Nutritional Supplementation with Chlorella pyrenoidosa Lowers Serum Methylmalonic Acid in Vegans and Vegetarians with a Suspected Vitamin B₁₂ Deficiency.

Since vitamin B12 occurs in substantial amounts only in foods derived from animals, vegetarians and particularly vegans are at risk of developing deficiencies of this essential vitamin. The chlorella used for this study is a commercially available whole-food supplement, which is believed to contain the physiologically active form of the vitamin. This exploratory open-label study was performed to determine if adding 9 g of Chlorella pyrenoidosa daily could help mitigate a vitamin B12 deficiency in vegetarians and vegans.