Vegetarian Diet Research Articles

The role of vegetarian diet in Nephrolithiasis

Nephrolithiasis, commonly known as kidney stone disease, is a prevalent condition with significant morbidity worldwide. Notably, this medical condition is strongly influenced by nutritional habits. Dietary choices play a critical role in both the formation and prevention of kidney stones, highlighting the importance of proper nutrition in managing this disease. This review explores the impact of a vegetarian diet on nephrolithiasis. Evidence suggest that plant-based diets, which excludes animal protein, may contribute to a reduced risk of kidney stone formation. Vegetarian diet could be also considered as higher in fruits and vegetables, so in conclusion, people on plant-based diet have a water-rich food intake. Not only the fluid intake, but also the balance of calcium and oxalates is very important in managing risk of forming kidney stones. This diet typically result in lower acid load, higher urinary pH and increased urinary citrate levels. Everything mentioned is a key preventive strategy against kidney calculi. Nephrolithiasis has undenyable colligation with diet. Patients dietary choices and their lifestyle could strongly influence the course of this disease. Overall, well-planned vegetarian diet may offer protective benefits against nephrolithiasis. It should be individualized and preferably prepared by a professional dietitian. In this case, it is important to remember that our diet plays role similarly in genesis as in recurrence of kidney stone disease. Changing eating habits aims to reduce lithogenic risk factors.

Unveiling the effects of exercise and protein diet on pancreatic structure in ovariectomized aged rats

Objective: Evaluate structural alterations of the pancreas in ovariectomized elderly female rats that ingested different animal or vegetable protein sources and who underwent moderate resistance exercise. Methods: Female Wistar rats were divided into eight experimental groups: sedentary and non-ovariectomized animals plus vegetable protein diet (CVS) or animal protein diet (CAS); trained and non-ovariectomized rats plus vegetable protein diet (CVT) or animal protein diet (CAT); sedentary and ovariectomized groups plus vegetable protein diet (VOS) or animal protein diet (AOS); trained and ovariectomized animals plus vegetable protein diet (VOT) or animal protein diet (AOT). Results: Our results showed a decrease in pancreatic islet area in sedentary groups submitted to ovariectomy. On the other hand, we observed an increased frequency of minor and medium pancreatic islets in vegetable and animal diets, respectively. Additionally, all groups had a significant difference in volume density of acini, ducts, blood vessels, and pancreatic islets. Finally, immunohistochemistry demonstrated a decrease of glucagon in sedentary ovariectomized groups and a decrease of insulin in ovariectomized groups submitted to resistance training. Conclusion: Both resistance training and dietary intake contributed to pancreatic modifications in estrogen-deprived groups. Accordingly, further studies are needed regarding the structural and functional properties involving both interventions and menopause for a better understanding of our results.

Dietary recommendations of the Moroccan Society of Rheumatology (SMR) for patients with ostéosarcopenia.

The objective of this study was to develop the first Moroccan recommendations concerning nutrition in patients with osteosarcopenia. A steering committee consisting of rheumatologists and nutritionists drafted the initial version of the recommendations in light of the literature review and the recommendations of international societies. The draft was reviewed by a reading committee of 13 experts to approve the final version. Four overarching principles and ten recommendations were established. The overarching principles emphasize that nutritional advice is not a substitute for the pharmacological treatment of osteosarcopenia. Instead, it should be based on scientific evidence and take into account the specific characteristics of Moroccan society. The recommendations emphasize the significance of adequate calcium and vitamin D intake while evaluating the benefit-risk ratio in instances where calcium supplementation is indicated. A balanced intake of trace elements, vitamins, proteins, and dairy products should be maintained. The Mediterranean diet is recommended, while vegetarian diets and restrictive diets in individuals who are not overweight are not advised. It is recommended that individuals who fast during Ramadan consume a varied and balanced diet. It is recommended that the consumption of soft drinks and alcohol be limited. The consumption of phytoestrogens from food in moderation is considered beneficial as part of a balanced diet. Nevertheless, the use of supplements is not advised. The purpose of this work is to provide Moroccan rheumatologists with a practical tool to improve the nutritional aspect in patients with osteosarcopenia.

