewers independently extracted data on study participants, interventions, and outcomes and assessed risk of bias, and the certainty of evidence using the GRADE (grading of recommendations, assessment, development, and evaluation) approach. A bayesian framework informed a series of random effects network meta-analyses to estimate the relative effectiveness of the diets.
RESULTS
121 eligible trials with 21 942 patients were included and reported on 14 named diets and three control diets. Compared with usual diet, low carbohydrate and low fat diets had a similar effect at six months on weight loss (4.63 4.37 kg, both moderate certainty) and reduction in systolic blood pressure (5.14 mm Hg, moderate certainty 5.05 mm Hg, low certainty) and diastolic blood pressure (3.21 2.85 mm Hg, both low certainty). Moderate macronutrient diets resulted in slightly less weight loss and blood pressure reductions. Low carbohydrate diets had less effect than low fat diets and moderate macronutrient diets on reduction in LDL cholesterol (1.01 mg/dL, low certainty 7.08 mg/dL, moderate certainty 5.22 mg/dL, moderate certainty, respectively) but an increase in HDL cholesterol (2.31 mg/dL, low certainty), whereas low fat (-1.88 mg/dL, moderate certainty) and moderate macronutrient (-0.89 mg/dL, moderate certainty) did not. Among popular named diets, those with the largest effect on weight reduction and blood pressure in comparison with usual diet were Atkins (weight 5.5 kg, systolic blood pressure 5.1 mm Hg, diastolic blood pressure 3.3 mm Hg), DASH (3.6 kg, 4.7 mm Hg, 2.9 mm Hg, respectively), and Zone (4.1 kg, 3.5 mm Hg, 2.3 mm Hg, respectively) at six months (all moderate certainty). No diets significantly improved levels of HDL cholesterol or C reactive protein at six months. Overall, weight loss diminished at 12 months among all macronutrient patterns and popular named diets, while the benefits for cardiovascular risk factors of all interventions, except the Mediterranean diet, essentially disappeared.
CONCLUSIONS
Moderate certainty evidence shows that most macronutrient diets, over six months, result in modest weight loss and substantial improvements in cardiovascular risk factors, particularly blood pressure. At 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42015027929.
Topics: Blood Pressure; Body Mass Index; Body Weight; Cardiovascular Diseases; Cholesterol, HDL; Cholesterol, LDL; Diet, Carbohydrate-Restricted; Diet, Fat-Restricted; Diet, Mediterranean; Humans; Network Meta-Analysis; Nutrients; Obesity; Randomized Controlled Trials as Topic; Risk Reduction Behavior; Weight Loss
PubMed: 32238384
DOI: 10.1136/bmj.m696 -
Endocrine Practice : Official Journal... Dec 2020Cholesterol is an important molecule in humans and both its excess and its deficiency cause disease. Most clinicians appreciate its role in stabilizing cellular plasma... (Review)
Review
OBJECTIVE
Cholesterol is an important molecule in humans and both its excess and its deficiency cause disease. Most clinicians appreciate its role in stabilizing cellular plasma membranes but are unaware of its myriad other functions.
METHODS
This review highlights cholesterol's newly recognized important roles in human physiology and pathophysiology.
RESULTS
The basis for cholesterol's ubiquitous presence in eukaryote organisms is its three part structure involving hydrophilic, hydrophobic, and rigid domains. This structure permits cholesterol to regulate multiple cellular processes ranging from membrane fluidity and permeability to gene transcription. Cholesterol not only serves as a molecule of regulation itself, but also forms the backbone of all steroid hormones and vitamin D analogs. Cholesterol is responsible for growth and development throughout life and may be useful as an anticancer facilitator. Because humans have a limited ability to catabolize cholesterol, it readily accumulates in the body when an excess from the diet or a genetic abnormality occurs. This accumulation results in the foremost cause of death and disease (atherosclerosis) in the Western world. Identification of cholesterol's disease-producing capabilities dates back 5,000 years to the Tyrolean iceman and more recently to ancient mummies from many cultures throughout the world. In contrast, a deficiency of cholesterol in the circulation may result in an inability to distribute vitamins K and E to vital organs with serious consequences.
CONCLUSION
Understanding the benefits and hazards of cholesterol in the clinical setting will improve the endocrinologist's ability to control diseases associated with this unique molecule.
ABBREVIATIONS
CVD = cardiovascular disease; HDL = high-density lipoprotein; LDL = low-density lipoprotein; NPC1L1 = Niemann-Pick C-1-like-1 protein; U.S. = United States; USDA = U.S. Department of Agriculture.
