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Nutrients Nov 2019While animal products are rich in protein, the adequacy of dietary protein intake from vegetarian/vegan diets has long been controversial. In this review, we examine the... (Review)
Review
While animal products are rich in protein, the adequacy of dietary protein intake from vegetarian/vegan diets has long been controversial. In this review, we examine the protein and amino acid intakes from vegetarian diets followed by adults in western countries and gather information in terms of adequacy for protein and amino acids requirements, using indirect and direct data to estimate nutritional status. We point out that protein-rich foods, such as traditional legumes, nuts and seeds, are sufficient to achieve full protein adequacy in adults consuming vegetarian/vegan diets, while the question of any amino acid deficiency has been substantially overstated. Our review addresses the adequacy in changes to protein patterns in people newly transitioning to vegetarian diets. We also specifically address this in older adults, where the issues linked to the protein adequacy of vegetarian diets are more complex. This contrasts with the situation in children where there are no specific concerns regarding protein adequacy because of their very high energy requirements compared to those of protein. Given the growing shifts in recommendations from nutrition health professionals for people to transition to more plant-based, whole-food diets, additional scientific evidence-based communications confirming the protein adequacy of vegetarian and vegan diets is warranted.
Topics: Diet, Vegetarian; Dietary Proteins; Humans; Nutritional Requirements
PubMed: 31690027
DOI: 10.3390/nu11112661 -
Clinical Nutrition (Edinburgh, Scotland) May 2021Vegan diets, where animal- and all their by-products are excluded from the diet, have gained popularity, especially in the last decade. However, the evaluation of this...
BACKGROUND
Vegan diets, where animal- and all their by-products are excluded from the diet, have gained popularity, especially in the last decade. However, the evaluation of this type of diet has not been well addressed in the scientific literature. This study aimed to investigate the adequacy of vegan diets in European populations and of their macro- and micronutrient intakes compared to World Health Organization recommendations.
METHODS
A systematic search in PubMed, Web of Science, IBSS, Cochrane library and Google Scholar was conducted and 48 studies (12 cohorts and 36 cross-sectional) were included.
RESULTS
Regarding macronutrients, vegan diets are lower in protein intake compared with all other diet types. Veganism is also associated with low intake of vitamins B, Niacin (B), B, D, iodine, zinc, calcium, potassium, selenium. Vitamin B intake among vegans is significantly lower (0.24-0.49 μg, recommendations are 2.4 μg) and calcium intake in the majority of vegans was below recommendations (750 mg/d). No significant differences in fat intake were observed. Vegan diets are not related to deficiencies in vitamins A, B, Β, C, E, iron, phosphorus, magnesium, copper and folate and have a low glycemic load.
CONCLUSIONS
Following a vegan diet may result in deficiencies in micronutrients (vitamin B, zinc, calcium and selenium) which should not be disregarded. However, low micro- and macronutrient intakes are not always associated with health impairments. Individuals who consume a vegan diet should be aware of the risk of potential dietary deficiencies.
Topics: Adolescent; Adult; Aged; Diet, Vegan; Europe; Female; Humans; Male; Middle Aged; Nutrients; Nutritive Value; Vitamins; Young Adult
PubMed: 33341313
DOI: 10.1016/j.clnu.2020.11.035 -
European Journal of Nutrition Feb 2023Vegetarian diets have been associated with reduced risk of ischemic heart disease (IHD). However, results regarding cardiovascular disease (CVD) overall and stroke are... (Meta-Analysis)
Meta-Analysis Review
PURPOSE
Vegetarian diets have been associated with reduced risk of ischemic heart disease (IHD). However, results regarding cardiovascular disease (CVD) overall and stroke are less clear. We conducted a systematic review and meta-analysis of prospective cohort studies on CVD, IHD and stroke risk among vegetarians or vegans versus nonvegetarians to clarify these associations.
METHODS
PubMed and Ovid Embase databases were searched through August 12, 2021. Prospective cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for incidence or mortality from CVD, IHD and stroke, comparing vegetarians and vegans to nonvegetarians were included. Risk of bias (RoB) was assessed using ROBINS-I and the strength of evidence was assessed using World Cancer Research Fund (WCRF) criteria. Summary RRs (95% CIs) were estimated using a random effects model.
