Vitamin B12 in adults on vegetarian and vegan diets.

Plant-based dietary patterns are beneficial for cardiometabolic health and are associated with a lower risk of multiple diseases, including ischemic heart disease and several types of cancer. For these reasons, they are increasingly recommended by the main medical societies and dietary guidelines. However, if not properly planned, these dietary patterns can lead to insufficient intake of certain nutrients, including vitamin B12. Specifically, people who follow vegetarian or vegan diets usually have a low or no intake of vitamin B12, since the dietary sources of this vitamin are foods of animal origin. Given that this is an essential nutrient, whose deficiency can lead to serious health consequences, it is essential to have clear guidelines for the prevention, diagnosis and timely treatment of vitamin B12 deficiency in the population with a vegetarian and vegan diet.