Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study

A comparative analysis of nutritional quality, amino acid profile, and nutritional supplementations in plant-based products and their animal-based counterparts in the UK

Plant-based (PB) food products have surged in popularity over the past decade. Available PB products in the UK market were extracted from NielsenIQ Brandbank and compared with animal-based (AB) counterparts in their nutrient contents and calculated Nutri-Scores. The amino acid contents of four beef products and their PB alternatives were analysed by LC-MS/MS. PB products consistently exhibited significantly higher fibre content across all food groups. Protein was significantly higher in AB products from all food groups except beef and ready meals. PB products were more likely to have higher Nutri-Scores compared to AB counterparts, albeit with greater score variability within each food group. Nutrient fortifications were primarily focused on dairy and ready meals; the most supplemented nutrient was vitamin B12 (found in 15% of all products). A higher proportion of EAAs in relation to total protein content was observed in all beef products.

A Healthful Plant-Based Diet as an Alternative Dietary Approach in the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease

Plant-based diets (PBDs) are gaining attention as a sustainable and health-conscious alternative for managing various chronic conditions, including metabolic dysfunction-associated steatotic liver disease (MASLD). In the absence of pharmacological treatments, exploring the potential of lifestyle modifications to improve biochemical and pathological outcomes becomes crucial. The adoption of PBDs has demonstrated beneficial effects such as weight control, increased metabolic health and improved coexisting diseases. Nonetheless, challenges persist, including adherence difficulties, ensuring nutritional adequacy, and addressing potential deficiencies. The aim of this review is to provide a comprehensive overview of the impact of PBDs on MASLD, emphasizing the need for tailored dietary interventions with professional support to optimize their effectiveness in preventing and treating metabolic diseases.

A Case Report and Literature Review on Dietary Practices and Megaloblastic Anemia in a Young Female: Unraveling the Impact of Nutrition on Hematological Health

Megaloblastic anemia, stemming from vitamin B12 or folate deficiencies, poses diagnostic challenges due to its diverse clinical presentation. We report a case of a 25-year-old female college student presenting with symptoms indicative of megaloblastic anemia, attributed to her recent adoption of a strict vegetarian and vegan diet. Clinical manifestations included dizziness, palpitations, blurred vision, vertigo, headaches, burning sensations, excessive sweating, mouth ulcers, and unintentional weight loss. Physical examination revealed pale palpebral conjunctiva and sweating on the palms and soles. Laboratory findings confirmed megaloblastic anemia secondary to vitamin B12 deficiency, with elevated mean corpuscular volume (MCV), reticulocyte count, serum methylmalonic acid (MMA), and homocysteine levels. Treatment with intramuscular cyanocobalamin injections and oral vitamin B12 supplementation led to symptomatic improvement and normalization of hematological parameters. This case underscores the crucial role of dietary habits in hematological health. Vegetarian and vegan diets, devoid of animal products rich in vitamin B12, increase the risk of deficiency. Early recognition and management of such deficiencies are imperative to prevent long-term complications. A literature review corroborates the association between vegetarianism/veganism and megaloblastic anemia risk. Healthcare providers should vigilantly assess dietary histories, particularly in patients with hematological abnormalities. Further research is warranted to explore strategies for optimizing nutrient intake in individuals adhering to vegetarian or vegan diets, aiming to mitigate the risk of nutritional deficiencies and associated complications.

Impact of Prevalent Dietary Pattern on Serum Vitamin B12 Status and Its Association With Inflammation Among Reproductive Age Women

SCOPE

Association between vitamin B12 deficiency (VB12D) and dietary patterns being well documented has bearing on obstetrics and neonatal outcomes. However, relationship between VB12D and serum inflammatory markers (IMs), particularly in vegetarian diet and Polycystic ovary syndrome (PCOS), remains elusive. This cross-sectional study assesses VB12D and IMs among reproductive age women consuming different diets.

METHODS AND RESULTS

Nonvegetarian (PCOS, n = 104; healthy, n = 148) and vegetarian women (PCOS n = 112; healthy, n = 186) are for evaluated clinical, biochemical, hormonal assessment, inflammatory, and four vitamin B 12 (VB12) markers. VB12D is defined by Fedosov's wellness quotient (4cB12). Using 4cB12, prevalence of VB12D is discerned in 54.4% (PCOS: 72.1%; healthy 36.5%) and 93.4% (PCOS: 95.9%; healthy: 91.9%) among nonvegetarians and vegetarians, respectively. Vegetarian PCOS women depict lowest median (interquartile range [IQR]) of serum B12 76.2(72.6) pg mL-1, holotranscobalamine (HTC) 37.9(11.3) and highest homocysteine (HCY) 40.32(6.0) µmol L-1, methylmalonic acid (MMA) 352.26(156.7) nmol L-1 with highest Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and IMs (Monocyte chemoattractant protein 1 (MCP-1), High sensitivity C-reactive protein (hs-CRP), Tumour Necrosis Factor alpha (TNF-α) and Interleukin 6 (IL-6)). Significant correlation of serum hs-CRP, TNF-α, and IL-6 with VB12 markers is observed.

CONCLUSION

The VB12D is rampant among reproductive age women that gets exacerbated by PCOS or vegetarian diet. It is directly correlated with magnitude of proinflammatory markers. The results carry substantial implications for public health policies aimed at improving preconception maternal VB12 status for better future pregnancy and offspring outcomes.

A comparison of the nutritional content and price between dairy and non-dairy milks and cheeses in UK supermarkets: A cross sectional analysis

Background: Non-Dairy (ND) food consumption is rapidly increasing in the UK and for many consumers plant-based diets are presumed to be healthier than standard diets. ND alternatives have different nutritional compositions, and their consumption could present challenges on a public-health level. Aim: To compare the price and nutritional composition of dairy and ND milks and cheeses in UK supermarkets. Methods: Macro and micronutrient data was recorded from Alpro's website and the 6 leading UK grocers for their own-label ND milks and cheeses. For missing micronutrient values the McCance & Widdowson's dataset was used. 99 total products were extracted: 57 ND milks, 7 dairy milks, 10 dairy cheeses and 25 ND cheeses. Dairy milk and cheese were used as control against which all ND products were compared. Results: Soya and coconut milks had lower values of carbohydrates, sugars, calcium, iodine, and potassium (p < 0.01) than dairy. Almond milk had lower values of carbohydrates (p = 0.01), sugars, calcium, iodine, and potassium (p < 0.01) compared to dairy milk. Protein was significantly (p < 0.01) lower for all ND except soya. Dairy cheeses had higher values for energy, protein, iodine, potassium, riboflavin, vitamin B12 and calcium (p < 0.01) than ND. Median prices were similar between dairy and ND milks, whereas ND cheeses were significantly more expensive compared to dairy (p < 0.01). Conclusions: ND alternatives fall short in several key nutrients compared to dairy. Fortification, accurate labelling and nutrition education are needed to help consumers make healthy and informed choices.

Navigating the B vitamins: Dietary diversity, microbial synthesis, and human health

B vitamins are intricately involved in various physiological processes vital for health. Their significance is complicated by the heterogeneous landscape of B vitamin distribution in diets and the contributions of the gut microbiota. Here, we delve into the impact of these factors on B vitamins and introduce strategies, with a focus on microbiota-based therapeutic options, to enhance their availability for improved well-being. Additionally, we provide an ecological and evolutionary perspective on the importance of B vitamins to human-microbiota interactions. In the dynamic realms of nutrition and microbiome science, these essential micronutrients continue to play a fundamental role in our understanding of disease development.

An examination of relationships between vitamin B12 status and functional measures of peripheral neuropathy in young adult vegetarians

Introduction

Prevalence rates for vitamin B12 deficiency in U.S. adult vegetarians may exceed 30%, which is concerning given the role for this vitamin in numerous nervous system functions, including the synthesis of myelin sheaths. Defective myelin synthesis and repair are directly linked to peripheral neuropathy; yet, few investigations have examined how physical indicators of peripheral neuropathy (e.g., hand dexterity, vibration sensitivity and balance) are impacted in individuals adhering to vegetarian diets. This feasibility research explored the relationships between peripheral neuropathy and vitamin B12 status using a cross-sectional study design. In addition, a small pilot trial was conducted for limited-efficacy testing of vitamin B12 supplementation for reducing peripheral neuropathy.

