Vegetarianism — a path to health or a risk of deficiencies?

Aim of the study: The global shift towards vegan and vegetarian diets has garnered attention for their ethical, environmental, and potential health benefits. These diets are often rich in phytonutrients and antioxidants, which have been associated with lower levels of inflammatory markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6), suggesting a potential protective effect against systemic inflammation and oxidative stress.

Results: Evidence suggests that vegan and vegetarian diets, when well planned, can be rich in phytonutrients and antioxidants, which have been associated with lower levels of inflammatory markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6). These findings indicate a potential role in reducing systemic inflammation and oxidative stress, both of which are linked to neurodegenerative diseases. However, deficiencies in critical nutrients such as vitamin B12, DHA, EPA, and iron have been consistently associated with an increased risk of cognitive decline, mood disturbances, and neurodegenerative disorders. Additionally, the presence of antinutritional factors like phytates and oxalates may further impair nutrient absorption, necessitating careful dietary planning and supplementation. While plant-based diets provide anti-inflammatory and antioxidant benefits, their neurological implications depend on nutrient adequacy.

Aim of the study: Vegetarian and vegan diets have increased worldwide in the last decades, according to the knowledge that they might prevent coronary heart disease, cancer, and type 2 diabetes.

Results: Vegetarian and vegan diets have increased worldwide in the last decades, according to the knowledge that they might prevent coronary heart disease, cancer, and type 2 diabetes. Although plant-based diets are at risk of nutritional deficiencies such as proteins, iron, vitamin D, calcium, iodine, omega-3, and vitamin B12, the available evidence shows that well-planned vegetarian and vegan diets may be considered safe during pregnancy and lactation, but they require a strong awareness for a balanced intake of key nutrients. A review of the scientific literature in this field was performed, focusing specifically on observational studies in humans, in order to investigate protective effects elicited by maternal diets enriched in plant-derived foods and possible unfavorable outcomes related to micronutrient deficiencies and their impact on fetal development.

Aim of the study: Recently, vegetarian diets have experienced an increase in popularity. A vegetarian diet is associated with many health benefits because of its higher content of fiber, folic acid, vitamins C and E, potassium, magnesium, and many phytochemicals and a fat content that is more unsaturated.

Results: However, eliminating all animal products from the diet increases the risk of certain nutritional deficiencies. Micronutrients of special concern for the vegan include vitamins B-12 and D, calcium, and long-chain n-3 (omega-3) fatty acids. Unless vegans regularly consume foods that are fortified with these nutrients, appropriate supplements should be consumed. In some cases, iron and zinc status of vegans may also be of concern because of the limited bioavailability of these minerals.

Aim of the study: In recent decades, there has been an increasing interest in vegetarian diets. It is therefore interesting to analyse the benefits and risks of these diets.

Results: To this end, a review has been done on the benefits and risks of vegetarian diets. Vegetarian diets have been associated with different health benefits. On the contrary, nutritional deficiencies have been observed in those people who follow this type of diet, mainly in those risk groups such as pregnant and lactating women, children, adolescents, and elderly. Vegetarian diets may have some health benefits, however further studies are required.

Aim of the study: 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.

Results: 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.

Aim of the study: 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.

Results: 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.

Aim of the study: Plant-based diets (PBDs), characterized by minimal or no intake of animal-derived foods and increased consumption of vegetables, fruits, whole grains, legumes, soy products, nuts, seeds, and plant-based oils, have garnered attention for their health benefits and environmental sustainability. While substantial evidence links PBDs to reduced risk of chronic diseases, their role in pregnancy-related disorders remains underexplored.

Aim of the study: The increasing adoption of vegetarian dietary patterns among athletes (including lacto-ovo, lacto-, ovo-vegetarian, and vegan diets) has prompted growing interest in their potential effects on health and sports performance. Iron status remains one of the key nutritional concerns in this context, given the lower bioavailability of non-heme iron and the higher physiological demands of exercise.

Results: Available studies do not consistently indicate a higher prevalence of iron deficiency among vegetarian athletes compared with omnivores. Despite lower iron bioavailability, total dietary iron intake in vegetarians often equals or exceeds that of omnivores, and several adaptive mechanisms (such as enhanced absorption efficiency and reduced iron losses) may help preserve iron balance. Nevertheless, methodological heterogeneity across studies and the limited inclusion of elite or female athletes constrain firm conclusions. Current data suggest that vegetarian athletes are not inherently at greater risk of iron deficiency. However, in high-performance settings, individualized and evidence-based dietary planning remains essential to ensure optimal iron status and sustain athletic performance. Future research should clarify the interplay between diet composition, adaptive physiology, sex, and training load in determining iron metabolism among vegetarian athletes.

Aim of the study: Plant-based diets, including vegan and vegetarian patterns, are gaining popularity among physically active individuals, including amateur runners. While such diets may offer health benefits, they also carry a risk of inadequate intake of key nutrients, among which iron plays a crucial role.

Results: Nutritional knowledge was significantly greater in VEG and LOW groups versus OMN (p = 0.002). Iron intake correlated positively with nutritional knowledge (p = 0.014), while pHDI correlated negatively with BMI (p = 0.002). Well-planned plant-based diets supported adequate iron intake and diet quality in amateur athletes, with increased supplement use and nutritional awareness mitigating deficiency risks. Nutrition education and individual nutrition planning are advised for all athletes, with attention to iron status, especially in female runners.

Aim of the study: As plant-based (PB) diets become more common among UK children, understanding their nutritional adequacy and environmental impact is vital. This study addresses that lack of understanding through assessment of the nutrient content and greenhouse gas emissions for omnivorous, vegetarian, and vegan diets.

Results: Iodine intake remained inadequate in vegan children even with supplementation. Mean daily greenhouse gas (GHG) emissions differed significantly between diet groups, with omnivores having the highest emissions, while vegans had the lowest emissions: 46% lower than omnivores, and 20% lower than vegetarians. Well-planned PB diets can meet most nutrient needs in UK children when supported by fortified foods and supplements, while substantially reducing dietary GHG emissions compared with omnivorous diets. Shifting away from animal protein and dairy provides an opportunity for improving both nutritional quality and environmental sustainability.