Vitamin B12 injections are very popular. People often believe they'll act as a safety net and help to ensure adequate nutrient intake. Supplementing with vitamin B12 is particularly common because deficiency is widespread.
In fact, many people regularly get injections with vitamin B12. These are claimed to help with energy levels, brain function and weight loss, to name a few. Vitamin B12 is a water-soluble vitamin, also known as cobalamin. It plays a vital role in brain function and the production of DNA and red blood cells.
Chemically, vitamin B12 can exist in a number of different forms, but all of them contain the mineral cobalt. The vitamin can be stored in the liver for a long time, so it may take a few years for a deficiency to develop. The recommended daily intake (RDI) of vitamin B12 is 6 micrograms per day. Deficiency is common, especially in people who follow a vegetarian or vegan diet. In fact, it's thought that up to 90% of people following these diets have a deficiency. This is because B12 is only found naturally in animal foods.
However, vegans and vegetarians are not the only ones who are deficient. Even some meat eaters don't absorb it very well. Unlike other vitamins, the absorption of vitamin B12 depends on a protein produced in your stomach, called intrinsic factor. Intrinsic factor binds to vitamin B12, so that you can absorb it into the blood. People who don't produce enough intrinsic factor can become deficient. Deficiency is particularly common in elderly people, because the ability to absorb vitamin B12 can decrease with age. Other people at risk of deficiency include those who have had intestinal surgery, including weight loss surgery. Those with diseases that affect the gut, such as Crohn's disease or celiac disease, are also at risk. An untreated vitamin B12 deficiency can lead to neurological problems or pernicious anemia, which occurs when your body doesn't have enough B12 to produce the amount of red blood cells it needs.