Methods

Healthy, able-bodied adults (n = 38; 19-40 years of age) reported exclusive adherence to a vegetarian or vegan diet for 3 years. Peripheral neuropathy was measured using a force plate for assessing balance, and a vibration sensitivity tester and pegboard tests to assess hand dexterity. Serum vitamin B12 and folate were measured using standard radioimmunoassay techniques.

Results

Twenty-six percent of the sample displayed deficient or marginal vitamin B12 status (serum vitamin B12 <221 pmol/L). Participants with adequate vitamin B12 status scored 10% higher on the Purdue pegboard assembly test and 20% higher on the left hand adjusted functional dexterity test in comparison to participants with marginal-to-deficient vitamin B12 status (p < 0.05).

Discussion

These data provide preliminary evidence that peripheral neuropathy can be detected in individuals with marginal-to-deficient vitamin B12 status.

Vitamin B12 insufficiency and deficiency: a review of nondisease risk factors

Vitamin B12 deficiency and insufficiency can lead to both hematological and neurological impairments. This review examines nondisease causes and risk factors associated with dietary availability, such as eating habits, food processing, cooking techniques, and bioavailability, as well as increased physiological needs and iatrogenic factors linked to medication use or surgical procedures. As a result of these nondisease influences, groups at higher risk include vegans, vegetarians, older adults, individuals with limited diets, breastfed and preterm infants, and those who primarily consume foods prepared or cooked in ways that reduce vitamin B12 content, as well as individuals on certain medications or who have undergone specific surgeries. Recognizing these diverse risk factors helps develop strategies for prevention and intervention to minimize the adverse health effects related to B12 deficiency and insufficiency.

Micronutrient status of New Zealand adolescent women consuming vegetarian and non-vegetarian diets

BACKGROUND AND OBJECTIVES

Globally, there appears to be an ever-increasing interest in adopting a vegetarian diet. However, there are concerns that avoiding meat may increase the risk of anaemia and micronutrient deficiencies, especially for vulnerable populations, such as adolescent women. The objective of this study was to compare the micronutrient status of vegetarian and non-vegetarian adolescent women in New Zealand.

METHODS AND STUDY DESIGN

Adolescent women aged 15-18 y were recruited from eight locations across New Zealand. Blood samples were analysed for: haemoglobin, serum ferritin, soluble transferrin receptor, zinc, selenium, retinol binding protein, folate, vitamin B-12, vitamin D and parathyroid hormone.

RESULTS

Of the 182 participants who provided a blood sample, 15% self-identified as vegetarian (n=27). On average, vegetarians had 3.1% (95% CI -5.8 to -0.4, p=0.025) lower haemoglobin, and 8.3% (95%CI -14.1 to -2.1, p=0.004) lower selenium. In contrast, serum folate was 80.5% (95% CI 45.7 to 123.7, p<0.001) higher. The prevalence of zinc and selenium deficiency was higher among vegetarians (50% and 12%, respectively) than non-vegetarians (21%, and 2%, respectively).

CONCLUSIONS

Adolescent vegetarian women may be at increased risk of deficiency of micronutrients commonly found in animal products, including zinc and selenium, and may benefit from following dietary practices that enhance micronutrient intake and absorption.

Adoption of a Short-Term (4-Week) Vegan Diet as Part of 'Veganuary' Significantly Reduces Saturated Fatty Acid (SFA), Cholesterol, B12, and Iodine Intake in Omnivorous Individuals-An Observational Study

Global veganism campaigns like 'Veganuary' have gained popularity. We conducted an observational study to assess the impact of a 4-week vegan diet during 'Veganuary' on nutrient intake, status, knowledge, and motivations for veganism. Data were collected before and after 'Veganuary', using Food Frequency Questionnaires (FFQs) to estimate dietary intake. Micronutrient knowledge and motivation were assessed through questionnaires. A total of 154 UK adults aged 18-60 years (2019: n81; 2020: n73) participated. Groups were vegetarians and omnivores committed to a 4-week vegan diet during 'Veganuary'. Control groups were vegans and omnivores who did not transition. Short-term vegan diets significantly decreased intake of iodine, B12, cholesterol, and saturated fatty acids (SFAs) in omnivores. Micronutrient knowledge was low, and motivation for veganism varied. Short-term vegan diets reduce macro- and micronutrient intake in omnivores. Veganuary participants could benefit from nutritional guidance or supplementation. Attention is required for UK micronutrient intake and knowledge. Motivations for vegan pledges may influence diets, warranting further research.

Exploring Benefits and Barriers of Plant-Based Diets: Health, Environmental Impact, Food Accessibility and Acceptability

Unhealthy dietary patterns are directly linked to the current Global Syndemic consisting of non-communicable diseases, undernutrition and climate change. The dietary shift towards healthier and more sustainable plant-based diets is essential. However, plant-based diets have wide intra differences; varying from vegan diets that totally exclude meat and animal products to traditional ones such as the Mediterranean diet and the new Nordic diet. It is acknowledged that plant-based diets may contribute simultaneously to improving population health as well as to decreasing the environmental impact of food systems. Evidence from cohort and randomized-controlled trials suggests that plant-based dietary patterns have beneficial effects on bodyweight control, cardiovascular health and diabetes prevention and treatment. On the other hand, micronutrient requirements may not be met, if some plant-based diets are not well-planned. Additionally, studies showed that lower consumption of meat and animal products results in lower environmental impacts. Consequently, plant-based diets could be a key factor to increase diet sustainability. This narrative review addresses the advantages of adherence to plant-based diets on human and planetary health considering strains and barriers to achieve this dietary transition, including cultural acceptability and affordability factors. Finally, potential intervention and policy recommendations are proposed, focusing on the update of current national food-based dietary guidelines.

Vegan Diets for Children: A Narrative Review of Position Papers Published by Relevant Associations

The scientific discourse on vegan diets for children and adolescents primarily involves referencing position statement papers from different scientific and professional organizations, including paediatric associations. Over the past two decades, specialized associations have issued official statements and published position papers about adopting well-designed vegan diets during crucial life stages, including pregnancy and lactation, infancy, and childhood. A subset of these associations firmly supports the notion that a well-designed vegan diet can indeed be healthy and support normal growth and development during particularly delicate life stages, emphasizing careful planning, vitamin B12 supplementation, and regular supervised medical and dietetics oversight. In contrast, specific paediatric associations caution against vegan diets for children and adolescents, citing potential harm and the lack of adequate substantiation. These criticisms in position papers frequently point to lower-quality studies and/or outdated studies. Additionally, concerns extend to comparing vegan and omnivorous diets, considering public health issues such as obesity and early stages of cardiovascular disease as well as the risk of prediabetes and type 2 diabetes. Notably, some scepticism stems from studies where children's adherence to a well-designed vegan diet is incomplete. Scientific rigor suggests performing a comparable assessment of omnivorous and vegan diets. This narrative review highlights the need for a comprehensive, up-to-date literature review to inform balanced perspectives on vegan diets for children and adolescents. Researchers and decision-makers should aim to actively improve the design and consistent implementation of both diet types.

Veganism and body weight: An N of 1 self-experiment

The causal effect that veganism has on body weight has not been scientifically examined. An N of 1 self-experiment was conducted in which blinded body weight and additional behavioural and psychological measures were assessed during two phases of vegan vs. non-vegan lifestyle adherence. In study phase 1, body weight change was -0.8 kg over 1 month of veganism (vs. +0.5 kg non-vegan month). In study phase 2, weight change was -1.2 kg over two veganism months (vs. +1.6 kg non-vegan months). Behavioural and psychological measures were similar during vegan vs. non-vegan periods. Veganism appeared to reduce body weight in this N of 1 self-experiment.

Vegetarian Diet for Cardiovascular Disease Risk Reduction: Cons

Numerous studies have reported that adopting a plant-based diet can significantly reduce the risk of cardiovascular diseases (CVDs). Not only does a vegetarian diet help mitigate the risk of these diseases, but it also contributes to enhancing environmental sustainability. However, it is not necessary to universally recommend a vegetarian diet as a preventive measure against CVDs. More research is needed to determine whether completely excluding animal products is necessary, or if adhering to a predominantly plant-based diet is sufficient. In this opinion paper, the potential adverse health effects of a vegetarian diet and the barriers associated with adopting it will be discussed, in order to provide a rationale for the disadvantages of using a vegetarian diet for CVD risk reduction.

