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Context: The popularity of plant-based diets, characterized by a partial or complete exclusion of animal products, has increased significantly over the last 10 years. The exclusion of animal products removes the most common sources of vitamin B12, which can lead to vitamin B12 deficiency and result in irreversible damage, such as growth stunting., Objective: This aim of this systematic review and meta-analysis was to qualitatively evaluate all studies on this subject and to quantify the potential difference in vitamin B12 levels in healthy children and adolescents aged 5 to 18 years., Data Sources: PubMed and Embase databases were searched for relevant studies investigating vitamin B12 levels in healthy children and adolescents aged 5 to 18 years on plant-based diets., Data Extraction: Studies were assessed qualitatively with the AXIS tool and quantitatively with Stata 16.0 software., Data Analysis: Overall, children and adolescents on plant-based diets had a significantly lower vitamin B12 level than omnivorous children and adolescents (-97 pmol/L; 95%CI, -187 to -7; I2 = 98.5%), a difference that remained statistically significant after adjusting for methodological confounders. After subgroup analyses, this effect was not statistically significant for children and adolescents on vegetarian diets but remained significant in children and adolescents on vegan or macrobiotic diets. Moreover, total vitamin B12 intake nullified the mean difference in vitamin B12 levels., Conclusion: Despite high heterogeneity across studies, these results indicate that children and adolescents on plant-based diets, especially those on vegan and macrobiotic diets, may be at risk of developing vitamin B12 deficiency., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: An increased risk of age-related eye disease has been observed in individuals lacking a balanced diet. Following a plant-based diet may result in nutritional insufficiencies and negatively affect health if an effort is not made to ensure the consumption of fortified foods or specific supplements., Objective: The purpose of this article is to characterize the relationship between plant-based diets and age-related ocular outcomes among adults., Data Sources: A comprehensive literature review was performed using the MEDLINE, Embase, Cochrane, and PubMed databases up until December 19, 2021., Study Selection: Studies that focused on observed visual changes due to a reduced intake of animal products and that included a minimum of 50 eyes were eligible for inclusion., Data Extraction: Two levels of screening, quality assessment, and data extraction were conducted by 2 reviewers independently. The 21 studies identified from 814 unique studies progressed to data extraction and 15 were included in the quantitative analysis using STATA 15.0 fixed-effect and random-effect models computed on the basis of heterogeneity., Results: The 15 (n = 51 695 participants) assessed the impact of fish consumption, 8 studies (n = 28 753 participants) analyzed the effect of red meat intake, and 3 studies (n = 7723 participants) assessed the impact of omission of skim milk, poultry, and non-meat animal products and the presence of disease incidence as indicated by age-related macular degeneration or cataract development. Meta-analysis indicated regular consumption of fish (odds ratio [OR], 0.70; 95%CI, 0.62-0.79) and skim milk, poultry, and non-meat animal products (OR, 0.70; 95%CI, 0.61-0.79) reduced the risk of age-related eye disease development among adults. Consumption of red meat (OR, 1.41; 95%CI, 1.07-1.86) may increase the risk of age-related eye disease development., Conclusion: A pescatarian diet is associated with the most favorable visual outcomes among adults, whereas consumption of red meat negatively affects ocular health. Results suggest a need for more initiatives promoting a healthy and balanced diet., Systematic Review Registration: PROSPERO registration no. CRD42021269925., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: Depression is the most common causes of disease burden worldwide (GBD 2017 Disease and Injury Incidence and Prevalence Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet. 2018;392:1789-1858)., Objective: An umbrella review has been performed to assess the strength and validity of the available observational and trial evidence for the association between a variety of dietary patterns and depression., Data Sources: MEDLINE/PubMed, Scopus, Web of Science, EMBASE, PsycINFO, and Cochrane Database were searched., Data Extraction: The Joanna Briggs Institute Umbrella Review Methodology was used., Data Analysis: The review included 19 articles, covering a relatively wide range of dietary patterns: healthy dietary patterns (n = 8), Mediterranean diet (MedDiet) (n = 6), Dietary Inflammatory Index (DII) (n = 5), Western diet (n = 4), Dietary Approaches to Stop Hypertension (DASH) (n = 2), vegetarian diets (n = 4), and other dietary interventions (n = 2). The methodological quality of the included meta-analyses was generally low or critically low. The strength of the evidence was generally weak, although convincing or suggestive evidence was found for an inverse relationship between MedDiet/DII and depression. Higher adherence to the MedDiet and lower DII score were significantly associated with lower risk of depression., Conclusion: Considering the generally high heterogeneity and low quality of the available evidence, further studies adopting more coherent and uniform methodologies are needed., Systematic Review Registration: PROSPERO registration no. CRD42020223376., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Meta-inflammation is a chronic, low-grade state of inflammation secondary to cardiometabolic disorders related to overweight (OW), obesity (OB), consumption of poor nutritional and hypercaloric diets with excessive amounts of lipids and sugars. It can lead to severe metabolic and cardiovascular diseases. Several studies have reported that plant-based diets (PBDs) can be a useful non-pharmacological therapeutic tool for the prevention and treatment of meta-inflammation, since it has been reported that patients following PBDs have lower serum levels of proinflammatory markers, a reduction in weight, and an overall healthier lipid profile. In this review, we describe the pathophysiology of meta-inflammation, the growing worldwide trend toward adoption of PBDs, and how PBDs act to reduce meta-inflammation., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: Mental health may be influenced by some dietary patterns. Among common elements of beneficial patterns is high fruit and vegetable intake. However, no systematic review has been conducted to date, to our knowledge, that has assessed the influence of fruit and vegetable dietary patterns on a broad spectrum of mental health., Objective: We conducted a systematic review, using the PRISMA guidelines, of the observational studies analyzing the association between the dietary pattern of fruit and vegetables and the broad aspects of mental health in adult women., Data Sources: The databases PubMed and Web of Science were searched, and additional manual search for observational peer-reviewed studies was conducted for studies published until June 2019., Data Extraction: A total of 5911 studies were extracted and verified based on title and abstract for the inclusion criteria. All procedures were conducted independently by 2 researchers. The final number of included studies was 30. The review was structured around the type of observed outcome., Data Analysis: The included studies had defined habitual intake associated with dietary patterns with the intake of specific fruit and/or vegetables, and/or fruit or vegetable products (eg, juices), as well as any aspect of the broad spectrum of general mental health. The Newcastle-Ottawa Scale was used to assess bias. The observed association was not stated in all the included studies; some of them revealed a reverse relationship, but only for the vegetarian/vegan diet. A vegetarian diet may be characterized by high consumption of fruits and vegetables, but it sometimes may not be properly balanced, due to excluded products. This may be the reason of observed situation., Conclusions: A general positive influence was observed for the dietary patterns characterized by high consumption of fruit and vegetables and of fruit or vegetable products by women., Systematic Review Registration: PROSPERO registration no. CRD42019138148., (© The Author(s) 2021. Published by Oxford University Press on behalf of the International Life Sciences Institute.)

