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The Proceedings of the Nutrition Society Aug 2016Vegetarians, who do not eat any meat, poultry or fish, constitute a significant minority of the world's population. Lacto-ovo-vegetarians consume dairy products and/or... (Review)
Review
Vegetarians, who do not eat any meat, poultry or fish, constitute a significant minority of the world's population. Lacto-ovo-vegetarians consume dairy products and/or eggs, whereas vegans do not eat any foods derived wholly or partly from animals. Concerns over the health, environmental and economic consequences of a diet rich in meat and other animal products have focussed attention on those who exclude some or all of these foods from their diet. There has been extensive research into the nutritional adequacy of vegetarian diets, but less is known about the long-term health of vegetarians and vegans. We summarise the main findings from large cross-sectional and prospective cohort studies in western countries with a high proportion of vegetarian participants. Vegetarians have a lower prevalence of overweight and obesity and a lower risk of IHD compared with non-vegetarians from a similar background, whereas the data are equivocal for stroke. For cancer, there is some evidence that the risk for all cancer sites combined is slightly lower in vegetarians than in non-vegetarians, but findings for individual cancer sites are inconclusive. Vegetarians have also been found to have lower risks for diabetes, diverticular disease and eye cataract. Overall mortality is similar for vegetarians and comparable non-vegetarians, but vegetarian groups compare favourably with the general population. The long-term health of vegetarians appears to be generally good, and for some diseases and medical conditions it may be better than that of comparable omnivores. Much more research is needed, particularly on the long-term health of vegans.
Topics: Body Mass Index; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Diet, Vegan; Diet, Vegetarian; Health Status; Humans; Neoplasms; Obesity; Prevalence; Risk Factors; Weight Gain
PubMed: 26707634
DOI: 10.1017/S0029665115004334 -
Obesity Reviews : An Official Journal... Sep 2022In parallel with an increased focus on climate changes and carbon footprint, the interest in plant-based diets and its potential health effects have increased over the... (Meta-Analysis)
Meta-Analysis Review
In parallel with an increased focus on climate changes and carbon footprint, the interest in plant-based diets and its potential health effects have increased over the past decade. The objective of this systematic review and meta-analysis was to examine the effect of vegan diets (≥12 weeks) on cardiometabolic risk factors in people with overweight or type 2 diabetes. We identified 11 trials (796 participants). In comparison with control diets, vegan diets reduced body weight (-4.1 kg, 95% confidence interval (CI) -5.9 to -2.4, p < 0.001), body mass index (BMI) (-1.38 kg/m , 95% CI -1.96 to -0.80, p < 0.001), glycated hemoglobin (HbA ) (-0.18% points, 95% CI -0.29 to -0.07, p = 0.002), total cholesterol (-0.30 mmol/L, 95% CI -0.52 to -0.08, p = 0.007), and low-density lipoprotein cholesterol (-0.24 mmol/L, 95% CI -0.40 to -0.07, p = 0.005). We identified no effect on blood pressure, high-density lipoprotein cholesterol, and triglycerides. We found that adhering to vegan diets for at least 12 weeks may be effective in individuals with overweight or type 2 diabetes to induce a meaningful decrease in body weight and improve glycemia. Some of this effect may be contributed to differences in the macronutrient composition and energy intake in the vegan versus control diets. Therefore, more research is needed regarding vegan diets and cardiometabolic health.
Topics: Body Weight; Cardiovascular Diseases; Cholesterol, HDL; Diabetes Mellitus, Type 2; Diet, Vegan; Humans; Overweight; Randomized Controlled Trials as Topic
PubMed: 35672940
DOI: 10.1111/obr.13462 -
Nutrients Apr 2020Unhealthy diet is a significant risk factor for cardiovascular diseases (CVD). Therefore, this umbrella review aims to comprehensively review the effects of dietary... (Review)
Review
Unhealthy diet is a significant risk factor for cardiovascular diseases (CVD). Therefore, this umbrella review aims to comprehensively review the effects of dietary factors, including dietary patterns, food groups, and nutrients on CVD risks. Medline and Scopus databases were searched through March 2020. Systematic reviews with meta-analyses (SRMA) of randomized controlled trials (RCTs) or observational studies measuring the effects of dietary factors on CVD risks were eligible. Fifty-four SRMAs, including 35 SRMAs of observational studies, 10 SRMAs of RCTs, and 9 SRMAs of combined RCT and observational studies, were included for review. Findings from the SRMAs of RCTs suggest the significant benefit of Mediterranean and high-quality diets for lowering CVD risk, with pooled risk ratios (RRs) ranging from 0.55 (95%CI: 0.39-0.76) to 0.64 (95%CI: 0.53-0.79) and 0.70 (95%CI: 0.57-0.87), respectively. For food nutrients, two SRMAs of RCTs found that high intake of n-3 polyunsaturated fatty acid (PUFA) significantly reduced CVD risks, with pooled RRs ranging from 0.89 (95%CI: 0.82, 0.98) to 0.90 (95%CI: 0.85-0.96), while evidence of efficacy of n-6 PUFA and combined n-3 and n-6 PUFA were inconsistent. Moreover, results from the SRMAs of RCTs did not find a significant benefit of a low-salt diet and low total fat intake for CVD prevention. For food groups, results from the SRMAs of cohort studies suggest that high intakes of legumes, nuts, and chocolate, as well as a vegetarian diet significantly reduced the risk of coronary heart disease, with pooled RRs of 0.90 (95%CI: 0.84-0.97), 0.68 (95%CI: 0.59-0.78), 0.90 (95%CI: 0.82-0.97), and 0.71 (95%CI: 0.57-0.87), respectively. Healthy dietary patterns had a significant benefit for CVD prevention. With the substitutional and synergistic interactions between different food groups and nutrients, dietary recommendations for CVD prevention should be focused more on healthy dietary patterns than single food groups or nutrients.