Culturally Tailored Lifestyle Modification Strategies for Hypertension Management: A Narrative Review.

Hypertension (HTN) is a significant global health challenge affecting billions of individuals worldwide. The prevalence of HTN varies considerably across the globe due to diverse factors, such as lifestyle influenced by culture, genetics, health care access, and socioeconomic conditions. Lifestyle modification has a substantial impact on blood pressure management; however, some cultural practices and behaviors affect recommended lifestyle modification strategies for HTN management. The purpose of this review was to explore lifestyle modification strategies for HTN management from a cultural perspective. Lifestyle modification, including physical activity, stress reduction, changes in dietary patterns (adopting a low-sodium diet and intake of fruit and vegetables), and weight management, provide an effective non-pharmacologic intervention for the management of hypertension. Individual's cultural practices have the potential to determine their diet, physical activity levels, knowledge, and perception about HTN, adherence to treatment and medications, and the use of local herbal preparations for HTN management. Culture focuses on individuals' belief, practices and how these beliefs and practices influence their lifestyle behaviors for HTN management. It is important to consider patients' cultural beliefs before recommending lifestyle behaviors for HTN management.

Effective weed control through post-emergence herbicides to enhance blackgram (Vigna mungo L.) productivity in South India

Pulses are essential components of vegetarian diet and play a pivotal role in addressing malnutrition by providing a vital source of dietary protein. However, weed competition remains as a significant obstacle to blackgram (Vigna mungo L) production, resulting in 25 to 35% yield losses. A field experiment was carried out at the National Pulses Research Centre, Tamil Nadu Agricultural University, Vamban, Pudukkottai, India during Kharif seasons of 2020 and 2021, to assess the suitable post-emergence herbicides for appropriate weed control in blackgram grown under irrigated conditions. The experimental field was observed to contain notable grass weed flora, specifically Dactyloctenium aegyptium and Chloris barbata, as well as broadleaved weeds, such as Flaveria australica, Cleome gynandra, Eclipta alba, Convolvulus arvensis, Digera arvensis, Vicia spp., and Celosia argentea. The results demonstrated that among the chemical weed management methods, spraying of Fomesafen @ 220 g + Fluzifop p-butyl @ 220 g ha−1 at 20 days after sowing (DAS) as a post-emergence herbicide treatment exhibited superior weed control efficiency, recording 66.80% and 68.53% at 30 and 45 DAS, respectively and recorded higher seed yield of 1088 kg ha−1. Additionally, this method generated 8.1% higher net income and 12.5% more benefit–cost ratio than hand weeding, making it an economically profitable strategy for maximizing blackgram yield and effective labour management.

Vegetarian Diet Reduced Gastroesophageal Reflux Disease in a Nationwide Longitudinal Survey in Taiwan.

This large, longitudinal follow-up cohort study aimed to explore how being a vegetarian and related factors impacted the incident gastroesophageal reflux disease (GERD) in a comprehensive Taiwanese cohort. The study cohort was enrolled from the Taiwan Biobank. Vegetarian status, duration of being a vegetarian, type of vegetarian diet, and whether or not the participants had GERD were recorded from self-reported surveys. Associations between vegetarian status, duration, and type of diet with incident GERD were analyzed with multivariate logistic regression with adjustments for confounding variables. After excluding participants with pre-existing GERD, we included 23,714 participants into the study. Multivariable analysis showed that vegetarian status (current vs. never; hazard ratio [HR], 0.697; 95% confidence interval [CI], 0.546 to 0.889; p = 0.004) was significantly inversely associated with incident GERD; conversely, ever being a vegetarian was not associated (p = 0.489). In addition, those who had been a vegetarian for 6 years or more had 0.72 times lower risk of GERD compared to those who had never been a vegetarian (HR, 0.717; 95% CI 0.558 to 0.922, p = 0.009). No significant differences were observed regarding the type of vegetarian diet with incident GERD. The results showed that following a vegetarian diet was an independent protective factor for incident GERD, with a significant protective effect observed in those who adhered to a vegetarian diet for at least 6 years. Future research is warranted to explore the underlying mechanisms and whether adopting a vegetarian diet can decrease the incidence of GERD.