RESULTS
Thirteen cohort studies (844,175 participants, 115,392 CVD, 30,377 IHD, and 14,419 stroke cases) were included. The summary RR for vegetarians vs. nonvegetarians was 0.85 (95% CI: 0.79-0.92, I = 68%, n = 8) for CVD, 0.79 (95% CI: 0.71-0.88, I = 67%, n = 8) for IHD, 0.90 (95% CI: 0.77-1.05, I = 61%, n = 12) for total stroke, and for vegans vs. nonvegetarians was 0.82 (95% CI: 0.68-1.00, I = 0%, n = 6) for IHD. RoB was moderate (n = 8) to serious (n = 5). The associations between vegetarian diets and CVD and IHD were considered probably causal using WCRF criteria.
CONCLUSIONS
Vegetarian diets are associated with reduced risk of CVD and IHD, but not stroke, but further studies are needed on stroke. These findings should be considered in dietary guidelines.
REVIEW REGISTRATION
No review protocol registered.
Topics: Humans; Cardiovascular Diseases; Diet, Vegan; Prospective Studies; Myocardial Ischemia; Diet, Vegetarian; Vegetarians; Cohort Studies
PubMed: 36030329
DOI: 10.1007/s00394-022-02942-8 -
Nutrients Dec 2018Plant-based diets provide well-established physical and environmental health benefits. These benefits stem in part from the degree of restriction of animal-derived... (Review)
Review
Plant-based diets provide well-established physical and environmental health benefits. These benefits stem in part from the degree of restriction of animal-derived foods. Historically, meat and other animal-derived proteins have been viewed as an integral component of athletes' diets, leading some to question the adequacy of vegetarian or vegan diets for supporting athletic performance. The purpose of this review is to examine the impact of plant-based diets on human physical health, environmental sustainability, and exercise performance capacity. Based on currently available literature, it is unlikely that plant-based diets provide advantages, but do not suffer from disadvantages, compared to omnivorous diets for strength, anaerobic, or aerobic exercise performance. However, plant-based diets typically reduce the risk of developing numerous chronic diseases over the lifespan and require fewer natural resources for production compared to meat-containing diets. As such, plant-based diets appear to be viable options for adequately supporting athletic performance while concurrently contributing to overall physical and environmental health. Given the sparse literature comparing omnivore, vegetarian, and vegan athletes, particularly at the elite level, further research is warranted to ascertain differences that might appear at the highest levels of training and athletic performance.
Topics: Athletic Performance; Conservation of Natural Resources; Diet, Vegan; Diet, Vegetarian; Dietary Proteins; Environment; Exercise; Feeding Behavior; Humans; Vegetarians
PubMed: 30513704
DOI: 10.3390/nu10121841 -
Nutrients Dec 2021Health authorities increasingly recommend a more plant-based diet, rich in fruits, vegetables, pulses, whole grains and nuts, low in red meat and moderate in dairy,...
Health authorities increasingly recommend a more plant-based diet, rich in fruits, vegetables, pulses, whole grains and nuts, low in red meat and moderate in dairy, eggs, poultry and fish which will be beneficial for both health and the environment. A systematic review of observational and intervention studies published between 2000 and January 2020 was conducted to assess nutrient intake and status in adult populations consuming plant-based diets (mainly vegetarian and vegan) with that of meat-eaters. Mean intake of nutrients were calculated and benchmarked to dietary reference values. For micronutrient status, mean concentrations of biomarkers were calculated and compared across diet groups. A total of 141 studies were included, mostly from Europe, South/East Asia, and North America. Protein intake was lower in people following plant-based diets compared to meat-eaters, but well within recommended intake levels. While fiber, polyunsaturated fatty acids (PUFA), folate, vitamin C, E and magnesium intake was higher, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake was lower in vegetarians and vegans as compared to meat-eaters. Intake and status of vitamin B12, vitamin D, iron, zinc, iodine, calcium and bone turnover markers were generally lower in plant-based dietary patterns compared to meat-eaters. Vegans had the lowest vitamin B12, calcium and iodine intake, and also lower iodine status and lower bone mineral density. Meat-eaters were at risk of inadequate intakes of fiber, PUFA, α-linolenic acid (ALA), folate, vitamin D, E, calcium and magnesium. There were nutrient inadequacies across all dietary patterns, including vegan, vegetarian and meat-based diets. As plant-based diets are generally better for health and the environment, public health strategies should facilitate the transition to a balanced diet with more diverse nutrient-dense plant foods through consumer education, food fortification and possibly supplementation.