Nutritional Considerations for the Vegan Athlete

Accepting a continued rise in the prevalence of vegan-type diets in the general population is also likely to occur in athletic populations, it is of importance to assess the potential impact on athletic performance, adaptation, and recovery. Nutritional consideration for the athlete requires optimization of energy, macronutrient, and micronutrient intakes, and potentially the judicious selection of dietary supplements, all specified to meet the individual athlete's training and performance goals. The purpose of this review is to assess whether adopting a vegan diet is likely to impinge on such optimal nutrition and, where so, consider evidence based yet practical and pragmatic nutritional recommendations. Current evidence does not support that a vegan-type diet will enhance performance, adaptation, or recovery in athletes, but equally suggests that an athlete can follow a (more) vegan diet without detriment. A clear caveat, however, is that vegan diets consumed spontaneously may induce suboptimal intakes of key nutrients, most notably quantity and/or quality of dietary protein and specific micronutrients (eg, iron, calcium, vitamin B12, and vitamin D). As such, optimal vegan sports nutrition requires (more) careful consideration, evaluation, and planning. Individual/seasonal goals, training modalities, athlete type, and sensory/cultural/ethical preferences, among other factors, should all be considered when planning and adopting a vegan diet.

The association between vegetarian diet and varicose veins might be more prominent in men than in women

Background

Varicose veins (VVs), a common vascular disease is associated with a huge medical burden. The prevalence in women surpasses that in men. The role of vegetarian diets in the pathogenesis of the disease remains inconclusive. In this study, we examined the risk of VVs in vegetarian and non-vegetarian men and women.

Methods

The study involved 9905 adults whose data were obtained from Taiwan Biobank between 2008 and 2020. Information on VVs, sex, and vegetarian diets was obtained from participants' self-responses to the Taiwan Biobank questionnaires.

Results

The study subjects consisted of 4,142 men and 5,763 women. About 12% of men and 35% of women had VVs. Study participants were predominantly non-vegetarians (91.84% were men and 88.24% were women). Women had a higher risk of VVs than men. The odds ratio (OR); 95% confidence interval (CI) was 3.414; 2.995-3.891. There was a significant interaction between sex and vegetarian diets (p = 0.0034). Women were at higher risk of VVs than men both in the vegetarian (OR = 1.877, 95% CI = 1.270-2.774) and non-vegetarian (OR = 3.674, 95% CI = 3.197-4.223) groups. Based on vegetarian diets, only vegetarian men had a higher risk of VVs (OR = 1.453, 95% CI = 1.069 to 1.976). Based on the sex-stratified model, the risk of VVs was significantly higher in vegetarian men (OR = 1.457, 95% CI = 1.072-1.979), and in vegetarian and non-vegetarian women with corresponding ORs (95% CI) of 3.101 (2.528-3.803) and 3.599 (3.140-4.124), respectively.

Conclusion

Women were more susceptible to varicose veins compared to men, regardless of diet. However, in terms of diet, only men who followed a vegetarian diet were at greater risk for developing VVs.

Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults

BACKGROUND

It remains unclear whether non-animal-derived dietary protein sources (and therefore vegan diets) can support resistance training-induced skeletal muscle remodeling to the same extent as animal-derived protein sources.

METHODS

In Phase 1, 16 healthy young adults (m = 8, f = 8; age: 23 ± 1 y; BMI: 23 ± 1 kg/m²) completed a 3-d dietary intervention (high protein, 1.8 g·kg bm^-1·d^-1) where protein was derived from omnivorous (OMNI1; n = 8) or exclusively non-animal (VEG1; n = 8) sources, alongside daily unilateral leg resistance exercise. Resting and exercised daily myofibrillar protein synthesis (MyoPS) rates were assessed using deuterium oxide. In Phase 2, 22 healthy young adults (m = 11, f = 11; age: 24 ± 1 y; BMI: 23 ± 0 kg/m²) completed a 10 wk, high-volume (5 d/wk), progressive resistance exercise program while consuming an omnivorous (OMNI2; n = 12) or non-animal-derived (VEG2; n = 10) high-protein diet (∼2 g·kg bm^-1·d^-1). Muscle fiber cross-sectional area (CSA), whole-body lean mass (via DXA), thigh muscle volume (via MRI), muscle strength, and muscle function were determined pre, after 2 and 5 wk, and postintervention.

OBJECTIVES

To investigate whether a high-protein, mycoprotein-rich, non-animal-derived diet can support resistance training-induced skeletal muscle remodeling to the same extent as an isonitrogenous omnivorous diet.

RESULTS

Daily MyoPS rates were ∼12% higher in the exercised than in the rested leg (2.46 ± 0.27%·d^-1 compared with 2.20 ± 0.33%·d^-1 and 2.62 ± 0.56%·d^-1 compared with 2.36 ± 0.53%·d^-1 in OMNI1 and VEG1, respectively; P < 0.001) and not different between groups (P > 0.05). Resistance training increased lean mass in both groups by a similar magnitude (OMNI2 2.6 ± 1.1 kg, VEG2 3.1 ± 2.5 kg; P > 0.05). Likewise, training comparably increased thigh muscle volume (OMNI2 8.3 ± 3.6%, VEG2 8.3 ± 4.1%; P > 0.05), and muscle fiber CSA (OMNI2 33 ± 24%, VEG2 32 ± 48%; P > 0.05). Both groups increased strength (1 repetition maximum) of multiple muscle groups, to comparable degrees.

CONCLUSIONS

Omnivorous and vegan diets can support comparable rested and exercised daily MyoPS rates in healthy young adults consuming a high-protein diet. This translates to similar skeletal muscle adaptive responses during prolonged high-volume resistance training, irrespective of dietary protein provenance. This trial was registered at clinicaltrials.gov as NCT03572127.

Vegetarian and Vegan Diets: Beliefs and Attitudes of General Practitioners and Pediatricians in France

Studies suggest a decreasing trend in the consumption of meat products and a growing interest in vegetarian diets. Medical support may be relevant, especially when switching to a vegan diet. Our objective was to describe the beliefs and attitudes of primary care physicians toward vegetarian diets. A cross-sectional survey was conducted among general practitioners and pediatricians thorough a questionnaire including socio-demographic characteristics, specific care to vegetarians, and the risks and benefits of vegetarian diets according to physicians. Out of the 177 participating physicians, 104 (59%) have seen at least one vegetarian patient in consultation in the last three months. Half of the physicians declared that they would dissuade their patients from switching to a vegan diet (n = 88, 51%) and 14% (n = 24) from switching to an ovo-lacto-vegetarian (OLV) diet. Most physicians (n = 141, 88%) did not feel informed enough about these diets. Physicians thought that the most frequent deficiencies for OLV and vegan diets were iron (76% and 84%, respectively) and protein (45% and 79%, respectively). These results highlight the fact that French primary care physicians feel concerned by this subject and need more information on these diets. Specific recommendations would be useful to support their practice and relationship with vegetarians.

Plant-based diets and long-term health: findings from the EPIC-Oxford study

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 B12, 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.

Pancytopenia Due to Vitamin B12 and Folic Acid Deficiency-A Case Report

We report a case of severe pancytopenia in a 15-year-old patient due to a severe deficiency in vitamin B12 and folic acid, probably of nutritional origin. The clinical and biological course was favorable after vitamin supplementation. With this case, we discuss the diagnostic approach of pancytopenia with megaloblastic anemia in children and adolescents, as well as the mechanisms involved in vitamin B12 and B9 deficiency. Hypovitaminosis B12 is known in its severe form but its diagnosis is often made difficult by insidious signs and symptoms. Traditional intramuscular replacement therapy has now proven to be effective orally. The clinical manifestations of folic acid deficiency are relatively similar to those of vitamin B12 deficiency, reflecting their intricate co-enzymatic functions. Its supplementation is administered orally.

Dietary Patterns Are Associated With Multi-Dimensional Cognitive Functions Among Adults Aged 55 and Older in China

Background

The intake of certain food and nutrients may play a crucial role in cognitive health. However, research on the relationship between dietary patterns and cognitive function is limited. This study aims to investigate the associations between dietary patterns and multi-dimensional cognitive functions, such as global cognitive status and related domain profiles, mild cognitive impairment (MCI), and four major subtypes of Chinese adults.

Methods

Using the baseline data from the Community-based Cohort Study on Nervous System Diseases (2018–2019), we selected 4,309 Chinese adults aged 55 years and older as subjects with complete diet, cognition, and other related data. We collected food data for the past 12 months with a valid semi-quantitative food frequency questionnaire. Diving 49 food items into 13 subgroups, we used factor analysis to derive the main dietary patterns. We evaluated cognitive functions based on the scores of the Montreal Cognitive Assessment (MoCA) and used quantile regression and multivariable logistic regression to examine the relationship between dietary patterns and cognitive-related outcomes.

