Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in the metabolism of every cell of the human body. It is particularly important in the normal functioning of the nervous system via its role in the synthesis of myelin, and in the maturation of developing red blood cells in the bone marrow. Vitamin B12 is one of eight B vitamins. It is the largest and most structurally complex vitamin. The only organisms to produce vitamin B12 are certain bacteria, and archaea. Given vitamin B12’s role in cell production, adequate levels of this vitamin are needed to promote healthy hair, skin and nails.
Many foods are a natural source of B12 because of bacterial symbiosis. It is produced by some of the gut flora of herbivores. Carnivores, of course, eat herbivores. Also algae and plants get it from symbiosis. Most omnivorous people in developed countries obtain enough vitamin B12 from consuming animal products, including meat, milk, eggs, and fish. Grain-based foods are often fortified by having the vitamin added to them. Vitamin B12 supplements are available in single agent or multivitamin tablets. Because there are few non-animal sources of the vitamin, vegans are advised to consume a dietary supplement or fortified foods for B12 intake, or risk serious health consequences.
Vitamin B12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system. At levels only slightly lower than normal, a range of symptoms such as fatigue, lethargy, difficulty walking (staggering balance problems) depression, poor memory, breathlessness, headaches, and pale skin, among others, may be experienced, especially in elderly people (over age 60) who produce less stomach acid as they age, thereby increasing their probability of B12 deficiencies. This deficiency can also cause symptoms of mania and psychosis.
Vitamin B12 deficiency is most commonly caused by low intakes, but can also result from malabsorption, certain intestinal disorders, low presence of binding proteins, and use of certain medications. Vegans - people who choose to not consume any animal-sourced foods - are at risk because plant-sourced foods do not contain the vitamin. The elderly who have diets with limited animal-sourced foods are vulnerable populations for that reason and also because intestinal absorption declines with age, a consequence of low stomach acid. Vitamin B12 deficiency may occur in between 40% to 80% of the vegetarian population who are not also consuming a vitamin B12 supplement. In Hong Kong and India, vitamin B12 deficiency has been found in roughly 80% of the vegan population as well. Vegans can avoid this by consuming a dietary supplement or eating B12-fortified foods like cereals, plant-based milks, and nutritional yeast as a regular part of their diet.
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