Context: Several epidemiological studies have investigated the association between a vegetarian diet and risk of depression, but because of inconsistency between studies, the exact association remains unclear., Objective: In this systematic review and meta-analysis, the relationship between vegetarian diets and risk of depression in observational studies was evaluated., Data Sources: The Medline, Embase, Scopus, ISI Web of Science, and Cochrane Library databases were searched from inception through September 1, 2020., Study Selection: Observational studies were included that examined mean levels of depression and risk for depression in vegetarians compared with nonvegetarians., Data Extraction: Pooled effect sizes were estimated using the random-effects model and were reported as standardized mean differences or odds ratios (ORs) with their corresponding 95%CIs. Heterogeneity was tested using the I2 statistic., Results: Combining 9 effect sizes in this meta-analysis illustrated that adherence to a vegetarian diet was associated with a 53% greater risk of depression compared with that of omnivores (95%CI, 1.14-2.07; I2 = 69.1%). Subgroup analysis of depression risk suggested that results depended on the type of vegetarian diet and country where the study was conducted. For studies that assessed a semivegetarian diet (OR, 1.86; 95%CI, 1.42-2.44; I2 = 35.7%) and those conducted in Europe and the United States (OR, 1.45; 95%CI, 1.06-1.98; I2 = 73.2%), there was a positive association between a vegetarian diet and depression, but in lacto-ovo vegetarians and Asian countries, a null association was found. Comparing mean depression scores showed no evidence of difference between vegetarians and nonvegetarians (n = 16; standardized mean difference, 0.10; 95%CI, -0.01 to 0.21; I2 = 79.1%)., Conclusion: Vegetarian diet significantly increased depression risk; however, the findings were not robust, and more studies are required to investigate the vegetarian diet and depression association., (© The Author(s) 2021. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: The numbers of vegans and vegetarians have increased in the last decades. However, the impact of these diets on bone health is still under debate., Objective: This systematic review and meta-analysis sought to study the impact of vegetarian and vegan diets on bone mineral density (BMD) and fracture risk., Data Sources: A systematic search was conducted of PubMed, Scopus, and Science Direct, covering the period from the respective start date of each database to November 2017., Data Extraction: Two investigators evaluated 275 studies against the inclusion criteria (original studies in humans, written in English or Spanish and including vegetarian or vegan diets and omnivorous diets as factors with BMD values for the whole body, lumbar spine, or femoral neck and/or the number of fractures as the outcome) and exclusion criteria (articles that did not include imaging or studies that included participants who had suffered a fracture before starting the vegetarian or vegan diet). The quality assessment tool for observational cohort and cross-sectional studies was used to assess the quality of the studies., Results: Twenty studies including 37 134 participants met the inclusion criteria. Compared with omnivores, vegetarians and vegans had lower BMD at the femoral neck and lumbar spine and vegans also had higher fracture rates., Conclusions: Vegetarian and vegan diets should be planned to avoid negative consequences on bone health., Systematic Review Registration: PROSPERO registration no. CRD42017055508.