Results

We identified four dietary patterns, explaining 50.11% of the total variance: “meat-preferred” pattern, “plant-preferred” pattern, “eggs- and dairy-preferred” pattern, and “grain-preferred” pattern. After adjusting for all potential confounders, the “meat-preferred” pattern and the “plant-preferred” pattern were associated with higher scores of global cognition and several cognitive domains (p &lt;0.05), while the “grain-preferred” pattern was associated with lower scores of global cognition (β = −0.36, p &lt;0.05), execution (β = −0.19, p &lt;0.05), visuospatial (β = −0.09, p &lt;0.05), and language (β = −0.05, p &lt;0.05). Adults adhering to the “meat-preferred” pattern and the “plant-preferred” pattern had decreased odds of MCI and some MCI subtypes (p-trend &lt;0.05); in contrast, those in the top quartiles of the “grain-preferred” pattern had increased odds of MCI [adjusted odds ratio (AOR) = 1.34, 95% CI: 1.11–1.63, p-trend = 0.003].

Conclusions

Adhering to the “plant-preferred” pattern and the “meat-preferred” pattern may help improve the multi-dimensional cognitive functions; on the contrary, adhering to the “grain-preferred” pattern may worse cognitive health. More prospective studies in this field are needed to strengthen the evidence.

Mechanistic Link between Vitamin B12 and Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia in the elderly population, affecting over 55 million people worldwide. Histopathological hallmarks of this multifactorial disease are an increased plaque burden and tangles in the brains of affected individuals. Several lines of evidence indicate that B12 hypovitaminosis is linked to AD. In this review, the biochemical pathways involved in AD that are affected by vitamin B12, focusing on APP processing, Aβ fibrillization, Aβ-induced oxidative damage as well as tau hyperphosphorylation and tau aggregation, are summarized. Besides the mechanistic link, an overview of clinical studies utilizing vitamin B supplementation are given, and a potential link between diseases and medication resulting in a reduced vitamin B12 level and AD are discussed. Besides the disease-mediated B12 hypovitaminosis, the reduction in vitamin B12 levels caused by an increasing change in dietary preferences has been gaining in relevance. In particular, vegetarian and vegan diets are associated with vitamin B12 deficiency, and therefore might have potential implications for AD. In conclusion, our review emphasizes the important role of vitamin B12 in AD, which is particularly important, as even in industrialized countries a large proportion of the population might not be sufficiently supplied with vitamin B12.

Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review

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.

Adherence to the EAT-Lancet Diet and Risk of Stroke and Stroke Subtypes: A Cohort Study

BACKGROUND AND PURPOSE

We investigated the association between adherence to the EAT-Lancet diet, a sustainable and mostly plant-based diet, and risk of stroke and subtypes of stroke in a Danish population. For comparison, we also investigated the Alternate Healthy Eating Index-2010 (AHEI).

METHODS

We used the Danish Diet, Cancer and Health cohort (n=55 016) including adults aged 50 to 64 years at baseline (1993-1997). A food frequency questionnaire was used to assess dietary intake and group participants according to adherence to the diets. Stroke cases were identified using a national registry and subsequently validated by review of medical records (n=2253). Cox proportional hazards models were used to estimate hazard ratios and 95% CIs for associations with the EAT-Lancet diet or the AHEI and risk of stroke and stroke subtypes.

RESULTS

Adherence to the EAT-Lancet diet was associated with a lower risk of stroke, although not statistically significant (highest versus lowest adherence: hazard ratio, 0.91 [95% CI, 0.76-1.09]). A lower risk was observed for AHEI (0.75 [95% CI, 0.64-0.87]). For stroke subtypes, we found that adherence to the EAT-Lancet diet was associated with a lower risk of subarachnoid hemorrhage (0.30 [95% CI, 0.12-0.73]), and the AHEI was associated with a lower risk of ischemic stroke (0.76 [95% CI, 0.64-0.90]) and intracerebral hemorrhage (0.58 [95% CI, 0.36-0.93]).

CONCLUSIONS

Adherence to the EAT-Lancet diet in midlife was associated with a lower risk of subarachnoid stroke, and the AHEI was associated with a lower risk of total stroke, mainly ischemic stroke and intracerebral hemorrhage.

Replacing dietary animal-source proteins with plant-source proteins changes dietary intake and status of vitamins and minerals in healthy adults: a 12-week randomized controlled trial

PURPOSE

A shift towards more plant-based diets promotes both health and sustainability. However, controlled trials addressing the nutritional effects of replacing animal proteins with plant proteins are lacking. We examined the effects of partly replacing animal proteins with plant proteins on critical vitamin and mineral intake and statuses in healthy adults using a whole-diet approach.

METHODS

Volunteers aged 20-69 years (107 female, 29 male) were randomly allocated into one of three 12-week intervention groups with different dietary protein compositions: ANIMAL: 70% animal-source protein/30% plant-source protein; 50/50: 50% animal/50% plant; PLANT: 30% animal/70% plant; all with designed protein intake of 17 E%. We analysed vitamin B-12, iodine, iron, folate, and zinc intakes from 4-day food records, haemoglobin, ferritin, transferrin receptor, folate, and holotranscobalamin II from fasting blood samples, and iodine from 24-h urine.

RESULTS

At the end point, vitamin B-12 intake and status were lower in PLANT than in 50/50 or ANIMAL groups (P ≤ 0.007 for all). Vitamin B-12 intake was also lower in 50/50 than in ANIMAL (P < 0.001). Iodine intake and status were lower in both 50/50 and PLANT than in ANIMAL (P ≤ 0.002 for all). Iron and folate intakes were higher in PLANT than in ANIMAL (P < 0.001, P = 0.047), but no significant differences emerged in the respective biomarkers.

CONCLUSIONS

Partial replacement of animal protein foods with plant protein foods led to marked decreases in the intake and status of vitamin B-12 and iodine. No changes in iron status were seen. More attention needs to be paid to adequate micronutrient intakes when following flexitarian diets.

CLINICAL TRIAL REGISTRY

NCT03206827; registration date: 2017-06-30.

The Safe and Effective Use of Plant-Based Diets with Guidelines for Health Professionals

Plant-based diets, defined here as including both vegan and lacto-ovo-vegetarian diets, are growing in popularity throughout the Western world for various reasons, including concerns for human health and the health of the planet. Plant-based diets are more environmentally sustainable than meat-based diets and have a reduced environmental impact, including producing lower levels of greenhouse gas emissions. Dietary guidelines are normally formulated to enhance the health of society, reduce the risk of chronic diseases, and prevent nutritional deficiencies. We reviewed the scientific data on plant-based diets to summarize their preventative and therapeutic role in cardiovascular disease, cancer, diabetes, obesity, and osteoporosis. Consuming plant-based diets is safe and effective for all stages of the life cycle, from pregnancy and lactation, to childhood, to old age. Plant-based diets, which are high in fiber and polyphenolics, are also associated with a diverse gut microbiota, producing metabolites that have anti-inflammatory functions that may help manage disease processes. Concerns about the adequate intake of a number of nutrients, including vitamin B12, calcium, vitamin D, iron, zinc, and omega-3 fats, are discussed. The use of fortified foods and/or supplements as well as appropriate food choices are outlined for each nutrient. Finally, guidelines are suggested for health professionals working with clients consuming plant-based diets.

Role of Vitamin B12 and Folate in Metabolic Syndrome

Metabolic syndrome (MS) is a collection of pathological metabolic conditions that includes insulin resistance, central or abdominal obesity, dyslipidemia, and hypertension. It affects large populations worldwide, and its prevalence is rising exponentially. There is no specific mechanism that leads to the development of MS. Proposed hypotheses range from visceral adiposity being a key factor to an increase in very-low-density lipoprotein and fatty acid synthesis as the primary cause of MS. Numerous pharmaceutical therapies are widely available in the market for the treatment of the individual components of MS. The relationship between MS and vitamin B complex supplementation, specifically folic acid and vitamin B12, has been a subject of investigation worldwide, with several trials reporting a positive impact with vitamin supplementation on MS.

In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Vitamin B12,” “Folate,” “Metabolic Syndrome,” and “Insulin Resistance.” We explored the literature on MS for its epidemiology, pathophysiology, newer treatment options, with a special focus on the effectiveness of supplementation with vitamins B9 and B12.

According to the literature, vitamin B12 and folate supplementation, along with a host of novel therapies, has a considerable positive impact on MS. These findings must be kept in mind while designing newer treatment protocols in the future.

