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Nutrition Bulletin Mar 2022Recent evidence suggests that vegetarian and vegan diets may increase the risk and symptoms of depression, a mental health condition affecting 350 million people... (Review)
Review
Recent evidence suggests that vegetarian and vegan diets may increase the risk and symptoms of depression, a mental health condition affecting 350 million people globally. We aimed to systematically review the literature on the associations between vegetarian and/or vegan diets and the risk or symptoms of depression using evidence from both observational and intervention studies. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with pre-specification of all methods. A systematic search for relevant papers was performed on Medline and Embase, Web of Science and the Cochrane Library for cohort, case-control, cross-sectional studies or randomised controlled trials examining associations between a vegetarian or vegan diet and depression in adults. Three independent reviewers extracted data and assessed risk of bias using the National Heart, Lung, and Blood Institute of the National Institutes of Health for Quality Assessment of Observational Cohort and Cross-Sectional Studies and Controlled Studies. Evidence was tabulated according to the type of diet analysed as vegetarian, vegan or both and narratively synthesised. A total of 23 studies (18 cross-sectional, three prospective cohort and two randomised controlled trials) with 25 study outcomes were eligible for inclusion in this review. Conflicting evidence was found on the association between vegetarian or vegan diets and depression. Eleven (44%) of the outcomes indicated that vegetarian and vegan diets were associated with higher rates of depression, while seven (28%) outcomes revealed beneficial effects of the diets on depression. Seven (28%) outcomes found no association between vegetarian and vegan diets and depression, although two of these studies found a higher risk of depression in some groups. The quality of evidence was rated as good for four of the studies with the remaining 19 studies rated as fair. The evidence on the effect of vegetarian and vegan diets on depression is contradictory, possibly due to the heterogeneity of the studies analysed. Further research, including longitudinal and intervention studies, is required to resolve this observation.
Topics: Adult; Cross-Sectional Studies; Depression; Diet, Vegan; Diet, Vegetarian; Humans; Prospective Studies; Randomized Controlled Trials as Topic; United States; Vegetarians
PubMed: 36045075
DOI: 10.1111/nbu.12540 -
BJOG : An International Journal of... Apr 2015Although vegan-vegetarian diets are increasingly popular, no recent systematic reviews on vegan-vegetarian diets in pregnancy exist. (Review)
Review
BACKGROUND
Although vegan-vegetarian diets are increasingly popular, no recent systematic reviews on vegan-vegetarian diets in pregnancy exist.
OBJECTIVES
To review the literature on vegan-vegetarian diets and pregnancy outcomes.
SEARCH STRATEGY
PubMed, Embase, and the Cochrane library were searched from inception to September 2013 for pregnancy and vegan or vegetarian Medical Subject Headings (MeSH) and free-text terms.
SELECTION CRITERIA
Vegan or vegetarian diets in healthy pregnant women. We excluded case reports and papers analysing vegan-vegetarian diets in poverty and malnutrition. Searching, paper selection, and data extraction were performed in duplicate.
DATA COLLECTION AND ANALYSIS
The high heterogeneity of the studies led to a narrative review.
MAIN RESULTS
We obtained 262 full texts from 2329 references; 22 selected papers reporting maternal-fetal outcomes (13) and dietary deficiencies (nine) met the inclusion criteria. None of the studies reported an increase in severe adverse outcomes or in major malformations, except one report of increased hypospadias in infants of vegetarian mothers. Five studies reported vegetarian mothers had lower birthweight babies, yet two studies reported higher birthweights. The duration of pregnancy was available in six studies and was similar between vegan-vegetarians and omnivores. The nine heterogeneous studies on microelements and vitamins suggest vegan-vegetarian women may be at risk of vitamin B12 and iron deficiencies.
AUTHOR'S CONCLUSIONS
The evidence on vegan-vegetarian diets in pregnancy is heterogeneous and scant. The lack of randomised studies prevents us from distinguishing the effects of diet from confounding factors. Within these limits, vegan-vegetarian diets may be considered safe in pregnancy, provided that attention is paid to vitamin and trace element requirements.
