Vitamin B12 is a water-soluble vitamin that exists in several forms. Vitamin B12 is necessary for the normal function of the brain and the nervous system, red blood cell production, fat and protein breakdown, and the synthesis of DNA.
Fish, meat, poultry, eggs and milk are rich sources of vitamin B12. It is generally not found in plant-based food sources, which means vegetarians and vegans are at a higher risk of vitamin B12 deficiency.
A genetic variant in the FUT2 gene is associated with an increased risk of vitamin B12 deficiency. This means individuals with the FUT2 variant will need to eat foods that are high in vitamin B12, including clams or beef liver, to meet the recommended daily intake for vitamin B12.