Targeting DNA Methylation in the Adult Brain through Diet

Metabolism and nutrition have a significant role in epigenetic modifications such as DNA methylation, which can influence gene expression. Recently, it has been suggested that bioactive nutrients and gut microbiota can alter DNA methylation in the central nervous system (CNS) through the gut-brain axis, playing a crucial role in modulating CNS functions and, finally, behavior. Here, we will focus on the effect of metabolic signals in shaping brain DNA methylation during adulthood. We will provide an overview of potential interactions among diet, gastrointestinal microbiome and epigenetic alterations on brain methylation and behavior. In addition, the impact of different diet challenges on cytosine methylation dynamics in the adult brain will be discussed. Finally, we will explore new ways to modulate DNA hydroxymethylation, which is particularly abundant in neural tissue, through diet.

Vegan vs. omnivore diets paradox: A whole-metagenomic approach for defining metabolic networks during the race in ultra-marathoners- a before and after study design

BACKGROUND

The effect of vegan diets on metabolic processes in the body is still controversial in ultra endurance athletes. The study aims to determine gut microbiome adaptation to extreme exercise according to vegan or omnivore diet consumed in ultra-marathoners. We also seek to evaluate long-term vegan diets' effects on redox homeostasis, and muscle fatigue, and assess energy availability.

METHODS

Seventy participants will be assigned to the study, including 35 vegan ultra-marathoners and 35 omnivores competing in the Sri-Chinmoy ultra marathon race. Research data will be collected from the participants at four steps (three visits to the research laboratory and the race day) throughout the study. At the first visit (seven days before the race), fecal samples, and anthropometric measurements will be collected. Body composition will be measured using DXA. Participants will be informed about keeping detailed food records and will be asked to record their diet data and activity logs during the entire study period. At second visit, maximum oxygen consumption will be measured on treadmill. On race day, blood samples will be collected immediately before, and 0. min, 2 hours, and 24 hours after the race. Body weight will be measured before and after the race. The blood and fecal samples will be stored at -80 C until analysis. Plasma malondialdehyde, reactive oxygen metabolites, total antioxidant capacity, Heatshockprotein-70, and serum Orosomucoid-1 will be analyzed in blood samples. Fecal samples will be analyzed with shotgun metagenomic analysis and interpreted using bioinformatics pipeline (HumanN2). Statistical tests will be analyzed using SPSS version 23.0 and R Software.

DISCUSSION

Study findings will determine the effects of the vegan diet on sports performance, revealing the multiple interactions between host and gut microbiome at the whole metagenomic level. Additionally, results will show the possible adaptation throughout the race by analyzing blood and fecal samples. Furthermore, by assessing energy availability and determining host-metabolite crosstalk for ultra-endurance athletes, possible nutritional deficiencies can be identified. Thus, advanced nutritional strategies can be developed based on metabolic needs.

TRIAL REGISTRATION

Current controlled trials, ISRCTN registry 69541705. Registered on 8 December 2019.

Association of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer: the Japan Public Health Center-based (JPHC) prospective study

Background

B vitamins and methionine are essential substrates in the one-carbon metabolism pathway involved in DNA synthesis and methylation. They may have essential roles in cancer development. We aimed to evaluate the associations of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer (EC) using data from the Japan Public Health Center-based Prospective Study.

Methods

We included 87,053 Japanese individuals who completed a food frequency questionnaire and were followed up from 1995–1998 to 2013 and 2015. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated by Cox proportional-hazard regression across quintiles of dietary intakes of B vitamins and methionine.

Results

After 1,456,678 person-years of follow-up, 427 EC cases were documented. The multivariable HR (95% CI) of incident EC in the highest versus lowest quintile of dietary intake of vitamin B12 was 1.75 (1.13–2.71; p-trend=0.01). Stratification analysis based on alcohol consumption showed that higher dietary intakes of vitamin B12 and methionine were associated with an increased risk of EC among never-drinkers; HRs (95% CIs) were 2.82 (1.18–6.74; p-trend=0.009; p-interaction=0.18) and 3.45 (1.32–9.06; p-trend=0.003; p-interaction 0.02) for vitamin B12 and methionine, respectively. Meanwhile, there was no association between vitamin B12 and methionine intake with the risk of EC among drinkers. There were no associations between dietary intake of folate or vitamin B6 and the risk of EC.

Conclusion

Dietary intake of vitamin B12 was positively associated with the risk of EC in the Japanese population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08721-8.

Unintended Consequences: Nutritional Impact and Potential Pitfalls of Switching from Animal- to Plant-Based Foods

Consumers are shifting towards plant-based diets, driven by both environmental and health reasons. This has led to the development of new plant-based meat alternatives (PBMAs) that are marketed as being sustainable and good for health. However, it remains unclear whether these novel PBMAs to replace animal foods carry the same established nutritional benefits as traditional plant-based diets based on pulses, legumes and vegetables. We modelled a reference omnivore diet using NHANES 2017–2018 data and compared it to diets that substituted animal products in the reference diet with either traditional or novel plant-based foods to create flexitarian, vegetarian and vegan diets matched for calories and macronutrients. With the exception of the traditional vegan diet, all diets with traditional plant-based substitutes met daily requirements for calcium, potassium, magnesium, phosphorus, zinc, iron and Vitamin B12 and were lower in saturated fat, sodium and sugar than the reference diet. Diets based on novel plant-based substitutes were below daily requirements for calcium, potassium, magnesium, zinc and Vitamin B12 and exceeded the reference diet for saturated fat, sodium and sugar. Much of the recent focus has been on protein quality and quantity, but our case study highlights the risk of unintentionally increasing undesirable nutrients while reducing the overall nutrient density of the diet when less healthy plant-based substitutes are selected. Opportunities exist for PBMA producers to enhance the nutrient profile and diversify the format of future plant-based foods that are marketed as healthy, sustainable alternatives to animal-based products.

Efficacy of supplementation with methylcobalamin and cyancobalamin in maintaining the level of serum holotranscobalamin in a group of plant-based diet (vegan) adults

Plant-based nutrition has become extremely popular in the contemporary era. Its positive effects are sustained by many studies, but one of its risks is that it is almost completely devoid of vitamin B12. In the present study, we analyzed the effects of two types of vitamin B12 supplements, cyancobalamin and methylcobalamin on the level of active serum vitamin (holotranscobalamin) in a group of Romanian individuals (n=42) following a (vegan) plant-based diet. The results revealed that cyancobalamin gives better results in maintaining B12, as quantified by the holotranscobalamin value (median=150 pcg/l) when compared with methylcobalamin (median=78.5 pcg/l). The frequency of administration, regardless of the quantity in one dose, is another important factor in maintaining the holotranscobalamin level within suitable limits. More frequent intakes give more optimal results. Vegans trying to supplement with alternative products (algae, kombucha, other fermented products), had the lowest levels of holotranscobalamin, always bellow the recommended level of 35 pcg/l (median=29 pcg/l). Vegans must be educated on B12 supplementation, about the pharmaceutical forms on the market and their performances and on choosing the optimal plan in order to avoid the onset of B12 deficiency.

Depression and Vegetarians: Association between Dietary Vitamin B6, B12 and Folate Intake and Global and Subcortical Brain Volumes

Deficiency of vitamin B6 and vitamin B12, mostly in vegetarians, is found to be associated with depression and adverse neurological function. We investigated whether vitamin B6, B12, and folate have an effect on brain structure, especially among depressed people who follow a specific diet. The study sample comprised 9426 participants from the UK Biobank cohort with a mean age of 62.4 years. A generalized linear model controlling for age, sex, body mass index, ethnicity, town send deprivation index, educational qualification, smoking, and alcohol intake was used to test the association between study groups and structural brain volumes. Depression was more prevalent, and intake of vitamin B6 and B12 was lower among vegetarians, while non-vegetarians had a lower intake of folate. Overall, no significant association was observed between vitamin B6, B12, and folate intakes and both global and subcortical brain volumes among participants with depression. However, vitamin B12 intake was positively associated with right pallidum among non-depressed participants, and a significant interaction between vitamin B12 intake and depression status on the right pallidum was observed. Also, a significant interaction between folate intake and depression status on grey matter (GM) volume and left thalamus was observed. Upon diet stratification, folate intake is associated with total brain volume and GM volume among vegetarians with depression. Furthermore, no significant associations were observed for subcortical regions. Our findings suggest that dietary intake of vitamin B6 and B12 might have an effect on brain structure. Vegetarians, particularly those who suffer from depression may benefit from supplementing their diets with vitamins B6, B12, and folate to ensure brain health. Further studies, especially with a larger sample size and longitudinal design, are needed to confirm these findings.