Topics: Confounding Factors, Epidemiologic; Diet, Vegetarian; Dietary Proteins; Feeding Behavior; Female; Humans; Maternal Nutritional Physiological Phenomena; Nutrition Policy; Nutritional Requirements; Pregnancy; Pregnancy Outcome; Risk Factors; Vitamins
PubMed: 25600902
DOI: 10.1111/1471-0528.13280 -
Nutrients Aug 2020Fibromyalgia (FM) is a multifactorial syndrome of unknown etiology, characterized by widespread chronic pain and various somatic and psychological manifestations. The...
Fibromyalgia (FM) is a multifactorial syndrome of unknown etiology, characterized by widespread chronic pain and various somatic and psychological manifestations. The management of FM requires a multidisciplinary approach combining both pharmacological and nonpharmacological strategies. Among nonpharmacological strategies, growing evidence suggests a potential beneficial role for nutrition. This review summarizes the possible relationship between FM and nutrition, exploring the available evidence on the effect of dietary supplements and dietary interventions in these patients. Analysis of the literature has shown that the role of dietary supplements remains controversial, although clinical trials with vitamin D, magnesium, iron and probiotics' supplementation show promising results. With regard to dietary interventions, the administration of olive oil, the replacement diet with ancient grains, low-calorie diets, the low FODMAPs diet, the gluten-free diet, the monosodium glutamate and aspartame-free diet, vegetarian diets as well as the Mediterranean diet all appear to be effective in reducing the FM symptoms. These results may suggest that weight loss, together with the psychosomatic component of the disease, should be taken into account. Therefore, although dietary aspects appear to be a promising complementary approach to the treatment of FM, further research is needed to provide the most effective strategies for the management of FM.
Topics: Acetylcarnitine; Ascorbic Acid; Chlorella; Diet, Vegan; Dietary Supplements; Fibromyalgia; Nutrition Therapy; Nutritional Physiological Phenomena; Syndrome; Ubiquinone; Vitamin E
PubMed: 32825400
DOI: 10.3390/nu12092525 -
Nutrients Aug 2022During the complementary feeding period, any nutritional deficiencies may negatively impact infant growth and neurodevelopment. A healthy diet containing all essential... (Review)
Review
During the complementary feeding period, any nutritional deficiencies may negatively impact infant growth and neurodevelopment. A healthy diet containing all essential nutrients is strongly recommended by the WHO during infancy. Because vegetarian diets are becoming increasingly popular in many industrialized countries, some parents ask the pediatrician for a vegetarian diet, partially or entirely free of animal-source foods, for their children from an early age. This systematic review aims to evaluate the evidence on how vegetarian complementary feeding impacts infant growth, neurodevelopment, risk of wasted and/or stunted growth, overweight and obesity. The SR was registered with PROSPERO 2021 (CRD 42021273592). A comprehensive search strategy was adopted to search and find all relevant studies. For ethical reasons, there are no interventional studies assessing the impact of non-supplemented vegetarian/vegan diets on the physical and neurocognitive development of children, but there are numerous studies that have analyzed the effects of dietary deficiencies on individual nutrients. Based on current evidence, vegetarian and vegan diets during the complementary feeding period have not been shown to be safe, and the current best evidence suggests that the risk of critical micronutrient deficiencies or insufficiencies and growth retardation is high: they may result in significantly different outcomes in neuropsychological development and growth when compared with a healthy omnivorous diet such as the Mediterranean Diet. There are also no data documenting the protective effect of vegetarian or vegan diets against communicable diseases in children aged 6 months to 2-3 years.
Topics: Animals; Diet, Vegan; Diet, Vegetarian; Eating; Humans; Infant; Infant Nutritional Physiological Phenomena; Malnutrition; Vegetarians
PubMed: 36079848
DOI: 10.3390/nu14173591 -
Nutrients Aug 2020Fibromyalgia syndrome (FMS) is characterised by chronic widespread pain alongside fatigue, poor sleep quality and numerous comorbidities. It is estimated to have a...
