Nutritional status of flexitarians compared to vegans and omnivores - a cross-sectional pilot study

Dietary selective effects manifest in the human gut microbiota from species composition to strain genetic makeup

Diet significantly influences the human gut microbiota, a key player in health. We analyzed shotgun metagenomic sequencing data from healthy individuals with long-term dietary patterns-vegan, flexitarian, or omnivore-and included detailed dietary surveys and blood biomarkers. Dietary patterns notably affected the bacterial community composition by altering the relative abundances of certain species but had a minimal impact on microbial functional repertoires. However, diet influenced microbial functionality at the strain level, with diet type linked to strain genetic variations. We also found molecular signatures of selective pressure in species enriched by specific diets. Notably, species enriched in omnivores exhibited stronger positive selection, such as multiple iron-regulating genes in the meat-favoring bacterium Odoribacter splanchnicus, an effect that was also validated in independent cohorts. Our findings offer insights into how diet shapes species and genetic diversity in the human gut microbiota.

Nutritional Considerations of Plant-Based Diets for People With Food Allergy

Plant-based diets (PBD) have been reported throughout history, but are increasingly common in current times, likely in part due to considerable emphasis on climate change and human health and wellness. Many dietary organisations around the world endorse well-planned, nutritionally adequate PBD, which exclude some or all forms of animal-based foods. However, special attention must be given to patients who follow PBD and also have food allergy (FA), as avoidance may increase the risk of developing nutritional deficiencies, including poor growth in children, weight loss in adults and vitamin and mineral deficiencies. Given the increasing prevalence of both PBD and food allergen avoidance diets, healthcare providers are likely to counsel patients with FA who also follow a PBD. In this review, an overview of PBD in patients with FA is provided, including recent trends, macro- and micronutrient needs, and growth for children and weight gain considerations for adults. With regard to a PBD, special attention should be given to ensure adequate fat and protein intake and improving the bioavailability of several minerals such as iron, zinc, iodine, calcium and magnesium, and vitamins such as A, B2, B12 and D. Although the collective data on growth amongst children following a PBD are varied in outcome and may be influenced in part by the type of PBD, growth must be regularly monitored and in adults weight gain assessed as part of any clinical assessment in those people with FA.

Cardiovascular Health and Diet Quality among Vegetarians, Vegans and Omnivores: Insights from a Large Urban Population in Poland

Background/Objectives: Dietary habits are among the most significant determinants of health. The aim of this study was to assess the nutritional quality and cardiovascular profiles of individuals following plant-based diet. Methods: The study population comprised 199 individuals (136 women, 63 men; mean age 33.9  ±  8.9 years) including vegans (VG; n = 50), vegetarians (VN; n = 101) and omnivores (OV; n = 48). In this analysis the following procedures were assessed: a questionnaire interview, anthropometric and blood pressure measurements, and a blood sample collection. Dietary patterns were evaluated using the Food Frequency Questionnaire and a 24-h dietary recall. Results: Vegans exhibited the lowest protein intake relative to the other groups (p < 0.05) and a significantly higher intake of polyunsaturated fatty acids and lower intake of cholesterol compared to VN and OV (p < 0.05). Vegans had significantly lower levels of serum cholesterol, LDL cholesterol, and triglycerides, fasting glucose and high-sensitivity C-reactive protein (p < 0.05). No cases of overweight or obesity were observed among VN and VG participants. No instances of impaired fasting glucose or elevated blood pressure were noted among vegans. Hypercholesterolemia was identified in 56.2% of OV, 26.7% in VN and 16.0% in VG (p < 0.05), elevated blood pressure was recorded in one vegetarian and in 6.2% of OV participants. Conclusions: Our research indicates that plant-based diets are associated with a better cardiovascular profile compared to traditional diets. Moreover, suboptimal intake of essential nutrients, underscores the need for more effective public health interventions and improved nutrition education regardless of dietary patterns.

Vitamin B12 Status and Supplementation in Plant-Based Diets

Plant-based diets are increasingly popular worldwide. A well-planned plant-based diet lowers the risk of cardiovascular disease, type 2 diabetes and certain cancers. In contrast, a poorly planned plant-based diet increases the risk of certain micronutrient deficiencies, chiefly, vitamin B12 (B12). Because B12 is not present in plants or in unfortified plant-based foodstuffs, the safest way to prevent its deficiency in plant-based diets is to take an oral B12 supplement. Studies determining the dose and frequency of B12 to be taken by healthy individuals on a plant-based diet to support an adequate B12 status are scarce. Here, we summarize the natural sources, metabolic requirements, biomarker findings with and without supplementation with B12, and current recommendations to help prevent vitamin B12 deficiency in healthy individuals adhering or transitioning to plant-based diets. This review focuses on the prevention of vitamin B12 deficiency in healthy individuals adhering to plant-based diets. The information covered in this review does not apply to individuals suffering from autoimmune-based malabsorption of vitamin B12 resulting from pernicious anemia due to atrophic gastritis, other acquired causes of B12 malabsorption or to those with genetic disorders that impair vitamin B12 absorption, transport and utilization.

Plant-based diets and cardiovascular risk factors: a comparison of flexitarians, vegans and omnivores in a cross-sectional study

BACKGROUND

The growing trend towards conscious and sustainable dietary choices has led to increased adoption of flexitarian diets, characterised by plant-based eating habits with occasional consumption of meat and processed meat products. However, the cardiovascular disease (CVD) risk factors associated with flexitarian diets compared to both vegans and omnivores remain underexplored.

METHODS

In this cross-sectional study, 94 healthy participants aged 25-45 years, categorized into long-term flexitarians (FXs ≤ 50 g/day of meat and meat products, n = 32), vegans (Vs, no animal products, n = 33), and omnivores (OMNs ≥ 170 g/day of meat and meat products, n = 29) were included. Various CVD risk factors were measured, including fasting blood samples for metabolic biomarkers, body composition analysis via bioimpedance, blood pressure measurements, arterial stiffness evaluated through pulse wave velocity (PWV) and metabolic syndrome (MetS) severity was determined using browser-based calculations (MetS-scores). Dietary intake was assessed using a Food Frequency Questionnaire (FFQ), diet quality was calculated with the Healthy Eating Index-flexible (HEI-Flex), while physical activity levels were recorded using the validated Freiburger questionnaire.

RESULTS

The data showed that FXs and Vs had more beneficial levels of insulin, triglycerides, total cholesterol, and LDL cholesterol compared to OMNs. Notably, FXs revealed the most favorable MetS-score results based on both BMI and waistline, and better PWV values than Vs and OMNs. In addition, FXs and Vs reported higher intake rates of vegetables, fruit, nuts/seeds and plant-based milk alternatives.

CONCLUSION

The flexitarian diet appears to confer cardiovascular benefits. While Vs had the most favorable results overall, this study supports that reducing meat and processed meat products intake, as in flexitarianism, may contribute to CVD risk factor advantages.