Nutrient status and growth in vegan children

Vegan diets have risen in popularity over the past 9 years. However, few studies have examined nutrient status and the effect of a vegan diet on the growth of children. This study analysed the existing literature on the health impact and growth impact of selected nutrients in vegan children. We assessed the intake of calories and protein, as well as the nutrients iron, calcium, vitamin D, cobalamin and folate. With a small percentage of outliers, vegan children showed normal growth and were less often obese. We found limited evidence that children on a vegan diet can obtain all the examined nutrients. Furthermore, as proper planning and supplementation by caregivers is needed, it is currently unknown how often vegan children follow well-planned diets. Deficiencies in cobalamin, calcium, and vitamin D seem to be the biggest risks associated with a poorly planned vegan diet. For a more definitive assessment, data on the intake and nutrient status of omega-3 fatty acids, zinc, iodine, and selenium in vegan children are needed. Future research should account for demographic shifts in those following a vegan diet, and should discriminate between vegan sub-populations that are open or closed towards scientific approaches, towards health in general, and toward supplementation. Studies should assess the modes and dosages of supplementation and the use of fortified foods or drinks, as well as adherence to the diet itself. Plant ferritin as a source of iron and endogenous cobalamin synthesis warrants further scientific inquiry. In summary, the current literature suggests that a well-planned vegan diet using supplementation is likely to provide the recommended amounts of critical nutrients to provide for normal progression of height and weight in children, and can be beneficial in some aspects. However, data on 5 critical nutrients are still missing, hampering a more definitive conclusion.

The impact of a vegan diet on pregnancy outcomes

OBJECTIVE

To determine the effect of a maternal vegan diet on pregnancy outcome.

STUDY DESIGN

This is a prospective observational study. Women with a singleton pregnancy who maintained the same diet prior to, and throughout current pregnancy were enrolled. Stratification was performed according to diet type: vegans, lacto-ovo-vegetarians, fish-eaters, and omnivores.

RESULTS

Overall, 273 women were enrolled, of them, 112 omnivores, 37 fish-eaters, 64 lacto-ovo-vegetarians, and 60 vegans. The vegan diet was significantly associated with an increased risk of small-for-gestational-age newborns compared only to an omnivore diet (RR = 5.9, 95% CI, 1.2-21.8). The incidence of preterm birth was similar in all groups. Vegans had lower birthweight compared to lacto-ovo-vegetarians (3015 ± 420 g vs. 3285 ± 482 g, P = 0.004), and to omnivores (3328 ± 495 g, P < 0.001), but not to fish-eaters. Vegans also had a lower mean gestational weight gain compared only to omnivores (11.6 ± 4.2 kg vs. 14.3 ± 4.6 kg, P = 0.001).

CONCLUSION

The vegan diet is associated with an increased risk for small-for-gestational-age newborns and lower birthweight.

Intake of vitamin B12 and other characteristics of women of reproductive age on a vegan diet in Australia

OBJECTIVE

(i) To examine demographic and health characteristics of women of reproductive age on a vegan diet in Australia and compare these to the general population; (ii) to identify sources and intake of vitamin B12 and compare intake to current recommendations and (iii) examine associations between participant characteristics and adequacy of vitamin B12 intake.

DESIGN

In this cross-sectional study, data were collected via an online survey. Demographic and health characteristics of women on a vegan diet were compared with women in the general population (using Australian Bureau of Statistics data). Intake of vitamin B12 was estimated using a FFQ and estimation of supplemental intake.

SETTING

Australia.

PARTICIPANTS

Participants (n 1530) were women aged 18-44 years who had been on a vegan diet for at least 6 months.

RESULTS

While BMI, smoking habits and intakes of fruit and vegetables compared favourably with the general population, 26 % of respondents had estimated intakes of vitamin B12 below recommendations. Analyses of relationships between vitamin B12 intake and participant characteristics revealed that the strongest predictor of intake was supplementation (P < 0·001); however, 25 % had not supplemented with vitamin B12 in the past 3 months.

CONCLUSIONS

The vitamin B12 intakes of a substantial proportion of Australian women of reproductive age consuming a vegan diet do not meet the recommended intake, which could adversely affect their health, and, if they are pregnant or lactating, that of their infants too. There is a need for further research in this area to identify effective strategies to address this situation.

A Systematic Review of the Association Between Vegan Diets and Risk of Cardiovascular Disease

BACKGROUND

Plant-based diets are gaining attention globally due to their environmental benefits and perceived health-protective role. A vegan diet may have cardiovascular benefits; however, evidence remains conflicting and insufficiently assessed.

OBJECTIVES

We evaluated the utility of the vegan diet in cardiovascular disease (CVD) prevention.

METHODS

We conducted a systematic review of studies evaluating the association between vegan diets and cardiovascular outcomes. We searched 5 databases (Ovid MEDLINE, EMBASE, Web of Science, Scopus, and OpenGrey) through 31 October 2020. Four investigators independently screened the full texts for inclusion, assessed quality, and extracted data from published reports.

RESULTS

Out of the 5729 identified records, 7 were included, comprising over 73,000 participants, of whom at least 7661 were vegans. Three studies, with at least 73,426 individuals (including at least 7380 vegans), examined risks of primary cardiovascular events (total CVD, coronary heart disease, acute myocardial infarction, total stroke, hemorrhagic stroke, and ischemic stroke) in individuals who followed a vegan diet compared to those who did not. None of the studies reported a significantly increased or decreased risk of any cardiovascular outcome. One study suggested that vegans were at greater risk of ischemic stroke compared to individuals who consumed animal products (HR, 1.54; 95% CI, 0.95-2.48). Yet in another study, vegans showed lower common carotid artery intima-media thickness (0.56 ± 0.1 mm vs. 0.74 ± 0.1 mm in controls; P < 0.001), and in 3 studies of recurrent CVD events, vegans had 0-52% lower rates. Furthermore, endothelial function did not differ between vegans and nonvegans. Using the Grading of Recommendations Assessment, Development and Evaluation approach, evidence was deemed to be of low to very low strength/quality.

CONCLUSIONS

Among the Western populations studied, evidence weakly demonstrates associations between vegan diets and risk of CVDs, with the direction of associations varying with the specific CVD outcome tested. However, more high-quality research on this topic is needed. This study was registered at PROSPERO as CRD42019146835.

Vegetarianism and veganism compared with mental health and cognitive outcomes: a systematic review and meta-analysis

CONTEXT

Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive impairment and mental health disorders have a high economic burden.

OBJECTIVE

A meta-analysis was conducted to examine the relationship between vegan or vegetarian diets and cognitive and mental health.

DATA SOURCES

PubMed, Scopus, ScienceDirect, and Proquest databases were examined from inception to July 2018.

STUDY SELECTION

Original observational or interventional human studies of vegan/vegetarian diets were selected independently by 2 authors.

DATA EXTRACTION

Raw means and standard deviations were used as continuous outcomes, while numbers of events were used as categorical outcomes.

RESULTS

Of 1249 publications identified, 13 were included, with 17 809 individuals in total. No significant association was found between diet and the continuous depression score, stress, well-being, or cognitive impairment. Vegans/vegetarians were at increased risk for depression (odds ratio = 2.142; 95%CI, 1.105-4.148) and had lower anxiety scores (mean difference = -0.847; 95%CI, -1.677 to -0.018). Heterogeneity was large, and thus subgroup analyses showed numerous differences.

CONCLUSIONS

Vegan or vegetarian diets were related to a higher risk of depression and lower anxiety scores, but no differences for other outcomes were found. Subgroup analyses of anxiety showed a higher risk of anxiety, mainly in participants under 26 years of age and in studies with a higher quality. More studies with better overall quality are needed to make clear positive or negative associations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42018097204.

High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores

BACKGROUND

Acute protein turnover studies suggest lower anabolic response after ingestion of plant vs. animal proteins. However, the effects of an exclusively plant-based protein diet on resistance training-induced adaptations are under investigation.

OBJECTIVE

To investigate the effects of dietary protein source [exclusively plant-based vs. mixed diet] on changes in muscle mass and strength in healthy young men undertaking resistance training.

