Are dietary sources of vitamin B12 restricted to food of animal origin?

By William Aird

Yes, vitamin B12 is synthesized solely by microorganisms (ruminants obtain Cbl from the foregut) and is naturally present in foods of animal origin, including fish, meat, poultry, eggs, and dairy products. In addition, fortified breakfast cereals and fortified nutritional yeasts are readily available sources of vitamin B12 that have high bioavailability. The bioavailability of vitamin B12 is about three times higher in dairy products than in meat, fish, and poultry, and the bioavailability of vitamin B12 from dietary supplements is about 50% higher than that from food sources. Vegans are at increased risk for developing vitamin B12 deficiency. Read more here.

*DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for vitamin B12 is 2.4 mcg for adults and children aged 4 years and older [21]. FDA does not require food labels to list vitamin B12 content unless vitamin B12 has been added to the food. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet. From NIH.