Topics: Atherosclerosis; Cholesterol; Cholesterol, HDL; Diet; Humans
PubMed: 33471744
DOI: 10.4158/EP-2020-0347 -
Nutrition, Metabolism, and... May 2021To systematically evaluate the evidence regarding the effects of foods on LDL cholesterol levels and to compare the findings with current guidelines. (Meta-Analysis)
Meta-Analysis
AIMS
To systematically evaluate the evidence regarding the effects of foods on LDL cholesterol levels and to compare the findings with current guidelines.
DATA SYNTHESIS
From inception through June 2019, we searched PubMed, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials for guidelines, systematic reviews, and RCTs (for coffee intake only) of at least 13 days duration. Additionally, we searched Trip database for guidelines from 2009 through Oct 2019. Language was restricted to English. The strength of evidence was evaluated using The Grading of Recommendations Assessment, Development, and Evaluation (GRADE). A total of 37 guidelines, 108 systematic reviews, and 20 RCTs were included. With high evidence, foods high in unsaturated and low in saturated and trans fatty acids (e.g. rapeseed/canola oil), with added plant sterols/stanols, and high in soluble fiber (e.g. oats, barley, and psyllium) caused at least moderate (i.e. 0.20-0.40 mmol/L) reductions in LDL cholesterol. Unfiltered coffee caused a moderate to large increase. Soy protein, tomatoes, flaxseeds, and almonds caused small reductions. With moderate evidence, avocados and turmeric caused moderate to large reductions. Pulses, hazelnuts, walnuts, high-fiber/wholegrain foods, and green tea caused small to moderate reductions, whereas sugar caused a small increase. Other identified foods were either neutral or had low or very low evidence regarding their effects.
CONCLUSIONS
Several foods distinctly modify LDL cholesterol levels. The results may aid future guidelines and dietary advice for hypercholesterolemia.
Topics: Adult; Biomarkers; Cholesterol, LDL; Diet; Diet, Healthy; Down-Regulation; Female; Humans; Hypercholesterolemia; Male; Middle Aged; Nutritive Value; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Risk Reduction Behavior; Treatment Outcome; Young Adult
PubMed: 33762150
DOI: 10.1016/j.numecd.2020.12.032 -
JAMA Network Open Nov 2023Increasing evidence suggests that, compared with an omnivorous diet, a vegan diet confers potential cardiovascular benefits from improved diet quality (ie, higher... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
Increasing evidence suggests that, compared with an omnivorous diet, a vegan diet confers potential cardiovascular benefits from improved diet quality (ie, higher consumption of vegetables, legumes, fruits, whole grains, nuts, and seeds).
OBJECTIVE
To compare the effects of a healthy vegan vs healthy omnivorous diet on cardiometabolic measures during an 8-week intervention.
DESIGN, SETTING, AND PARTICIPANTS
This single-center, population-based randomized clinical trial of 22 pairs of twins (N = 44) randomized participants to a vegan or omnivorous diet (1 twin per diet). Participant enrollment began March 28, 2022, and continued through May 5, 2022. The date of final follow-up data collection was July 20, 2022. This 8-week, open-label, parallel, dietary randomized clinical trial compared the health impact of a vegan diet vs an omnivorous diet in identical twins. Primary analysis included all available data.
INTERVENTION
Twin pairs were randomized to follow a healthy vegan diet or a healthy omnivorous diet for 8 weeks. Diet-specific meals were provided via a meal delivery service from baseline through week 4, and from weeks 5 to 8 participants prepared their own diet-appropriate meals and snacks.
MAIN OUTCOMES AND MEASURES
The primary outcome was difference in low-density lipoprotein cholesterol concentration from baseline to end point (week 8). Secondary outcome measures were changes in cardiometabolic factors (plasma lipids, glucose, and insulin levels and serum trimethylamine N-oxide level), plasma vitamin B12 level, and body weight. Exploratory measures were adherence to study diets, ease or difficulty in following the diets, participant energy levels, and sense of well-being.
RESULTS
A total of 22 pairs (N = 44) of twins (34 [77.3%] female; mean [SD] age, 39.6 [12.7] years; mean [SD] body mass index, 25.9 [4.7]) were enrolled in the study. After 8 weeks, compared with twins randomized to an omnivorous diet, the twins randomized to the vegan diet experienced significant mean (SD) decreases in low-density lipoprotein cholesterol concentration (-13.9 [5.8] mg/dL; 95% CI, -25.3 to -2.4 mg/dL), fasting insulin level (-2.9 [1.3] μIU/mL; 95% CI, -5.3 to -0.4 μIU/mL), and body weight (-1.9 [0.7] kg; 95% CI, -3.3 to -0.6 kg).
CONCLUSIONS AND RELEVANCE
In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT05297825.