METHODS

Nineteen young men who were habitual vegans (VEG 26 ± 5 years; 72.7 ± 7.1 kg, 22.9 ± 2.3 kg/m²) and nineteen young men who were omnivores (OMN 26 ± 4 years; 73.3 ± 7.8 kg, 23.6 ± 2.3 kg/m²) undertook a 12-week, twice weekly, supervised resistance training program. Habitual protein intake was assessed at baseline and adjusted to 1.6 g kg^-1 day^-1 via supplemental protein (soy for VEG or whey for OMN). Dietary intake was monitored every four weeks during the intervention. Leg lean mass, whole muscle, and muscle fiber cross-sectional area (CSA), as well as leg-press 1RM were assessed before (PRE) and after the intervention (POST).

RESULTS

Both groups showed significant (all p < 0.05) PRE-to-POST increases in leg lean mass (VEG: 1.2 ± 1.0 kg; OMN: 1.2 ± 0.8 kg), rectus femoris CSA (VEG: 1.0 ± 0.6 cm²; OMN: 0.9 ± 0.5 cm²), vastus lateralis CSA (VEG: 2.2 ± 1.1 cm²; OMN: 2.8 ± 1.0 cm²), vastus lateralis muscle fiber type I (VEG: 741 ± 323 µm²; OMN: 677 ± 617 µm²) and type II CSA (VEG: 921 ± 458 µm²; OMN: 844 ± 638 µm²), and leg-press 1RM (VEG: 97 ± 38 kg; OMN: 117 ± 35 kg), with no between-group differences for any of the variables (all p > 0.05).

CONCLUSION

A high-protein (~ 1.6 g kg^-1 day^-1), exclusively plant-based diet (plant-based whole foods + soy protein isolate supplementation) is not different than a protein-matched mixed diet (mixed whole foods + whey protein supplementation) in supporting muscle strength and mass accrual, suggesting that protein source does not affect resistance training-induced adaptations in untrained young men consuming adequate amounts of protein.

CLINICAL TRIAL REGISTRATION

NCT03907059. April 8, 2019. Retrospectively registered.

Dietary Quality in Vegetarian and Omnivorous Female Students in Germany: A Retrospective Study

Vegetarian diets have gained in popularity, especially among highly educated women, and are considered beneficial to health. Comparative studies assessing the diet of vegetarians against omnivores are rather limited and often provide ambivalent results. Therefore, this study examined the nutrient intake and nutritional quality of vegetarian and omnivorous diets in a group of 61 female students in Germany. Habitual dietary intake was evaluated using a validated graphical online food frequency questionnaire (FFQ). Differences in nutrient intakes were analyzed by Mann-Whitney-U-Tests. Odds Ratios (OR) were calculated for vegetarians exceeding dietary reference values (DRV) compared to omnivores. The overall nutritional quality was assessed using the Healthy-Eating-Index-2015 (HEI-2015). In omnivores, intakes of total energy from saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), long-chain omega-3 polyunsaturated fatty acids (LC-n3-PUFA), cholesterol, sucrose, lactose, retinol, and cobalamin were significantly higher than in vegetarians. Significantly lower intakes were observed for fiber, magnesium, and beta-carotene. Significant OR were detected for total fat (OR = 0.29), SFA (OR = 0.04), beta-carotene (OR = 4.55), and cobalamin (OR = 0.32). HEI-2015 scores were higher for vegetarians than for omnivores (79 points versus 74 points) and significant differences were recorded for the HEI-2015 components dairy, seafood & plant proteins, fatty acids, added sugars, and saturated fatty acids.

Vegetarian diets during pregnancy: effects on the mother's health. A systematic review

While interest in vegetarian nutrition has been steadily increasing, some aspects have not yet been consistently investigated. One topic requiring evidence-based confirmation is the adoption of a vegetarian diet during pregnancy and lactation. Maternal diet is not only correlated with the fetus's and infant's health, but appears relevant for that of the mother as well. Not only is an adequate delivery of nutrients to the fetus and infant mandatory, but the increased physiological needs of the maternal body require an adequate supply of nutrients and can represent harmful stress events that may lead to well-defined pathological conditions. In this review, we aim to systematically investigate state-of-the-art of vegetarian diets during pregnancy and lactation, focusing on maternal nutritional status and pregnancy outcomes. Data are scarce, often inconsistent and not homogeneous for many of the topics we considered, mainly because only a few studies have been performed in developed countries, whereas other studies have derived from developing countries, where vegetarianism can be a proxy indicator of malnutrition. For this reason, we did not find sufficient data to provide evidence-based information and recommendations. To date, the available literature does not clearly support a negative impact on the mother's health and pregnancy outcomes, but, analogously with the findings in the vegetarian adult population, an improvement in the quality of studies might facilitate finding more information on the possible positive impact of well-planned vegetarian diets during pregnancy and lactation. More epidemiological and interventional studies are warranted, in order to address the question as to whether vegetarian nutrition represents an advantage for the mother or poses nutritional issues that need further attention.

A Vegetarian Diet Is Associated with a Lower Risk of Cataract, Particularly Among Individuals with Overweight: A Prospective Study

BACKGROUND

Cataracts are caused by oxidative stress in the lens of the eyes and plant-based dietary patterns can contain a wide variety of protective antioxidants. However, strict vegetarians with inadequate vitamin B-12 intakes can have elevated homocysteine levels, which could increase the risk of cortical cataracts. Whether the benefits of a vegetarian diet outweigh its risks in the development of cataracts warrants investigation.

OBJECTIVE

Our aim was to study the prospective association between a Taiwanese vegetarian dietary pattern and cataract risk.

DESIGN

This was a prospective cohort study.

PARTICIPANTS/SETTING

The Tzu Chi Health Study recruited 6,002 participants from 2007 to 2009 at Dalin Tzu Chi Hospital. Diet was assessed through a validated food frequency questionnaire. Participants 40 years and older and without cataracts at recruitment (3,095 nonvegetarians and 1,341 vegetarians) were followed until the end of 2014, death, or occurrence of cataracts.

MAIN OUTCOME MEASURES

Cataract incident cases ((International Classification of Diseases, 9th Revision, Clinical Modification code 366) were identified by linkage to the National Health Insurance Research Database in Taiwan.

STATISTICAL ANALYSIS

Cox proportional hazard regression with age as the underlying scale was used to estimate the association between dietary patterns and cataract risk while adjusting for potential confounders.

RESULTS

Compared with nonvegetarians, vegetarians had higher intakes of soy, vegetables, nuts, whole grains, dietary fiber, vitamin C, folate, and vitamin A equivalent. In the 25,103 person-years of follow-up, 476 incident cases of cataracts were identified. A vegetarian diet was associated with a 20% reduced risk of cataracts (hazard ratio 0.80, 95% CI 0.65 to 0.99; P = 0.04) after adjusting for sex, education, smoking, alcohol drinking habits, physical activities, Tzu Chi volunteer status, hypertension, diabetes, hyperlipidemia, corticosteroid prescription, and body mass index (calculated as kg/m²). This association was more pronounced among individuals with overweight (defined as body mass index ≥24 in Taiwan [hazard ratio 0.70, 95% CI 0.50 to 0.99; P = 0.04]).

CONCLUSIONS

A vegetarian diet was associated with a lower risk of cataracts, particularly in study participants with overweight.

Intake and adequacy of the vegan diet. A systematic review of the evidence

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 B₂, Niacin (B₃), B₁₂, D, iodine, zinc, calcium, potassium, selenium. Vitamin B₁₂ 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, B₁, Β₆, 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 B₁₂, 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.

Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study

BACKGROUND

There is limited prospective evidence on possible differences in fracture risks between vegetarians, vegans, and non-vegetarians. We aimed to study this in a prospective cohort with a large proportion of non-meat eaters.

METHODS

In EPIC-Oxford, dietary information was collected at baseline (1993-2001) and at follow-up (≈ 2010). Participants were categorised into four diet groups at both time points (with 29,380 meat eaters, 8037 fish eaters, 15,499 vegetarians, and 1982 vegans at baseline in analyses of total fractures). Outcomes were identified through linkage to hospital records or death certificates until mid-2016. Using multivariable Cox regression, we estimated the risks of total (n = 3941) and site-specific fractures (arm, n = 566; wrist, n = 889; hip, n = 945; leg, n = 366; ankle, n = 520; other main sites, i.e. clavicle, rib, and vertebra, n = 467) by diet group over an average of 17.6 years of follow-up.