Wegetarianizm nad Wisłą w literaturze przełomu XIX i XX wieku

The article is devoted to the reception of vegetarianism in Polish literature at the turn of the 19th and 20th centuries. The study recalls the most important popular science publications raising the issues of the vegetarian diet (including the works of Moes-Oskragiełło, Drzewiecki, Jankowski and Jastrzębowski), which are confronted with the literary images of vegetarians (in the works of Reymont, Weyssenhoff, Rodziewiczówna and Mazanowski). The subject of vegetarianism and vegetarians presented in Polish prose evolved over the first decades of the 20th century. Initially, it was identified mainly with a type of diet, and its followers were the elderly, often marginalized by society. Combining vegetarianism with the ethical issue regarding killing of animals can be seen in Rodziewiczówna and Mazanowski’s novels. In literary images of vegetarians, we will also find echoes of popular science publications about a vegetarian diet that has been emerging since the 1890s.

Exploring the Possibilities of Incorporating Edible Insects into a Vegetarian Diet: A Survey of Vegetarian Consumer Acceptance.

Due to environmental, health, and ethical concerns, more consumers are reducing their meat consumption or giving it up entirely. Plant protein is most often chosen as a sustainable source of protein. Still, recently, edible insects have been gaining popularity as a source of alternative protein with a better nutritional profile. However, there is no information on whether vegetarians can accept insects. An online survey was conducted with a sample of 790 vegetarians to address this gap. The findings of this survey are crucial in understanding the potential acceptance of insects in vegetarian diets. We found that 13% of the respondents approve of using processed insect protein in vegetarian dishes. Moreover, 9% of the respondents declared that they had knowingly consumed insects before; of these, 42% of them found the taste of the insects to be neutral, 16% found it to be very good, and 25% found it to be good. The level of insect acceptance was influenced by the type of vegetarian diet and its duration of use. Furthermore, pesca-vegetarians and flexi-vegetarians were the most likely to eat insects for ecological reasons (x¯ = 3.54 ± 0.74; x¯ = 3.00 ± 0.67, respectively). These findings do not eliminate the possibility of using edible insects in vegetarian diets but support their partial acceptance.

Quantitative analysis of fat distribution in men and women: contribution of diet, physical activity, and FTO genotype

BACKGROUND: The Russian Federation is among the top ten countries in terms of obesity prevalence among adults. AIM: To identify the endogenous (biological factors such as age and FTO genotype) and exogenous (diet and physical activity level) factors that influence body fat accumulation and distribution among a group of women and men from Moscow. MATERIAL AND METHODS: A total of 464 volunteers, consisting of 231 women and 233 men aged between 18 and 60 years, from Moscow took part in a single-center, cross-sectional, observational study. The program involved measuring body height, weight, body and limb girths, as well as conducting caliperometry, bioimpedance analysis, and administering questionnaires. Indices of body fat distribution were calculated. Additionally, differences in genotype, specifically the rs9939609 TA variant in the FTO gene, were also determined. RESULTS: Maintaining a vegetarian diet for at least three years was associated with lower fat and fat-free mass, but not with abdominal fat in both men and women. Engaging in regular physical activity had the most significant impact on abdominal fat in both genders. Furthermore, participating in amateur or professional sports activities for a minimum of 180 minutes per week was associated with lower overall body fat. We found no association between the FTO rs9939609 gene and fat accumulation or distribution, regardless of diet and physical activity levels. CONCLUSION: The results suggest that vegetarian diet and regular physical activity are likely to be the most effective total and abdominal fat loss strategy for male and female adult residents of Moscow.