Topics: Adult; Female; Humans; Male; Body Weight; Cardiovascular Diseases; Cholesterol, LDL; Diet, Vegan; Insulins; Twins, Monozygotic; Vegetables; Middle Aged; Diet, Healthy
PubMed: 38032644
DOI: 10.1001/jamanetworkopen.2023.44457 -
Dietary Cholesterol and Cardiovascular Risk: A Science Advisory From the American Heart Association.Circulation Jan 2020The elimination of specific dietary cholesterol target recommendations in recent guidelines has raised questions about its role with respect to cardiovascular disease.... (Meta-Analysis)
Meta-Analysis
The elimination of specific dietary cholesterol target recommendations in recent guidelines has raised questions about its role with respect to cardiovascular disease. This advisory was developed after a review of human studies on the relationship of dietary cholesterol with blood lipids, lipoproteins, and cardiovascular disease risk to address questions about the relevance of dietary cholesterol guidance for heart health. Evidence from observational studies conducted in several countries generally does not indicate a significant association with cardiovascular disease risk. Although meta-analyses of intervention studies differ in their findings, most associate intakes of cholesterol that exceed current average levels with elevated total or low-density lipoprotein cholesterol concentrations. Dietary guidance should focus on healthy dietary patterns (eg, Mediterranean-style and DASH [Dietary Approaches to Stop Hypertension]-style diets) that are inherently relatively low in cholesterol with typical levels similar to the current US intake. These patterns emphasize fruits, vegetables, whole grains, low-fat or fat-free dairy products, lean protein sources, nuts, seeds, and liquid vegetable oils. A recommendation that gives a specific dietary cholesterol target within the context of food-based advice is challenging for clinicians and consumers to implement; hence, guidance focused on dietary patterns is more likely to improve diet quality and to promote cardiovascular health.
Topics: Cardiovascular Diseases; Cholesterol, Dietary; Diet, Western; Humans; Nutrition Policy; Recommended Dietary Allowances
PubMed: 31838890
DOI: 10.1161/CIR.0000000000000743 -
Current Opinion in Gastroenterology Nov 2022Several recent studies have corroborated a strong association between diet and gastric cancer risk; investigators have also identified dietary factors that protect... (Review)
Review
PURPOSE OF REVIEW
Several recent studies have corroborated a strong association between diet and gastric cancer risk; investigators have also identified dietary factors that protect against gastric cancer. This review summarizes the literature on this topic and guides future research directions.
RECENT FINDINGS
High-salt intake disrupts the gastric mucosal defense barrier, promoting Helicobacter pylori colonization and penetration of other carcinogenic compounds. Processed foods, processed meats, red meat, alcohol, foods with high dietary fat, and dietary cholesterol increase the risk of gastric carcinogenesis. On the other hand, increased consumption of fruits, vegetables, whole grains, nuts, and a low-salt diet may offer a protective effect.
SUMMARY
Despite decreases in gastric cancer incidence because of increased identification and treatment of H. pylori , gastric cancer remains one of the most common cancers worldwide with a high mortality rate. This disturbing statistic highlights the importance of reducing and eliminating other risk factors for gastric cancer. There is a strong body of evidence that alcohol, processed foods, high salt intake, high fat intake, and foods with animal products (meats, eggs, and dairy) increase the risk of gastric cancer. A diet that is high in whole grains, fruits, vegetables, nuts and is low in salt may reduce the risk of gastric cancer.
Topics: Animals; Carcinogenesis; Cholesterol, Dietary; Diet; Dietary Fats; Helicobacter pylori; Humans; Risk Factors; Sodium Chloride, Dietary; Stomach Neoplasms; Vegetables
PubMed: 36165035
DOI: 10.1097/MOG.0000000000000875 -
Journal of Nutritional Science 2023Whilst dietary cholesterol guidelines have waivered through the years with historic restrictions lifted for the majority of the general population, recommendations to... (Review)
Review
Whilst dietary cholesterol guidelines have waivered through the years with historic restrictions lifted for the majority of the general population, recommendations to reduce saturated fat intake have been the mainstay of dietary guidelines since the 1980s and were recently reinforced by the Scientific Advisory Committee on Nutrition (SACN). Cholesterol metabolism is complex, with saturated fat known to have a more significant contribution at raising levels of low-density lipoprotein (LDL) cholesterol, a well-established risk factor for cardiovascular disease (CVD). However, it is clear from metabolic research that hyper-responsiveness to both dietary cholesterol and saturated fat exists; hence, for specific subsets of the population, reductions in both nutrients may be indicated. With this in mind, the current article aims to provide an overview of the mechanisms underlying biological variation in responsiveness and introduces research currently underway which will hopefully identify simple biomarkers that can be used to predict responsiveness and permit tailored, personalised, dietary advice. Eggs are a well-known source of dietary cholesterol whilst being low in saturated fat. A common question encountered in clinical practice is must individuals limit intake to manage blood cholesterol levels. This article summarises key recent papers which confirm that eggs can be enjoyed as part of a healthy balanced diet, whilst highlighting the need for further research in certain population groups, e.g. in individuals with diabetes.