RESULTS

Compared with meat eaters and after adjustment for socio-economic factors, lifestyle confounders, and body mass index (BMI), the risks of hip fracture were higher in fish eaters (hazard ratio 1.26; 95% CI 1.02-1.54), vegetarians (1.25; 1.04-1.50), and vegans (2.31; 1.66-3.22), equivalent to rate differences of 2.9 (0.6-5.7), 2.9 (0.9-5.2), and 14.9 (7.9-24.5) more cases for every 1000 people over 10 years, respectively. The vegans also had higher risks of total (1.43; 1.20-1.70), leg (2.05; 1.23-3.41), and other main site fractures (1.59; 1.02-2.50) than meat eaters. Overall, the significant associations appeared to be stronger without adjustment for BMI and were slightly attenuated but remained significant with additional adjustment for dietary calcium and/or total protein. No significant differences were observed in risks of wrist or ankle fractures by diet group with or without BMI adjustment, nor for arm fractures after BMI adjustment.

CONCLUSIONS

Non-meat eaters, especially vegans, had higher risks of either total or some site-specific fractures, particularly hip fractures. This is the first prospective study of diet group with both total and multiple specific fracture sites in vegetarians and vegans, and the findings suggest that bone health in vegans requires further research.

The Change in the Content of Nutrients in Diets Eliminating Products of Animal Origin in Comparison to a Regular Diet from the Area of Middle-Eastern Europe

INTRODUCTION

The diet of Poles became similar to the western style of nutrition. It is rich in saturated fats, it contains significant quantities of salt, and has very low fruit and vegetable content. On the other hand, introducing an incorrectly planned diet that eliminates animal products may be associated with the risk of deficiencies of certain vitamins and minerals. Taking into account the regular diet of Poles, a properly balanced vegetarian menu may be a better and safer choice for the proper functioning of the organism.

AIM

The analysis of the content of individual types of vegetarian diets and a comparison with the menus of the regular diet of the Polish population.

MATERIALS AND METHODS

70 menus were subjected to a quantitative analysis, 10 menus for each 7 type of diet eliminating products of animal origin and regular diets without elimination. The caloricity of the designed diets was ±2000 kcal. The quantitative evaluation of the menus was performed using the Dieta 6d dietary program. Statistical significance was established at p ≤ 0.05.

RESULTS

It was observed that the regular diet of Poles (RD) featured the highest content of total fats, as well as saturated acids and cholesterol. The VEGAN diet was characterized by the lowest total protein content and the lack of wholesome protein and cholesterol. RD was characterized by the lowest average content of dietary fiber. The highest content of saccharose was observed in RD. Sodium content in RD significantly exceeded the recommended daily norm. RD featured insufficient content of the following minerals and vitamins: potassium, calcium, magnesium, iodine, Vitamin E, Vitamin C, folates, and Vitamin D. The norm for calcium has not been fulfilled also in milk-free and vegan diets. All of the analyzed diets lacked proper amounts of iodine and Vitamin D. The highest content of polyunsaturated fatty acids was observed in the VEGAN diet. The periodic elimination of meat and fatty dairy products should be included in the treatment of the metabolic syndrome, hypertensions, hyperlipidemia, obesity, and type 2 diabetes.

CONCLUSIONS

The regular diet of Poles turned out to be more dangerous for health in terms of deficiencies than properly balanced diets eliminating products of animal origin.

Does vegan diet influence umbilical cord vitamin B12, folate, and ferritin levels?

PURPOSE

To determine the influence of maternal diets on maternal and umbilical cord blood levels of vitamin B12, folic acid, ferritin, and hemoglobin.

METHODS

A prospective observational study on women who maintained the same diet for at least 3 months prior to, and throughout current pregnancy. Women were divided according to their diet. Diet questionnaires were filled in during the 3rd trimester. Blood samples for complete blood counts and levels of ferritin, vitamin B12, folate, and albumin were taken from the women prior to delivery and from the umbilical cord immediately after delivery.

RESULTS

The 273 enrolled women included 112 omnivores, 37 pescatarians, 64 vegetarians, and 60 vegans. There were no significant differences in the maternal B12 levels between the study groups (P = 0.426). Vegans had lower maternal ferritin levels compared to pescatarians (27 ± 17 vs 60 ± 74 ng/ml, respectively, P = 0.034), but not compared to vegetarians (P = 0.597), or omnivores (P = 1.000). There were no significant differences in the umbilical cord B12, folate, ferritin, and hemoglobin levels between the study groups. A sub-analysis that compared women who consumed multivitamins, B12 and iron supplements during pregnancy to women who did not, revealed differences in the levels of umbilical-cord B12 (1002 ± 608 vs 442 ± 151 pg/ml, respectively, P = 0.000) and maternal blood B12 (388 ± 209 vs 219 ± 95 pg/ml, respectively, P = 0.030) only among vegans, but not among omnivores.

CONCLUSION

Vegan diet does not change the umbilical cord levels of B12, folic acid, ferritin, and hemoglobin. Vegans who do not take any vitamin supplementation are at greater risk for B12 deficiency than omnivores.

Serum Vitamin B12, and Related MTRR and Cubilin Genotypes, Predict Neural Outcomes across the AD Spectrum

Epidemiological studies show mixed findings for serum vitamin B12 and both cognitive and regional volume outcomes. No studies to date have comprehensively examined, in non-supplemented individuals, serum B12 level associations with neurodegeneration, hypometabolism, and cognition across the Alzheimer's disease (AD) spectrum. Serum vitamin B12 was assayed from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL). Voxel-wise analyses regressed B12 levels against regional gray matter (GM) volume and glucose metabolism (p<.05, family-wise corrected). For ADNI GM, there were 39 cognitively normal (CN), 73 mild cognitive impairment (MCI), and 31 AD participants. For AIBL GM, there were 311 CN, 59 MCI, and 31 AD participants. Covariates were age, sex, baseline diagnosis, APOE4 status, and Body Mass Index (BMI). In ADNI, higher B12 was negatively associated with GM in the right precuneus and bilateral frontal gyri. When diagnostic groups were examined separately, only participants with MCI or above an established cutoff for CSF total tau showed such associations. In AIBL, higher B12 was associated with more grey matter in the right amygdala and right superior temporal pole, which largely seemed to be driven by CN participants that constituted most of the sample. Our results suggest that B12 may show different patterns of association based on clinical status and, for ADNI, AD CSF biomarkers. Accounting for these factors may clarify the relationship between B12 with neural outcomes in late-life.

Associations of Circulating Methylmalonic Acid and Vitamin B-12 Biomarkers Are Modified by Vegan Dietary Pattern in Adult and Elderly Participants of the Adventist Health Study 2 Calibration Study

BACKGROUND

Elevated plasma methylmalonic acid (MMA) is a functional biomarker of vitamin B-12 status but limited information is available on its prevalence in US vegetarians.

OBJECTIVES

The study examines the prevalence of plasma MMA ≥0.27 µmol/L in those consuming vegetarian diets, its associations with vitamin B-12 intake and biomarkers, and the modifying effect of vegetarian patterns on these associations.

METHODS

In this cross-sectional study (n = 785), concentrations of MMA, vitamin B-12, holotranscobalamin (holoTC), and homocysteine (Hcy) were determined in participants of the calibration substudy of the Adventist Health Study 2 (AHS-2). Vitamin B-12 intake from food, fortified food, and supplements was assessed by six 24-h recalls. Regression models were used to estimate ORs of having high MMA as related to vitamin B-12 status biomarkers, vitamin B-12 intake, and dietary pattern.

RESULTS

The prevalence of low vitamin B-12 status defined by serum vitamin B-12 <148 pmol/L, holoTC <35 pmol/L, MMA ≥0.27 and ≥0.37 μmol/L, or Hcy ≥15 μmol/L, and the OR of having high MMA did not differ by dietary pattern, possibly due to intake from fortified food and supplements. Total daily vitamin B-12 intake in the second tertile range of 4.4-14.5 μg/d reduced the likelihood of elevated MMA by 69%; and a doubling of vitamin B-12 intake was associated with a 4.3% decrease in plasma MMA. The association between log plasma MMA and biomarkers was modified by diet, with the vegan pattern showing an ∼3-fold stronger association with log serum vitamin B-12 and Hcy than did the nonvegetarian pattern.

CONCLUSIONS

The prevalence of vitamin B-12 intake <2.0 μg/d was 15.2% in vegans, 10.6% in lacto-ovo-vegetarians, and 6.5% in nonvegetarians. Given the irreversible neurological consequences of vitamin B-12 inadequacy, the importance of regular supplemental vitamin B-12 intake in adult and elderly individuals is stressed.