Context: Although a recent meta-analysis of randomized controlled trials showed that adoption of a vegetarian diet reduces plasma lipids, the association between vegetarian diets and long-term effects on plasma lipids has not been subjected to meta-analysis., Objective: The aim was to conduct a systematic review and meta-analysis of observational studies and clinical trials that have examined associations between plant-based diets and plasma lipids., Data Sources: MEDLINE, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for articles published in English until June 2015., Study Selection: The literature was searched for controlled trials and observational studies that investigated the effects of at least 4 weeks of a vegetarian diet on plasma lipids., Data Extraction: Two reviewers independently extracted the study methodology and sample size, the baseline characteristics of the study population, and the concentrations and variance measures of plasma lipids. Mean differences in concentrations of plasma lipids between vegetarian and comparison diet groups were calculated. Data were pooled using a random-effects model., Results: Of the 8385 studies identified, 30 observational studies and 19 clinical trials met the inclusion criteria (N = 1484; mean age, 48.6 years). Consumption of vegetarian diets was associated with lower mean concentrations of total cholesterol (-29.2 and -12.5 mg/dL, P < 0.001), low-density lipoprotein cholesterol (-22.9 and -12.2 mg/dL, P < 0.001), and high-density lipoprotein cholesterol (-3.6 and -3.4 mg/dL, P < 0.001), compared with consumption of omnivorous diets in observational studies and clinical trials, respectively. Triglyceride differences were -6.5 (P = 0.092) in observational studies and 5.8 mg/dL (P = 0.090) in intervention trials., Conclusions: Plant-based diets are associated with decreased total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol, but not with decreased triglycerides., Systematic Review Registration: PROSPERO number CRD42015023783. Available at: https://www.crd.york.ac.uk/PROSPERO/display&#95;record.asp?ID=CRD42015023783., (© The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute.)

Vegetarian diets have been associated with a lower incidence of several chronic diseases. The benefits of plant-based diets are related mainly to the improvement of metabolic parameters that can indicate risk for such diseases. Some metabolic factors, such as oxidative balance, lipid profile, and glucose homeostasis, can be improved directly by diet, but paradoxically, some characteristics of vegetarian diets may promote a negative scenario that increases the risk of certain chronic diseases. Additionally, many benefits of a vegetarian diet are mediated by the gut microbiota, members of which not only have taxonomic and functional differences but also produce diverse, specific metabolites that vary according to whether the host consumes an omnivorous or a vegetarian diet. This review examines the modulation of human metabolism and gut microbiota by vegetarian and omnivorous dietary patterns and explores how this modulation may affect the risk of cardiovascular disease., (© The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Vegetarian and vegan diets offer significant benefits for diabetes management. In observational studies, individuals following vegetarian diets are about half as likely to develop diabetes, compared with non-vegetarians. In clinical trials in individuals with type 2 diabetes, low-fat vegan diets improve glycemic control to a greater extent than conventional diabetes diets. Although this effect is primarily attributable to greater weight loss, evidence also suggests that reduced intake of saturated fats and high-glycemic-index foods, increased intake of dietary fiber and vegetable protein, reduced intramyocellular lipid concentrations, and decreased iron stores mediate the influence of plant-based diets on glycemia. Vegetarian and vegan diets also improve plasma lipid concentrations and have been shown to reverse atherosclerosis progression. In clinical studies, the reported acceptability of vegetarian and vegan diets is comparable to other therapeutic regimens. The presently available literature indicates that vegetarian and vegan diets present potential advantages for the management of type 2 diabetes.