Topics: Humans; Dietary Fats; Cholesterol, Dietary; Cardiovascular Diseases; Cholesterol; Diet
PubMed: 37706071
DOI: 10.1017/jns.2023.82 -
Current Opinion in Clinical Nutrition... Nov 2022Chronic noncommunicable diseases remain the leading cause of morbidity and mortality worldwide and the majority are preventable with a healthy diet and lifestyle, but... (Review)
Review
PURPOSE OF REVIEW
Chronic noncommunicable diseases remain the leading cause of morbidity and mortality worldwide and the majority are preventable with a healthy diet and lifestyle, but controversy remains as to the best approach. Greater adherence to a traditional Mediterranean diet has consistently been associated with lower morbidity and mortality from cardiovascular disease, diabetes and many cancers, and lower all-cause mortality. Despite the well known benefits on chronic disease risk there remains some scepticism as to the effects of this dietary pattern across populations outside the Mediterranean and the mechanisms of action of this traditional plant-based dietary pattern.This narrative review aims to summarize the latest evidence on the health protective effects of a traditional Mediterranean diet on chronic noncommunicable diseases, specifically focussing on the anti-inflammatory effects of this highly published dietary pattern.
RECENT FINDINGS
Recent high-quality evidence now supports a Mediterranean diet in secondary prevention of cardiovascular disease with impacts on atherosclerosis progression, likely through reduction of systemic inflammation and irrespective of changes in cholesterol or weight. The Mediterranean diet has a low Dietary Inflammatory Index illustrating its anti-inflammatory potential. This dietary pattern beneficially modulates the gut microbiota and immune system, including emerging evidence for efficacy against severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019). Emerging evidence shows clinicians are not routinely recommending a Mediterranean diet despite well known evidence due to barriers such as lack of training, patient materials and concerns about potential patient adherence.
SUMMARY
The physiological mechanisms of action of this healthy diet pattern are becoming better understood to be multisystem and involving the gut. Larger controlled trials investigating mechanistic effects in broader non-Mediterranean populations are warranted. Although reflected in therapeutic guidelines for chronic disease management worldwide there are individual, clinical practice and health system barriers to its implementation that need a multisectoral approach to address.
Topics: COVID-19; Cardiovascular Diseases; Cholesterol; Diet, Mediterranean; Humans; Noncommunicable Diseases
PubMed: 36039924
DOI: 10.1097/MCO.0000000000000872 -
Nutricion Hospitalaria Aug 2022Objective: to evaluate the lipid metabolism of patients with type 2 diabetes mellitus (T2DM) after very low-carbohydrate ketogenic (VLCK) diet treatment, so as to... (Meta-Analysis)
Meta-Analysis
Objective: to evaluate the lipid metabolism of patients with type 2 diabetes mellitus (T2DM) after very low-carbohydrate ketogenic (VLCK) diet treatment, so as to provide an evidence-based basis for better dietary management and comprehensive treatment of diabetic patients. Methods: PubMed, Cochrane Library, Embase, and Web of Science databases were searched for randomized controlled trial about VLCK diet on lipid metabolism of T2DM up to September 2021. The data were analyzed using the Stata 15.0; standardized mean difference (SMD) was used as effect size. Results: ten articles were included in this meta-analysis. There were no significant differences between the two groups in total cholesterol (SMD = -0.07, 95 % CI: -0.06-0.20, p > 0.05), HDL (SMD = 0.13, 95 % CI: -0.05-0.31, p > 0.05) and LDL (SMD = 0.07, 95 % CI: -0.06-0.20, p > 0.05) levels after treatment. No difference was found in total cholesterol, HDL, and LDL levels between the two groups after 3, 6, and 12 months of treatment (p > 0.05). Triglyceride levels decreased after VLCK diet compared with control (SMD = -0.49, 95 % CI: -0.82 to -0.17, p = 0.003). A marked reduction of triglyceride levels was identified after 3 months of VLCK diet treatment (SMD = -0.69, 95 % CI: -1.00 to -0.38), without significant difference after 6 and 12 months. Conclusion: T2DM patients who receive a VLCK diet to lower blood glucose are not associated with increased levels of total cholesterol and LDL, and decreased levels of HDL. Additionally, this diet can achieve a short-term reduction of triglyceride levels.
Topics: Blood Glucose; Cholesterol; Diabetes Mellitus, Type 2; Diet, Ketogenic; Humans; Lipid Metabolism; Lipids; Triglycerides
PubMed: 35243868
DOI: 10.20960/nh.03987