Fibromyalgia syndrome (FMS) is characterised by chronic widespread pain alongside fatigue, poor sleep quality and numerous comorbidities. It is estimated to have a worldwide prevalence of 1.78%, with a predominance in females. Treatment interventions for fibromyalgia have limited success, leading to many patients seeking alternative forms of treatment, including modifications to their diet and lifestyle. The effectiveness of dietary changes in fibromyalgia has not been widely researched or evaluated. This systematic review identified twenty-two studies, including 18 randomised control trials (RCTs) and four cohort studies which were eligible for inclusion. In total these studies investigated 17 different nutritional interventions. Significant improvements in reported pain were observed for those following a vegan diet, as well as with the low fermentable oligo di-mono-saccharides and polyols (FODMAP) diets. Supplementation with green algae, coenzyme Q10, acetyl-l-carnitine or a combination of vitamin C and E significantly improved measures of pain. Interpretation of these studies was limited due to the frequent poor quality of the study design, the wide heterogeneity between studies, the small sample size and a high degree of bias. Therefore, there is insufficient evidence to recommend any one particular nutritional intervention for the management of fibromyalgia and further research is needed.
Topics: Acetylcarnitine; Ascorbic Acid; Chlorella; Diet, Vegan; Dietary Supplements; Fermented Foods; Fibromyalgia; Humans; Nigella sativa; Pain; Phytotherapy; Quality of Life; Randomized Controlled Trials as Topic; Seeds; Treatment Outcome; Ubiquinone; Vitamin E
PubMed: 32878326
DOI: 10.3390/nu12092664 -
Nutrients Jul 2021The human gut microbiota are the microorganisms (generally bacteria and archaea) that live in the digestive tracts of humans. Due to their numerous functions, the gut...
The human gut microbiota are the microorganisms (generally bacteria and archaea) that live in the digestive tracts of humans. Due to their numerous functions, the gut microbiota can be considered a virtual organ of the body, playing a pivotal role in health maintenance. Dietary habits contribute to gut microbiota composition, and evidence from observational and intervention studies suggest that vegan diets may promote health, potentially through affecting the diverse ecosystem of beneficial bacteria in the gut. A systematic literature search was conducted on PubMed and Scopus to identify studies investigating the microbiota composition in vegans. Vegans are defined as people excluding food products that are derived from animals from their diet. Nine observational studies were identified. The main outcome of the systematic review was an increase in Bacteroidetes on the phylum level and a higher abundance of on the genus level. In conclusion, the present systematic literature review highlighted some benefits of a vegan diet but also demonstrated the complexity of evaluating results from gut microbiota research. The available evidence only consisted of cross-sectional studies, therefore suggesting the need for well-designed randomised controlled trials. Furthermore, the quality assessment of the studies included in the review suggested a lack of standardised and validated methods for participant selection as well as for faecal sampling and faecal analysis.
Topics: Adult; Bacteria; Diet, Healthy; Diet, Vegan; Dysbiosis; Feces; Female; Gastrointestinal Microbiome; Humans; Intestines; Male; Middle Aged; Nutritive Value
PubMed: 34371912
DOI: 10.3390/nu13072402 -
Health aspects of vegan diets among children and adolescents: a systematic review and meta-analyses.Critical Reviews in Food Science and... Oct 2023Health effects of vegan diets among children and adolescents are a controversial public health topic. Thus, the aim of the present systematic review is to evaluate a... (Review)
Review
Health effects of vegan diets among children and adolescents are a controversial public health topic. Thus, the aim of the present systematic review is to evaluate a broad range of health outcomes among vegan children and adolescents aged 0 to 18 years. 18 studies met the inclusion criteria (17 cross-sectional, 1 RCT). Meta-analyses showed lower protein, calcium, vitamin B2, saturated fatty acid, and cholesterol intakes, and lower ferritin, HDL and LDL levels as well as height in vegan compared to omnivorous children/adolescents. Higher intakes of carbohydrates, polyunsaturated fatty acids, fiber, folate, vitamins C and E, magnesium, iron, and potassium were observed in vegans. Blood levels of vitamin B12 were higher among vegan children due to supplement use. Single study results suggested further differences between vegan and non-vegan children, such as lower bone mineral content or urinary iodine among vegan children. Risk of Bias was rated as high or very high in 7 out of 18 studies. The certainty of evidence for the meta-analyses was low ( = 2) or very low ( = 46). Overall, the available evidence points to both risks and benefits associated with a vegan diet among children, although more and better designed studies are needed.
