Vitamin B12

# What is vitamin B12? Vitamin B12 (cobalamin) is a water-soluble vitamin and is essential for the nervous system, blood formation, DNA synthesis, homocysteine metabolism and the immune system. Genetic variations can influence the absorption, transport and metabolism of vitamin B12. A vitamin B12 deficiency can lead to anemia (megaloblastic anemia), neurological disorders (mood swings, depression, memory disorders...), nerve pain, fatigue, exhaustion and a weakened immune system. ## Examples of foods rich in vitamin B12: > ## Good to know > > Animal foods are the frontrunners when it comes to vitamin B12 content. Fish, meat, seafood, eggs and dairy products are good sources. > Among plant sources, sauerkraut, fermented products such as miso, natto, kimchi and fermented vegetables are the most important. However, it should not go unmentioned that plant-based foods only contain very small amounts of B12 and that this is often present in a form that cannot be utilized by the body. # What does genetics have to do with it? We are investigating a gene for vitamin B12 metabolism: The FUT2 gene (fucosyltransferase 2 gene) carries the blueprint in the cells for an enzyme that is involved in the production of the so-called intrinsic factor (IF), among other things. This factor is important for the absorption of vitamin B12 in the intestine and in this way influences the vitamin B12 level. The binding of the vitamin to the intrinsic factor is therefore a prerequisite for the absorption of vitamin B12 through the intestinal wall into the blood. Variants of the FUT2 gene therefore have an effect on vitamin B12 levels, among other things. - Genotype A/A shows an increased vitamin B12 level. - The G/G genotype shows a low vitamin B12 level. - Genotype A/G shows a normal vitamin B12 level.