Topics: Adult; Aged; Aged, 80 and over; Animals; Asia; Diet, Vegan; Diet, Vegetarian; Dietary Fiber; Dietary Proteins; Eating; Energy Intake; Europe; Feeding Behavior; Female; Humans; Male; Meat; Micronutrients; Middle Aged; North America; Nutrients; Nutritional Status; Vitamins
PubMed: 35010904
DOI: 10.3390/nu14010029 -
International Journal of Molecular... Nov 2022There is evidence indicating that a vegan diet could be beneficial in the prevention of neurodegenerative disorders, including Alzheimer's disease (AD). The purpose of... (Review)
Review
There is evidence indicating that a vegan diet could be beneficial in the prevention of neurodegenerative disorders, including Alzheimer's disease (AD). The purpose of this review is to summarize the current knowledge on the positive and negative aspects of a vegan diet regarding the risk of AD. Regarding AD prevention, a vegan diet includes low levels of saturated fats and cholesterol, contributing to a healthy blood lipid profile. Furthermore, it is rich in phytonutrients, such as vitamins, antioxidants, and dietary fiber, that may help prevent cognitive decline. Moreover, a vegan diet contributes to the assumption of quercetin, a natural inhibitor of monoamine oxidase (MAO), which can contribute to maintaining mental health and reducing AD risk. Nonetheless, the data available do not allow an assessment of whether strict veganism is beneficial for AD prevention compared with vegetarianism or other diets. A vegan diet lacks specific vitamins and micronutrients and may result in nutritional deficiencies. Vegans not supplementing micronutrients are more prone to vitamin B12, vitamin D, and DHA deficiencies, which have been linked to AD. Thus, an evaluation of the net effect of a vegan diet on AD prevention and/or progression should be ascertained by taking into account all the positive and negative effects described here.
Topics: Humans; Diet, Vegan; Alzheimer Disease; Vegans; Diet, Vegetarian; Micronutrients; Vitamins; Diet
PubMed: 36499257
DOI: 10.3390/ijms232314924 -
The Proceedings of the Nutrition Society May 2022The concept of plant-based diets has become popular due to the purported benefits for both human health and environmental impact. Although 'plant-based' is sometimes... (Review)
Review
The concept of plant-based diets has become popular due to the purported benefits for both human health and environmental impact. Although 'plant-based' is sometimes used to indicate omnivorous diets with a relatively small component of animal foods, here we take it to mean either vegetarian (plant-based plus dairy products and/or eggs) or vegan (100% plant-based). Important characteristics of plant-based diets which would be expected to be beneficial for long-term health are low intakes of saturated fat and high intakes of dietary fibre, whereas potentially deleterious characteristics are the risk of low intakes of some micronutrients such as vitamin B, vitamin D, calcium and iodine, particularly in vegans. Vegetarians and vegans typically have lower BMI, serum LDL cholesterol and blood pressure than comparable regular meat-eaters, as well as lower bone mineral density. Vegetarians in the EPIC-Oxford study have a relatively low risk of IHD, diabetes, diverticular disease, kidney stones, cataracts and possibly some cancers, but a relatively high risk of stroke (principally haemorrhagic stroke) and bone fractures, in comparison with meat-eaters. Vegans in EPIC-Oxford have a lower risk of diabetes, diverticular disease and cataracts and a higher risk of fractures, but there are insufficient data for other conditions to draw conclusions. Overall, the health of people following plant-based diets appears to be generally good, with advantages but also some risks, and the extent to which the risks may be mitigated by optimal food choices, fortification and supplementation is not yet known.
