Vitamin B12, also known as cobalamin (because it contains the trace element cobalt), is an incredibly important B vitamin.
It is necessary for the production of red blood cells and plays an important role in maintaining the health of nerve cells and in the formation of genetic material.
All of the B vitamins, including B12 are water-soluble, meaning that the body does not store them, so we must consume them daily. The best place to get B vitamins is from our food, as for most people, when vitamins are obtained through food they are easily absorbed and utilised because you are also consuming co-nutrients that assist with the uptake and absorption.
Vitamin B12 however, is somewhat different from the other B group vitamins as it is absorbed directly out of the stomach into the blood, rather than the small intestine, the place from where the other B vitamins are absorbed. The stomach releases a substance called intrinsic factor, to which the B12 must bind, for it to be absorbed.
All B vitamins help the body convert food, specifically carbohydrates, into fuel (in this case, glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and proteins. B complex vitamins are needed for healthy skin, hair, eyes, and liver detoxification. They also help the nervous system to function properly.
Vitamin B12 works closely with vitamin B9, also called folate, to help make red blood cells and to transport carbon around the body, essential for almost every internal process. There has been a lot of interest in B12 more recently due to its role in mood regulation. Folate and B12 work together to produce S-adenosylmethionine (SAMe), a compound involved in immune function and mood.
Vitamin B12 is a particularly important vitamin for maintaining healthy nerve cells, and it helps in the production of DNA and RNA, our genetic material.
Vitamins B12, B6, and B9 work together to control blood levels of the amino acid homocysteine. High levels of homocysteine have been associated with heart disease. However, researchers have not concluded whether homocysteine is a cause of heart disease or just a marker that indicates someone may have heart disease.
The only food sources of B12 are animal foods. Plants don’t contain B12 – in fact they don’t need it – and as a result, people who eat a vegan diet are at greater risk of deficiency. Some species of gut bacteria also produce vitamin B12 however, studies suggest that after not consuming animal foods for five years, B12 gut bacteria production is no longer sufficient and supplementation for people eating a vegan diet is necessary.
There are numerous reasons why someone might be deficient in B12 which include an insufficient dietary intake, poor intrinsic factor production and undiagnosed coeliac disease.
It is rare for young people to be deficient in vitamin B12, but it is not uncommon for older people to be mildly deficient. This may be because their diets are not as nourishing due to changes in appetite or desire/capacity to cook, or because it becomes harder to absorb because of a lack of intrinsic factor. Low levels of B12 can cause a range of symptoms including fatigue, shortness of breath, diarrhoea, nervousness, numbness, or a tingling sensation in the fingers and toes.
An untreated deficiency can result in a type of anaemia and damage to the nervous system and a simple blood test can inform you of your B12 status. Intramuscular vitamin B12 injections form the basis of most treatment plans. If you think you have a B vitamin deficiency, it’s always best to talk to your GP or a health professional before supplementing.