Topics: Cardiovascular Diseases; Chocolate; Diet, Fat-Restricted; Diet, Healthy; Diet, Mediterranean; Diet, Sodium-Restricted; Diet, Vegan; Fabaceae; Fatty Acids, Omega-3; Humans; Meta-Analysis as Topic; Nuts; Observational Studies as Topic; Randomized Controlled Trials as Topic; Risk Factors; Systematic Reviews as Topic
PubMed: 32326404
DOI: 10.3390/nu12041088 -
Nutrition Reviews Mar 2021Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive... (Meta-Analysis)
Meta-Analysis
CONTEXT
Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive impairment and mental health disorders have a high economic burden.
OBJECTIVE
A meta-analysis was conducted to examine the relationship between vegan or vegetarian diets and cognitive and mental health.
DATA SOURCES
PubMed, Scopus, ScienceDirect, and Proquest databases were examined from inception to July 2018.
STUDY SELECTION
Original observational or interventional human studies of vegan/vegetarian diets were selected independently by 2 authors.
DATA EXTRACTION
Raw means and standard deviations were used as continuous outcomes, while numbers of events were used as categorical outcomes.
RESULTS
Of 1249 publications identified, 13 were included, with 17 809 individuals in total. No significant association was found between diet and the continuous depression score, stress, well-being, or cognitive impairment. Vegans/vegetarians were at increased risk for depression (odds ratio = 2.142; 95%CI, 1.105-4.148) and had lower anxiety scores (mean difference = -0.847; 95%CI, -1.677 to -0.018). Heterogeneity was large, and thus subgroup analyses showed numerous differences.
CONCLUSIONS
Vegan or vegetarian diets were related to a higher risk of depression and lower anxiety scores, but no differences for other outcomes were found. Subgroup analyses of anxiety showed a higher risk of anxiety, mainly in participants under 26 years of age and in studies with a higher quality. More studies with better overall quality are needed to make clear positive or negative associations.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42018097204.
Topics: Anxiety; Cognition; Depression; Diet, Vegan; Diet, Vegetarian; Humans; Mental Health; Vegans; Vegetarians
PubMed: 32483598
DOI: 10.1093/nutrit/nuaa030 -
Nutrients Nov 2022Caloric restriction and vegan diets have demonstrated protective effects for diabetes, however their role in improving clinically relevant outcomes has not been... (Meta-Analysis)
Meta-Analysis Review
Investigating the Effectiveness of Very Low-Calorie Diets and Low-Fat Vegan Diets on Weight and Glycemic Markers in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis.
Caloric restriction and vegan diets have demonstrated protective effects for diabetes, however their role in improving clinically relevant outcomes has not been summarized. Our aim was to evaluate the evidence for low-calorie diets (VLCD) and vegan diets on weight and glycemic control in the management of patients with Type 2 Diabetes. Database searches were conducted using Cochrane Library, MEDLINE (Ovid) and Embase. Systematic Review Registration: CRD42022310299. Methodological quality of studies was assessed using Cochrane RoB Tool for RCTs, Cochrane ROBINS-I RoB Tool for non-RCTs and NIH Quality Assessment tool for other studies. Sixteen studies with a total of 834 individuals were included and assessed to have a moderate to high risk of bias. Statistically significant changes in weight, BMI, and HbA1c were not observed in vegan diet cohorts. However, LDL cholesterol was significantly decreased by vegan diet. VLCDs significantly improved glycaemic control, with reductions in fasting glucose, pooled mean difference (MD) -1.51 mmol/L (95% CI -2.89, -0.13; = 0.03; 2 studies) and HbA1c, pooled MD -0.66% (95% CI -1.28, -0.03; = 0.04; 3 studies) compared to non-dietary therapy. Both diets suggested a trend towards improved weight loss and anthropometric markers vs. control. VLCD diet intervention is associated with improvement in glycaemia control in patients with Type 2 Diabetes.
