Resumen: Western countries have greatly increased the number of people who adhere to a vegetarian or vegan diet for health reasons or animal right causes. This diet is presented as a balanced and healthy diet, however recommendations for a vegetarian and vegan diet remain controversial in the world of nutrition because of possible nutritional deficits. The aim of this study was to show recent evidence of protective and risk factors of these diets for chronic non-communicable diseases associated with nutrition, as well as their use during the life cycle. We also considered the critical nutrients necessary to obtain a vegetarian/vegan diet without nutritional risks. In general, these diets were rich in dietary fibers, magnesium, phytochemicals, antioxidants, vitamins C and E, iron, folic acid and polyunsaturated fatty acids (n-6), but low in cholesterol, total fat and saturated fat, iron, zinc, vitamin A, B12 and D, and especially the omega 3 fatty acids EPA and DHA.