Vitamin B 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 B (B). Because B 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 B supplement. Studies determining the dose and frequency of B to be taken by healthy individuals on a plant-based diet to support an adequate B status are scarce. Here, we summarize the natural sources, metabolic requirements, biomarker findings with and without supplementation with B, and current recommendations to help prevent vitamin B deficiency in healthy individuals adhering or transitioning to plant-based diets. This review focuses on the prevention of vitamin B 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 B resulting from pernicious anemia due to atrophic gastritis, other acquired causes of B malabsorption or to those with genetic disorders that impair vitamin B absorption, transport and utilization.