[Vegetarian and vegan diets and their impact on health].

Vegetarian and vegan diets are increasing in the population, but the prevalence remains low (< 3 %). Vegetarians consume diary and eggs while vegans do not consume or use any animal derived products. Vegetarians have a low risk of deficiency except for iron deficiency with anemia in pre-menopausal women. Vegans should receive a mandatory vitamin B12 substitution because of an important risk of deficiency. Furthermore, vegans are at higher risk of iron and calcium deficiency with higher rates of osteoporotic fracture and iron deficiency anemia. Dietary advice is recommended, particularly for vegans, even though no clear recommendations can be found in the literature. These diets seem to be associated with a reduction in cardio-vascular risk factors, but this association remains to be confirmed.