Vitamin D intake and status in children and adolescents: Comparing vegetarian, vegan, and omnivorous diets.

This study aimed to evaluate papers analysing dietary intake, 25-hydroxyvitamin D (25(OH)D) concentrations and anthropometry in children on vegetarian, vegan and omnivorous diets, as research indicates all diets generally fall below recommended vitamin D intake. This mini review examined the vitamin D status of children aged 1-18 years by systematically searching PubMed, Google Scholar and Scopus databases from January 1, 2000, to December 31, 2023. The review included nine studies published between 2000 and 2023. Four studies reported lower vitamin D intake in children on vegetarian and vegan diets compared to omnivores. Three studies reported lower 25(OH)D concentrations in children on vegetarian and vegan diets. Specifically, one study found lower concentrations in vegans compared to omnivores, another found lower concentrations in vegetarians and vegans not taking supplements and a third reported lower 25(OH)D concentrations in Asian children aged 3-4.5 years compared to Caucasian children. Three studies found no significant differences in 25(OH)D between diet groups. Three studies assessing anthropometry showed that vegetarians have similar body weight and height as omnivores. Children across all dietary groups may have low vitamin D intakes; supplementation should be considered for those with inadequate sun exposure, especially those avoiding animal products.

Sustainable Dietary Patterns and Alternative Food Sources

Sustainable nutrition ensures optimal dietary intake by evaluating the life cycle of foods and their environmental impacts, aiming to meet current needs without jeopardizing the ability of future generations to do the same. It is characterized by low greenhouse gas emissions, minimal water footprint, efficient energy and land use, and reduced food waste. Sustainable dietary models, which have become increasingly important in the face of rising food demand and climate change challenges, include the Mediterranean Diet, Nordic Diet, DASH Diet, Double Pyramid Model, Flexitarian Diet, EAT-Lancet Commission Reference Diet, and Vegetarian and Vegan diets. Alternative protein sources such as algae, insects, and cultured meat are also significant. Algae offer sustainability through ocean use but have unclear metabolic impacts. Insects are efficient and environmentally friendly but require safety assessments. Cultured meat promises environmental benefits but faces cost and acceptance hurdles. Promoting sustainable eating habits requires a collective effort and is a shared responsibility towards our planet and ourselves.

Determination of the Consumer Profile in Relation to New Food Products Based on Soy with Microalgae in Brazil

ABSTRACT Due to demand for functional foods and the increase of individuals adopting a vegetarian diet, the objective of this work was to investigate the preferences and consumption of soy products with microalgae among the Brazilian population. Employing an online questionnaire, participants reported consumption habits of meat and soy-based products with microalgae. The findings revealed that 74% of respondents did not have the habit of consuming soy. The majority had never consumed products with microalgae; however, those who had, reported good experiences, which indicates that the development of products with microalgae should be encouraged and explored.

A First Step Towards Black Soldier Fly Larvae (Diptera: Stratiomyidae) Welfare by Considering Dietary Regimes (Part I).

The insect farming sector is expanding, but knowledge of insect welfare is still limited. This article aims to optimize the dietary regime for "black soldier fly" (Hermetia illucens L., BSF) larvae by applying a holistic view of welfare. Four diets were tested: control (CONTR, commercial laying hen feed), vegetable (VEG), omnivorous (OMN), and carnivorous (MEAT) diet, conducting experiments at a large (2000 larvae) and small scale (100 larvae). Rearing parameters were calculated including the growth rate, substrate reduction, efficiency of conversion of digested food, waste reduction index, and survival rate. Chemical analyses were conducted on BSF larvae and the residual frass. While the MEAT diet appears to be non-well-performing for the larvae, the VEG diet performed comparably to the control diet. Interestingly, the OMN diet demonstrated improved efficiency when evaluating the growth process at both scales. The chemical composition of larvae and frass highlighted the nutritional adequacy of the OMN diet, with the BSF larvae showing adequate protein and lipid content without nutrient catabolism or signs of discomfort. Applying the five freedoms of Brambell's report as a welfare standard for animal rearing and evaluating performance as an indirect indicator of welfare, the OMN diet appears to promote larval welfare in rearing practices.

