What is vitamin B12 and what does it do?
Vitamin B12 is a nutrient that helps keep the body’s nerve and blood cells healthy and helps make DNA, the genetic material in all cells. Vitamin B12 also helps prevent a type of anemia called megaloblastic anemia that makes people tired and weak.
Two steps are required for the body to absorb vitamin B12 from food. First, hydrochloric acid in the stomach separates vitamin B12 from the protein to which vitamin B12 is attached in food. After this, vitamin B12 combines with a protein made by the stomach called intrinsic factor and is absorbed by the body. Some people have pernicious anemia, a condition where they cannot make intrinsic factor. As a result, they have trouble absorbing vitamin B12 from all foods and dietary supplements. [NIH]
How much vitamin B12 do I need? Read more about Vitamin B12 here.
Vitamin B12 is found naturally in a wide variety of animal foods and is added to some fortified foods. Plant foods have no vitamin B12 unless they are fortified. You can get recommended amounts of vitamin B12 by eating a variety of foods include the following:
- Beef liver and clams, which are the best sources of vitamin B12.
- Fish, meat, poultry, eggs, milk, and other dairy products, which also contain vitamin B12.
- Some breakfast cereals, nutritional yeasts and other food products that are fortified with vitamin B12. To find out if vitamin B12 has been added to a food product, check the product labels.
What about Vegans how do they get Vitamin B12?
Foods fortified with B12 are also sources of the vitamin although they cannot be regarded as true food sources of B12 since the vitamin is added in supplement form, from commercial bacterial production sources, such as cyanocobalamin. Examples of B12-fortified foods include fortified breakfast cereals, fortified soy products, fortified energy bars, and fortified nutritional yeast. The UK Vegan Society, the Vegetarian Resource Group, and the Physicians Committee for Responsible Medicine, among others, deny that non-animal food sources of vitamin B12 are reliable and recommend that every vegan who is not supplementing consume B12-fortified foods.
According to Stephen Walsh, a UK Vegan Society trustee, and other members of the International Vegetarian Union science group (IVU-SCI), in October 2001. To get the full benefit of a vegan diet, vegans should do one of the following:
- eat fortified foods two or three times a day to get at least three micrograms (μg or mcg) of B12 a day or
- take one B12 supplement daily providing at least 10 micrograms or
- take a weekly B12 supplement providing at least 2000 micrograms.
Source: National Institute of Health,, Medical Encyclopedia, Wikipedia, Medical Dictionary, Mayo Clinic.