Topics: Animals; Cataract; Diet; Diet, Vegan; Diet, Vegetarian; Diverticular Diseases; Humans
PubMed: 35934687
DOI: 10.1017/S0029665121003748 -
JAMA Network Open Nov 2020Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these... (Randomized Controlled Trial)
Randomized Controlled Trial
Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial.
IMPORTANCE
Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions.
OBJECTIVE
To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults.
DESIGN, SETTING, AND PARTICIPANTS
This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone.
INTERVENTIONS
Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks.
MAIN OUTCOMES AND MEASURES
At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis.
RESULTS
Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (-1.3; 95% CI, -2.2 to -0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = -0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01).
CONCLUSIONS AND RELEVANCE
A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT02939638.
Topics: Absorptiometry, Photon; Adult; Aged; Blood Glucose; Body Composition; Body Weight; C-Peptide; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Diet, Fat-Restricted; Diet, Vegan; Energy Intake; Energy Metabolism; Female; Glycated Hemoglobin; Hepatocytes; Humans; Insulin; Insulin Resistance; Intra-Abdominal Fat; Lipid Metabolism; Liver; Male; Middle Aged; Muscle Fibers, Skeletal; Muscle, Skeletal; Obesity; Overweight; Postprandial Period; Proton Magnetic Resonance Spectroscopy; Triglycerides
PubMed: 33252690
DOI: 10.1001/jamanetworkopen.2020.25454 -
Nutrients Dec 2020Crohn's disease (CD) is a chronic, progressive, and destructive granulomatous inflammatory bowel disorder that can involve any part of the gastrointestinal tract. It has... (Review)
Review
Crohn's disease (CD) is a chronic, progressive, and destructive granulomatous inflammatory bowel disorder that can involve any part of the gastrointestinal tract. It has been presumed that different types of diet might improve gastrointestinal symptoms in CD patients. The aim of this review was to clarify the efficiency and indications of a low-"fermentable oligo-, di-, mono-saccharides and polyols" (FODMAP) diet (LFD) in CD and to further analyze the available data on other types of diets. PubMed, Cochrane Library, EMBASE and WILEY databases were screened for relevant publications regarding the effect of FODMAP diets on CD. Our search identified 12 articles analyzing the effect of an LFD in CD, 5 articles analyzing the effect of a Mediterranean diet (MD), 2 articles analyzing the effect of a vegetarian diet (VD), and 2 articles analyzing the effect of a low-lactose diet (LLD). The majority of the studies included in this review show the significant efficiency of the LFD in CD patients. We found significant evidence demonstrating that the LFD has a favorable impact on gastrointestinal symptoms in CD patients. Notwithstanding the evidence, it remains to be established if an LFD is more efficient than other types of diets in the short term and especially in the long term.
Topics: Crohn Disease; Databases, Factual; Diet; Diet, Carbohydrate-Restricted; Diet, Mediterranean; Diet, Vegan; Diet, Vegetarian; Fermentation; Gastrointestinal Diseases; Gastrointestinal Tract; Humans; Inflammatory Bowel Diseases; Nutrition Therapy; Polymers
PubMed: 33291329
DOI: 10.3390/nu12123751 -
Nutrients Jun 2022Gut microbiota plays a significant role in the maintenance of physiological homeostasis, contributing to human health. Nevertheless, some factors (sex, age, lifestyle,... (Review)
Review
Gut microbiota plays a significant role in the maintenance of physiological homeostasis, contributing to human health. Nevertheless, some factors (sex, age, lifestyle, physical activity, drug-based therapies, diet, etc.) affect its composition and functionality, linked to pathologies and immunological diseases. Concerning diet, it interacts with microorganisms, leading to beneficial or detrimental outcomes for the health of host. On the other hand, physical activity is known to be useful for preventing and, sometimes, treating several diseases of cardiovascular, neuroendocrine, respiratory, and muscular systems. This paper focuses on diet and physical activity presenting the current knowledge about how different diets (Western, ketogenic, vegan, gluten free, Mediterranean) as well as different types of exercise (intensive, endurance, aerobic) could shape gut microbiota.
Topics: Diet; Diet, Gluten-Free; Diet, Vegan; Exercise; Gastrointestinal Microbiome; Humans; Nutritional Status
PubMed: 35745186
DOI: 10.3390/nu14122456