Vitamin B12 – COBALAMIN
The last in the group of B vitamins, B12 is the largest and most complex vitamin of them all. It also plays a key role in aiding the normal functioning of the brain and nervous system. It is needed for the formation of blood and is involved in the metabolism of all cells, especially those affecting DNA regulation and synthesis as well as fatty acids and amino acids. No living creature or plant is capable of producing cobalamin, but microorganisms are as they contain the necessary enzymes. As these are found in animals and dairy products, many foods are still a primary, sound source of the nutrient.
Two steps are required for the body to absorb cobalamin from food. First, hydrochloric acid in the stomach separates it from the protein to which it is attached. It is then mixed up with a protein produced in the stomach called intrinsic factor and absorbed by the body. Some people have a medical condition which means their bodies don’t produce intrinsic factor though and so have trouble getting enough vitamin B12 from foods and dietary supplements.
WHAT DOES IT DO?
Cobalamin has many benefits such as reducing tiredness, keeping the immune system working properly, contributing to normal cell division, aiding the formation of red blood cells, and supporting natural energy production. It has been looked at as a treatment for many conditions including breast cancer, heart disease, high cholesterol and sickle cell disease. Studies suggest that it does not help with stroke risk or lung cancer however.
Low levels of cobalamin are more common in people over the age of 50 or those with digestive problems and certain types of anaemia. But any reduction can be felt. Even temporary low levels of the nutrient can cause fatigue, memory loss, weakness, and other problems relating to the nervous system.
One study showed that cobalamin supplements used with folic acid and vitamin B6, reduced the risks of the eye condition macular degeneration (AMD) in older women with heart disease or with multiple risk factors for heart disease.
WHERE IS IT FOUND?
Because the nutrient is found mostly in meat, fish and dairy, vegans and vegetarians are more susceptible to a deficiency. One of the best food sources to help fulfil daily requirements is clams. Just three ounces of these mollusks boast 84.1 μg of cobalamin. Beef is another good source and three ounces has 70.7 μg cobalamin. The amount is higher if the meat comes from grass-fed cattle. Oysters are another mollusk that contain a plentiful supply – six medium oysters have 16.4 μg of the nutrient. Then comes chicken, turkey, salmon, trout, and fortified soy and cereal products.
HOW MUCH DO YOU NEED?
Vitamin B12 can be consumed in large doses because any leftover amount is excreted by the body or stored in the liver for use when supplies run low. Amazingly, stores of B12 can actually last in the body for up to a year. The recommended dietary allowance, which includes the vitamin B-12 you get from both food and any supplements, is 0.4mcg per day for babies up to the age of six months, then 0.5mcg up to the age of one. Between the ages of one and three the amount is 0.9mcg per day and four to eight years it’s 1.2mcg, increasing to 1.8mcg per day in the nine to 13 age group. Teenagers and adults of both sexes are advised to have 2.4mcg daily, and pregnant women, 2.6mcg.
Even at high doses, cobalamin is fairly safe. While there aren’t very many side effects relating to consuming too much of it to be worried about, in rare cases, excess supplementation may cause numbness or tingling in the arms, hands and face. People with Leber’s Disease are especially warned not to take vitamin B12 supplements because they can cause damage to the optic nerve. People with a history of gout should be careful as the vitamin can trigger the condition in people who are susceptible. There is also a link between very high doses of cobalamin and certain cancers. One study showed that the risk of developing prostate cancer could triple. Less serious side effects include nausea, diarrhoea, and difficulty swallowing.