Dietary vegetable Sarcochlamys pulcherrima Gaud. And its bioactive compound myricitrin promotes white adipose browning in obese models via AMPK/SIRT1/UCP1 upregulation

Obesity, a worldwide epidemic, is a metabolic disturbance marked by acute adipose inflammation in the body due to accumulation of surplus nutrients. The aim of the study is to inverse the pathological development of obesity through conversion of WAT to brown AT by employing the traditionally acclaimed fat reducing efficacy of Sarcochlamys pulcherrima Gaud. (SP), a leafy dietary vegetable, and its isolated bioactive compound Myricitrin (MR). The study was carried out using 3T3-L1 adipocytes and HF diet C57BL/6 mice treated with SPEF (SP enriched fraction) and MR. Accumulation of triglycerides, lipids and ROS were checked along with mitochondrial biogenesis. Immunoblotting for AMPK dependent mitochondrial biogenesis, browning markers, lipogenic and inflammatory proteins were checked aided by in silico analysis. Histopathological analysis of the adipose tissue was supported with immunoblotting techniques. Treatment with MR significantly reduced the triglyceride, lipid and ROS levels with elevated mitochondrial biogenesis. MR also upregulates AMPK/SIRT1 dependent browning markers: UCP1 and PRDM16 and reduces pro-inflammatory cytokines with reduced lipogenesis. Administration of SPEF 150 and 300 mg/kg b.w for 6 weeks on HF diet mice showed significant reduction in body weight, triglyceride and cholesterol levels. Histology of adipose tissue showed brown AT depots in the treated group. In silico analysis showed the activation of SIRT1 substrate with MR leading to changes in adipose tissue morphology. The overall WAT browning efficacy of S. pulcherrima and its isolated bioactive compound MR was demonstrated in the present study. Further scientific substantiations can be carried out for the development of nature-based anti-obesogenic drugs.

Effects of a Vegetarian Diet on the Development of Thyroid Disorders.

This study aims to explore the impact of different types of vegetarian diets on thyroid health, particularly focusing on the prevalence of thyroid disorders. Vegetarianism has had increasing popularity and has been particularly prominent in Asia, where a large proportion of the population has adopted a vegetarian diet, whereas in North America, the prevalence of vegetarianism remains very small. Vegetarian and vegan diets have been known to pose a risk of deficiencies in minerals and vitamins including vitamin B12, selenium, vitamin A, iron, and iodine, which are crucial for thyroid health. Studies have shown that deficiencies in the aforementioned minerals and vitamins can exacerbate both hyper- and hypothyroidism. This study reviews global cohort studies and highlights the need for a balanced diet with appropriate supplementation of crucial minerals and vitamins involved in thyroid hormone synthesis and further amplifies the need for continued studies and modifications in recommendations to incorporate vegetarian diets as an important confounding factor in the development of thyroid disease.

Community screening for iron deficiency in reproductive aged women: Lessons learnt from Australia.