PubMed: 37811643
DOI: 10.1080/10408398.2023.2263574 -
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 -
European Heart Journal Jul 2023Due to growing environmental focus, plant-based diets are increasing steadily in popularity. Uncovering the effect on well-established risk factors for cardiovascular... (Meta-Analysis)
Meta-Analysis
AIMS
Due to growing environmental focus, plant-based diets are increasing steadily in popularity. Uncovering the effect on well-established risk factors for cardiovascular diseases, the leading cause of death worldwide, is thus highly relevant. Therefore, a systematic review and meta-analysis were conducted to estimate the effect of vegetarian and vegan diets on blood levels of total cholesterol, low-density lipoprotein cholesterol, triglycerides, and apolipoprotein B.
METHODS AND RESULTS
Studies published between 1980 and October 2022 were searched for using PubMed, Embase, and references of previous reviews. Included studies were randomized controlled trials that quantified the effect of vegetarian or vegan diets vs. an omnivorous diet on blood lipids and lipoprotein levels in adults over 18 years. Estimates were calculated using a random-effects model. Thirty trials were included in the study. Compared with the omnivorous group, the plant-based diets reduced total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B levels with mean differences of -0.34 mmol/L (95% confidence interval, -0.44, -0.23; P = 1 × 10-9), -0.30 mmol/L (-0.40, -0.19; P = 4 × 10-8), and -12.92 mg/dL (-22.63, -3.20; P = 0.01), respectively. The effect sizes were similar across age, continent, duration of study, health status, intervention diet, intervention program, and study design. No significant difference was observed for triglyceride levels.
CONCLUSION
Vegetarian and vegan diets were associated with reduced concentrations of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B-effects that were consistent across various study and participant characteristics. Plant-based diets have the potential to lessen the atherosclerotic burden from atherogenic lipoproteins and thereby reduce the risk of cardiovascular disease.
Topics: Adult; Humans; Diet, Vegan; Diet, Vegetarian; Randomized Controlled Trials as Topic; Lipids; Vegetarians; Cholesterol, LDL; Lipoproteins; Cardiovascular Diseases; Atherosclerosis; Apolipoproteins
PubMed: 37226630
DOI: 10.1093/eurheartj/ehad211 -
Nutrition, Metabolism, and... Jun 2019The aim of the present review is to examine evidence from published studies on the effectiveness of six or more months of low carbohydrate, macrobiotic, vegan,...
BACKGROUND AND AIM
The aim of the present review is to examine evidence from published studies on the effectiveness of six or more months of low carbohydrate, macrobiotic, vegan, vegetarian, Mediterranean and intermittent fasting (IF) diets compared to low fat diets on diabetes control and management.
METHODS AND RESULTS
In accordance with PRISMA guidelines, Cochrane CENTRAL, PubMed and Scopus databases were systematically searched for relevant studies. Twenty randomised controlled trials (RCTs) > 6 months that investigated the effectiveness of various dietary patterns on type 2 diabetes mellitus (T2DM) were included. Risk of bias was assessed using the Cochrane tool. There were no significant differences in glycemic control, weight and lipids for the majority of low carbohydrate diets (LCDs) compared to low fat diets (LFDs). Four out of fifteen LCD interventions showed better glycemic control while weight loss was greater in one study. The Mediterranean dietary pattern demonstrated greater reduction in body weight and HbA1c levels and delayed requirement for diabetes medications. The vegan and macrobiotic diet demonstrated improved glycemic control, while the vegetarian diet showed greater body weight reduction and insulin sensitivity.
CONCLUSIONS
Although more long-term intervention trials are required, mounting evidence supports the view that vegan, vegetarian and Mediterranean dietary patterns should be implemented in public health strategies, in order to better control glycemic markers in individuals with T2DM.
Topics: Biomarkers; Blood Glucose; Diabetes Mellitus, Type 2; Diet, Diabetic; Diet, Healthy; Diet, Mediterranean; Diet, Vegan; Diet, Vegetarian; Humans; Insulin Resistance; Nutritional Status; Randomized Controlled Trials as Topic; Treatment Outcome; Weight Loss
PubMed: 30952576
DOI: 10.1016/j.numecd.2019.02.004