Topics: Humans; Diet, Vegan; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Caloric Restriction; Blood Glucose; Diet, Fat-Restricted; Biomarkers
PubMed: 36432557
DOI: 10.3390/nu14224870 -
The American Journal of Clinical... Nov 2022Low-carbohydrate, high animal fat and protein diets have been promoted for weight loss and diabetes treatment. We therefore tested the effect of a low-carbohydrate vegan... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Low-carbohydrate, high animal fat and protein diets have been promoted for weight loss and diabetes treatment. We therefore tested the effect of a low-carbohydrate vegan diet in diabetes as a potentially healthier and more ecologically sustainable low-carbohydrate option.
OBJECTIVES
We sought to compare the effectiveness of a low-carbohydrate vegan diet with a moderate-carbohydrate vegetarian diet on weight loss and metabolic measures in diabetes.
METHODS
One hundred and sixty-four male and female participants with type 2 diabetes were randomly assigned to advice on either a low-carbohydrate vegan diet, high in canola oil and plant proteins, or a vegetarian therapeutic diet, for 3 mo, with both diets recommended at 60% of calorie requirements. Body weight, fasting blood, blood pressure, and 7-d food records, to estimate potential greenhouse gas emissions, were obtained throughout the study with tests of cholesterol absorption undertaken at baseline and end of study on 50 participants.
RESULTS
Both low-carbohydrate vegan and vegetarian diets similarly but markedly reduced body weight (-5.9 kg; 95% CI: -6.5, -5.28 kg; and -5.23 kg; 95% CI: -5.84, -4.62 kg), glycated hemoglobin (-0.99%; 95% CI: -1.07, -0.9%; and -0.88%; 95% CI: -0.97, -0.8%), systolic blood pressure (-4 mmHg; 95% CI: -7, -2 mmHg; and -6 mmHg; 95% CI: -8, -3 mmHg), and potential greenhouse gas emissions, but only for potential greenhouse gas emissions was there a significant treatment difference of -0.63 kgCO/d (95% CI: -0.99, -0.27 kgCO/d) favoring the low-carbohydrate vegan diet.
CONCLUSIONS
Low-carbohydrate vegan and vegetarian diets reduced body weight, improved glycemic control and blood pressure, but the more plant-based diet had greater potential reduction in greenhouse gas emissions.
TRIAL REGISTRATION NUMBER
clinicaltrials.gov identifier NCT02245399.
Topics: Humans; Diet, Vegan; Diabetes Mellitus, Type 2; Vegans; Greenhouse Gases; Blood Glucose; Weight Loss; Body Weight; Diet, Carbohydrate-Restricted
PubMed: 36156115
DOI: 10.1093/ajcn/nqac203 -
Nutrients Mar 2021Despite being a focal issue to patients, the effect of diet on adult inflammatory bowel disease (IBD) remains underexplored with limited guidance. While promising... (Review)
Review
Despite being a focal issue to patients, the effect of diet on adult inflammatory bowel disease (IBD) remains underexplored with limited guidance. While promising clinical trials are currently underway, there is a need for further evidence-based recommendations. As such, we summarize the current evidence on various diets used in the treatment of IBD and also explore the potential applications of dietary data from related immune-mediated inflammatory diseases (IMIDs), such as rheumatoid arthritis and psoriasis, to provide additional information to inform IBD providers. To date, there have been multiple diets investigated as adjunctive therapy in IBD, but many associated studies are small, non-randomized, and not controlled. Mediterranean, vegetarian/vegan, and reduced-calorie/fasting diets have been studied and have shown some positive results in other IMIDs, which may suggest potential applicability to those with IBD, but larger, well-designed clinical trials are needed for further guidance. Gluten-free and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP)diets do not appear to have an impact on IBD disease activity, but low FODMAP may potentially be helpful for those with concurrent functional gastrointestinal symptoms. Specific carbohydrate diets have been mainly assessed in children but show some potential in small adult studies.
Topics: Arthritis, Rheumatoid; Caloric Restriction; Diet; Diet, Carbohydrate-Restricted; Diet, Gluten-Free; Diet, High-Protein Low-Carbohydrate; Diet, Mediterranean; Diet, Paleolithic; Diet, Vegan; Diet, Vegetarian; Fasting; Humans; Inflammatory Bowel Diseases; Psoriasis
PubMed: 33801883
DOI: 10.3390/nu13030890 -
European Journal of Nutrition Apr 2023Vitamin B is an essential nutrient that is not made by plants; consequently, unfortified plant-based foods are not a reliable supply. Recent estimates suggest high rates...