Prostate cancer is the most commonly diagnosed non-skin cancer in men in the United States. Among environmental factors, diet may play a particularly important role in its incidence, progression, and clinical outcome. This article reviews the findings of eight observational studies and 17 intervention or laboratory trials on the effect of plant-based diets and plant nutrients on both the progression and clinical outcome of prostate cancer as well as additional studies examining mechanisms that may explain dietary effects. While additional long-term therapeutic clinical trials are needed to further elucidate the role of diet, these early investigations suggest that a recommendation for individual patients to shift their diets toward plant foods may serve as an important component of the tertiary treatment of prostate cancer.

Nutrition is now becoming once more of intense interest to biological and medical scientists working on the control of development and human health. It is also now of ever greater public health interest. Few scientists, however, recognize that the same interest for those involved in fundamental science and public health developed a century ago focusing on the way in which nutrition and specific micronutrients, as well as general energy and protein intakes, were crucial to infant growth and appropriate development. The discovery of vitamins was matched by the proposition that stunted children in poor communities in the Western world were suffering from poverty-related poor diets. The critical role of nutrition was established by feeding studies, which then led to major food and agricultural policy changes during the Second World War, when food supplies were scarce throughout Europe. The success of these wartime policies led to a revolution in governmental thinking and a cheap food policy, together with a major boost in national agricultural production as an issue of national security. Nutritionists transferred their scientific interest to the study of childhood malnutrition in the developing world. The promotion of intensive agriculture and the food industry led to a revolution in food supplies, with the intense promotion of meat, milk, butter, and sugar production and consumption. The resulting escalation in cardiovascular disease related to the dietary change slowly altered public health policies, but as cardiovascular deaths decreased in the developed world, obesity and diabetes progressively increased. Now the lower- and middle-income countries (i.e., the developing world) have far more cardiovascular disease as Western diets and cultural habits are imported. The remarkable escalation of diabetes and cardiovascular disease, particularly in populations currently and previously subjected to malnutrition, now reveals unusual susceptibility to these diseases. This susceptibility is increasingly related to the conjunction of fetal malnutrition and later inappropriate diets. The alarming escalation in the health burden suggests that two-thirds of the world's population is super-sensitive to weight gain, diabetes, cardiovascular disease, and perhaps many cancers. New evidence on epigenetics and the structural changes in the fetus in response to inappropriate maternal diets provides mechanisms to explain this. Unfortunately, a vicious intergenerational cycle of maternal and fetal epigenetic change seems to herald markedly increased future burdens of disease. The nutrition field is therefore challenged not only in terms of science, but also in new dimensions of public health of immense economic significance.

The increasing global health problems of overweight and obesity are associated with coronary heart disease, hypertension, diabetes, osteoarthritis, and certain cancers, among other health concerns. Vegetarian diets are associated with reduced body weight, lower incidence of certain chronic disease, and lower medical costs compared with non-vegetarian diets. We reviewed the literature to ascertain the extent to which and by what mechanism(s) a plant-based diet may mediate body weight.

Hypertension affects approximately 50 million individuals in the United States and approximately 1 billion worldwide. Although heredity plays a role in blood pressure variability, diet and lifestyle exert considerable influence in blood pressure regulation. This report reviews the evidence of the relationship between a vegetarian diet and blood pressure regulation and presents data as to the putative mechanisms of action.

Vegetarian diets based on soy-protein appeared to be effective in treating the hyperlipidemia of nephrotic syndrome. Whether there is a unique effect of soy or whether all very low-fat, low-saturated-fat, low-cholesterol, and low-protein diets have similar effects remains unknown.