Reproductive-aged women are at an increased risk of developing iron deficiency (ID). We aimed to develop a non-invasive screening tool to identify ID in women and assess the acceptability of screening. We screened women (age 18-49 years) in the community of Western Australia. acceptability of screening, assessed by the feasibility of recruiting the required sample size (n = 323). Hand grip strength, finger prick haemoglobin concentration (Hb), prevalence of heavy menstrual bleeding (HMB), diet, pregnancy history, blood donation, symptoms of ID and history of ID or anaemia (Hb < 120 g/L). Those with Hb <130 g/L and no history of iron therapy in the past 2 years were given referrals for venous full blood count and ferritin sampling. Across 5 days, we recruited 640 eligible women. Of which, 178 (28%) had HMB and 79 (12%) were anaemic. Mean age was 33.5 ± 9.2 years, and mean Hb was 132.4 ± 11.9 g/L. In the past 2 years: 335 (52%) were diagnosed with ID or anaemia; 322 (50%) had taken oral iron; and 210 (33%) had an intravenous iron infusion. Vegetarian diets were followed by 89 (14%); 40 (6%) were regular blood donors; 290 (45%) had a previous pregnancy. HMB increased the risk of symptoms of ID and having prior ID/anaemia diagnosis (67% vs. 47%) or treatment (p < 0.022). Hand grip strength showed a positive relationship with both Hb (adjusted R2 = 0.012, p = 0.004) and ferritin (adjusted R2 = 0.135, p = 0.005). ID screening was well accepted by women in the community, with high recruitment rates over a short period. Future screening tool development may consider incorporating hand grip strength and HMB assessment.

Characteristics of Hospitalized Patients With and Without Celiac Disease on a Gluten-Free Diet.

Most people maintaining a gluten-free diet (GFD) do not have celiac disease (CD). Comorbidities and associated conditions in this population are largely unknown. This study identified demographics, dietary patterns, and diagnoses for patients prescribed a GFD during hospitalization and compared patients with CD to those without CD. We performed a retrospective cross-sectional study for hospital admissions with a GFD between Jan 1, 2010 and June 30, 2022, while excluding patients missing demographic data (n = 113). We compared patients with and without a CD diagnosis, including multivariable logistic regression to identify characteristics independently associated with a CD diagnosis. We analyzed 1527 hospitalized patients of all ages. A minority (n = 467, 30.6%) carried a CD diagnosis. Age, sex, body mass index, and Medicare/Medicaid enrollment and additional diagnoses associated with a GFD (e.g., IBS) were not significantly different. The CD cohort was more predominantly white (66.6% vs 58.4%, p = 0.007) and non-Hispanic (62.5% vs. 52.7%, p = 0.001). While hospitalized, patients with CD had fewer additional dietary restrictions (mean 0.33 vs 0.56, p < 0.001) and more frequent micronutrient supplementation (26.6% vs 21.4%, p = 0.03). CD was independently associated with malnutrition (OR 1.86, 95% CI 1.31-2.65) and inversely associated with a vegetarian diet (OR 0.35, 95% CI 0.15-0.81), reduced lactose diet (OR 0.25, 95% CI 0.13-0.50), and Hispanic ethnicity (OR 0.56, 95% CI 0.35-0.90) while controlling for other covariates. Two-thirds of hospitalized patients receiving a GFD do not have a diagnosis of CD. Among GFD inpatients, CD is associated with fewer dietary restrictions and independently associated with malnutrition.

Plant-Based Beverages: Consumption Habits, Perception and Knowledge on a Sample of Portuguese Citizens.

Plant-based beverages (PBB) consumption has increased significantly worldwide due to an interest in vegetarian/vegan diets, taste preferences, health and ethical and environmental issues. Therefore, this study intends to investigate consumption habits, consumer preferences and consumers' level of knowledge about PBB. In this study, a voluntary, anonymous questionnaire survey was applied to a sample of participants from Portugal. The sample was recruited by convenience, and therefore, the distribution among the groups was not even. Data analysis involved different statistical techniques: basic statistics, chi-square tests, factor analysis, cluster analysis and tree classification analysis. The results indicated that the most consumed PBB were almond, soy and oat beverages. The majority of consumers chose these beverages for nutritional and health reasons, while a smaller number consumed them as part of a vegetarian or vegan diet. The main motivations for consuming PBB are mainly associated with sustainability and health benefits. The results regarding the respondents' knowledge about PBB revealed that a health-related profession was the most significant predictor. These results allowed us to conclude that the factors of nutrition, health, ethics and practice of a vegetarian/vegan diet influence the consumption of PBB. It was also concluded that being in a healthcare profession, along with age and professional status within this field, were significant factors influencing the level of knowledge about PBB.

