Vitamin B12 sources in non-animal foods: a systematic review

Interest in plant-based diets and vegetarianism is increasing worldwide, however, a concern for total vegetarians is vitamin B12 (B12) deficiency. We conducted a systematic review to investigate non-animal food sources of B12. Databases were PubMed, LILACS, Cochrane, Embase and Google Scholar, up to September 9, 2020. Quality of the eligible studies were assessed. We identified 25 studies which assessed B12 content in seaweeds, mushrooms, plants and fermented foods. Initial studies were microbiological bioassay, ELISA and HPLC. In the last decade, more sensitive method for real B12 determination was used, the liquid chromatography-electrospray ionization tandem mass spectrometry chromatograms. Real B12 content varied from mean (SD) mcg/portion size of seaweed hijiki 3 x 10(-3)/7 g to non 1.03-2.68/sheet; mushroom white button cap 2 x 10(-3) (7 x 10(-4)/20 g dry weight (dw) to shiitake 0.79(0.67)-1.12 (0.78)/20g dw; and fermented foods from soy yogurt 20/cup. It is possible that daily recommendations for B12 can be met by a varied diet containing non-animal B12 food sources. Future research should consider different methods of storage, preparation, fermented foods and standardization of the production of certain foods.

Automated summary

Interest in plant-based diets and vegetarianism is increasing worldwide. This systematic review investigated non-animal food sources of vitamin B12 (B12) for total vegetarians. The study found that seaweeds, mushrooms, plants, and fermented foods contain varying levels of B12. A varied diet containing these non-animal B12 sources may meet daily B12 requirements.