Vitamin B12, also known as cobalamin, is present in animal diets. It can also be used as a supplement or added to foods. Vitamin B12 is required for the production of red blood cells and DNA. It also plays an important role in the formation and function of brain and nerve cells.
Vitamin B12 binds to the protein found in our diets. Hydrochloric acid and enzymes in the stomach break down vitamin B12 into its free form. Vitamin B12 then binds with a protein known as intrinsic factor, allowing it to be absorbed deeper down in the small intestine.
B12 in its free form is found in supplements and fortified meals, making it easier to absorb. Vitamin B12 pills come in a variety of forms. Although some believe that particular forms—such as sublingual tablets or liquids placed under the tongue to be absorbed through the mouth’s tissues—absorb better than regular tablets, investigations have found no significant difference. Vitamin B12 tablets come in high doses much beyond the recommended dietary requirement, however these high doses are not always the amount that is absorbed because a suitable level of intrinsic factor is also required. Doctors may provide B12 injections in the muscle in cases of severe vitamin B12 insufficiency caused by a lack of intrinsic factor (pernicious anaemia).
Amounts to Consider
The Recommended Daily Allowance (RDA) for men and women aged 14 and up is 2.4 micrograms (mcg) per day. The dose increases to 2.6 mcg and 2.8 mcg daily during pregnancy and lactation, respectively.
The maximum daily amount that is unlikely to cause undesirable side effects in the general population is known as the Tolerable Upper Intake Level (UL). There is no defined hazardous level for vitamin B12, hence there is no upper limit. Supplementing with 25 mcg or more per day, however, may raise the risk of bone fractures, according to some data.
Toxicity and Deficiency Symptoms
Deficiency
Because some persons with a deficit can have normal B12 blood levels, measuring vitamin B12 in the blood isn’t the greatest technique to tell if they’re deficient. Methylmalonic acid, a protein breakdown product, and homocysteine levels in the blood are better indicators of vitamin B12 action. A vitamin B12 deficiency raises these numbers. Vitamin B12 deficiency is believed to affect up to 15% of the general population.
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