Vegetarian diet and pregnancy outcome

ObjectiveVegetarian diets are becoming increasingly popular. Our aim was to evaluate the association of a vegetarian diet with pregnancy, labor, and newborn’s outcome. Study designThis retrospective case-control study included 150 women on a vegetarian diet and 300 omnivores. The data were collected from Tampere University Hospital pregnancy database from January 2015 to April 2021. Diet was a self-reported variable. Outcomes of interest were compared between the groups. The frequency of small-for-gestational age (SGA) newborns and low birth weight were primary outcomes. Other parameters concerning pregnancy, labor, and newborn served as secondary outcomes. ResultsThe rate of SGA at the 10 % cutoff was lower in the vegetarian group. Based on a definition of two standard deviations, SGA did not differ between the vegetarian diet group and the control group. The median birthweight was significantly higher in the vegetarian group. Gestational diabetes (GDM) was more common in the vegetarian group, however the numbers of large for gestational age (LGA) newborns were comparable between the study groups. Labor induction was more common, and the second stage of labor was longer in the vegetarian group. Preterm births (< 32+0 and < 37+0 gestational weeks) were more common in the control group. No differences were found in the mean umbilical artery pH value, 1- and 5- minutes Apgar scores or the number of newborns transferred to the neonatal intensive care unit and neonatal ward. The proportions of hypertensive disorders in pregnancy did not differ between the groups. ConclusionAccording to our results, a vegetarian diet may be considered safe during pregnancy. It was not associated with an increased risk of pregnancy- or neonatal complications.

A systematic review and meta-analysis of functional vitamin B12 status among adult vegans.

The dietary intake of vitamin B12 among unsupplemented vegans is notably lower compared to both vegetarians and omnivores. Prolonged low intakes of vitamin B12, such as seen in those adhering to a vegan diet, lead to physiological deficiency of vitamin B12 and an elevated risk of B12-related morbidity. However, while serum B12 serves as a conventional biomarker for assessing B12 status, its utility is limited given its sensitivity and specificity in ascribing physiological deficiency of B12 and the functional vitamin B12 status of those adhering to vegan diets is unclear. We conducted a systematic review and meta-analysis using data based on the full panel of biomarkers of vitamin B12 status to test whether adherence to a vegan diet is associated with an elevated risk of functional vitamin B12 deficiency compared to vegetarian or omnivorous diets. In addition, subgroup analysis was carried out to look at the effect of vitamin B12 supplement use on B12 status among vegans. Our search identified 4002 records, of which 19 studies met the inclusion criteria for the systematic review and 17 studies were taken forward for the meta-analysis. Meta-analysis results revealed significantly lower serum B12, pmol/ (-0.72 [-1.26, -0.18]; p = 0.01) and elevated total homocysteine, μmol/L (tHcy) (0.57 [0.26, 0.89]; p < 0.001) concentrations, alongside elevated methylmalonic acid, nmol/L (MMA) (0.28 [-0.01, 0.57]; p = 0.06) and lower holotranscobalamin, pmol/ (HoloTC) (-0.42 [-0.91, 0.07]; p = 0.09) levels among vegan adults compared to omnivores, indicating increased functional B12 deficiency in addition to low vitamin B12 status in vegan adults. There were no differences between vegans and vegetarians in HoloTC (0.04 [-0.28, 0.35]; p = 0.814) or MMA (-0.05 [-0.29, 0.20]; p = 0.708), but differences were found in serum B12 (-0.25 [-0.40, -0.10]; p = 0.001) and for tHcy (0.24 [0.09, 0.39]; p = 0.002) concentrations. Subgroup analyses indicated that the use of vitamin B12 supplements among vegans contributes to significant improvements in all biomarker concentrations compared to their unsupplemented counterparts. Our findings underscore the need for improved strategies to redress poor vitamin B12 status with appropriate B12 supplementation use among those adhering to vegetarian and vegan diets.