Vitamin B12 is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, as well as in the formation of blood.
Vitamin B12 is naturally present only in animal products, where it’s bound to the protein in those foods. During digestion, the hydrochloric acid in your stomach releases B12 from food, allowing the body to absorb it. Inability to absorb vitamin B12 from the intestinal tract can be caused by a condition called pernicious anemia, resulting in a vitamin B12 shortfall. People who do not eat animal foods and who don’t consume the suggested amount of vitamin B12 from fortified foods and dietary supplements are also prone to vitamin B12 deficiency. As you age, the risk of inadequate vitamin B12 absorption rises.
Vitamin B12 is central to proper neurological functioning. Studies show that vitamin B12 deficiency can lead to shaky movements and an unsteady gait, muscle weakness, vision problems, dementia, and mood disturbances. According to scientific research, these symptoms, and others, may occur when vitamin B12 levels are just slightly lower than normal. Vitamin B12 deficiency can cause disorientation and confusion, mimicking some of the signs of Alzheimer's disease. *
Relevant Health Areas
Pregnancy
UL (Tolerable Upper Intake Level) - is the highest level of intake that can be tolerated without the possibility of causing illness.
**Note that for some nutrients, there is not enough data to set a UL. However, this does not mean that consuming excess amounts poses no risks and instead indicates that there is a need for caution when consuming large amounts.
Values determined by the Institute of Medicine (IOM)
Vitamin B12 is present in animal products, including meat, poultry, seafood, milk, and eggs. If you skip or skimp on animal foods, consider fortified foods to fulfill the recommended daily amounts of vitamin B12.
Certain common medications may affect your vitamin B12 levels—talk to your doctor/or pharmacist about Vitamin B12 interactions.
Taking large doses of folic acid can mask a vitamin B12 deficiency, which could provoke irreversible neurological damage. The IOM (Institute of Medicine) advises limiting folic acid (from fortified foods and dietary supplements) intake to 1,000 micrograms daily for adults.
U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans 2010. 7th Edition. Washington, DC: U.S. Government Printing Office, December 2010.
Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington DC: National Academy Press; 1998:306-356.
Natural Standard. Vitamin B12 Bottom Line Monograph. http://naturalstandard.com/databases/herbssupplements/patient-vitaminb12...
Wolters M, Strohle A, Hahn A. Cobalamin: A critical vitamin in the elderly. Prev Med. 2004 Dec;39(6):1256-66.
Linus Pauling Institute. Micronutrient Information Center – Vitamin B12. Available at: http://lpi.oregonstate.edu/infocenter/vitamins/vitaminB12/ Accessed May, 25, 2011.
Older people may absorb significantly less of the vitamin B12 that occurs naturally in foods because they don’t produce as much of the stomach acid necessary to liberate vitamin B12 from food. For that reason, the Institute of Medicine (IOM) recommends that adults over 50 years of age get most of the suggested daily intake of vitamin B12 from fortified foods or dietary supplements. The form of vitamin B12 in fortified foods and dietary supplements is not bound to protein and is more easily absorbed. Some nutritional experts recommend that those older than 50 years of age may need even higher levels of Vitamin B12, ranging from 50 to 400 mcg/day.
People who do not eat animal foods, or don’t eat enough of them and don’t consume the recommended amounts of vitamin B12 from fortified foods, should consider taking vitamin B12 in the form of dietary supplements, rely on fortified foods, or both.