Vitamin B is an essential nutrient that is not made by plants; consequently, unfortified plant-based foods are not a reliable supply. Recent estimates suggest high rates of vitamin B deficiency among the vegetarian and vegan populations, particularly in pregnant women or women of child-bearing age who, for ethical and health reasons, are shifting towards higher consumption of plant-based foods in ever-increasing numbers. Vitamin B plays crucial metabolic roles across the life-course and in particular during pregnancy and in early development (first 1000 days of life). Evidence now implicates vitamin B deficiency with increased risk to a range of neuro, vascular, immune, and inflammatory disorders. However, the current UK recommended nutrient intake for vitamin B does not adequately consider the vitamin B deficit for those choosing a plant-based diet, including vegetarianism and in particular veganism, representing a hidden hunger. We provide a cautionary note on the importance of preventing vitamin B deficits for those individuals choosing a plant-based diet and the health professionals advising them.
Topics: Humans; Female; Pregnancy; Vitamin B 12; Diet; Diet, Vegetarian; Diet, Vegan; Vitamins
PubMed: 36469110
DOI: 10.1007/s00394-022-03025-4 -
Nutrition Reviews Mar 2019Vegetarian diets are consistently associated with improved health outcomes, and higher diet quality may contribute to improved health outcomes. This systematic review...
OBJECTIVE
Vegetarian diets are consistently associated with improved health outcomes, and higher diet quality may contribute to improved health outcomes. This systematic review aims to qualitatively compare the a priori diet quality of vegetarian and nonvegetarian diets.
METHODS
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, 2 online databases (Web of Science and PubMed) were searched for English language studies comparing diet quality among vegetarian and nonvegetarian adults using an a priori diet quality index. Two reviewers assessed study eligibility. Comparisons were made between total and component (when available) diet quality scores among the 12 studies meeting inclusion criteria.
CONCLUSIONS
Lacto-ovo vegetarians or vegans had higher overall diet quality (4.5-16.4 points higher on the Healthy Eating Index 2010 [HEI-2010]) compared with nonvegetarians in 9 of 12 studies. Higher HEI-2010 scores for vegetarians were driven by closer adherence to recommendations for total fruit, whole grains, seafood and plant protein, and sodium. However, nonvegetarians had closer adherence to recommendations for refined grains and total protein foods. Higher diet quality in vegetarian diets may partially explain improvements in health outcomes compared with nonvegetarians; however, more research controlling for known confounders like health consciousness is needed.
Topics: Adult; Diet; Diet, Vegan; Diet, Vegetarian; Female; Fruit; Humans; Male; Middle Aged; Minerals; Nutritive Value; Young Adult
PubMed: 30624697
DOI: 10.1093/nutrit/nuy067 -
Nutrients Apr 2019Due to the lack of current, large-scale studies examining their dietary intake and health, there are concerns about vegetarian (VG) and vegan (VN) diets in childhood....
Due to the lack of current, large-scale studies examining their dietary intake and health, there are concerns about vegetarian (VG) and vegan (VN) diets in childhood. Therefore, the Vegetarian and Vegan Children Study (VeChi Diet Study) examined the energy and macronutrient intake as well as the anthropometrics of 430 VG, VN, and omnivorous (OM) children (1⁻3 years) in Germany. A 3-day weighed dietary record assessed dietary intake, and an online questionnaire assessed lifestyle, body weight (BW), and height. Average dietary intakes and anthropometrics were compared between groups using ANCOVA. There were no significant differences in energy intake or density and anthropometrics between the study groups. OM children had the highest adjusted median intakes of protein (OM: 2.7, VG: 2.3, VN: 2.4 g/kg BW, < 0.0001), fat (OM: 36.0, VG: 33.5, VN: 31.2%E, < 0.0001), and added sugars (OM: 5.3, VG: 4.5, VN: 3.8%E, = 0.002), whereas VN children had the highest adjusted intakes of carbohydrates (OM: 50.1, VG: 54.1, VN: 56.2%E, < 0.0001) and fiber (OM: 12.2, VG: 16.5, VN: 21.8 g/1,000 kcal, < 0.0001). Therefore, a VG and VN diet in early childhood can provide the same amount of energy and macronutrients, leading to a normal growth in comparison to OM children.
Topics: Analysis of Variance; Anthropometry; Body Height; Body Weight; Child Nutritional Physiological Phenomena; Child, Preschool; Cohort Studies; Cross-Sectional Studies; Diet Records; Diet, Vegan; Diet, Vegetarian; Energy Intake; Feeding Behavior; Female; Germany; Humans; Infant; Life Style; Male; Nutrients; Nutritional Status; Surveys and Questionnaires; Vegans; Vegetarians
PubMed: 31013738
DOI: 10.3390/nu11040832