Vitamin B12 is one of eight water-soluble B vitamins. Playing a significant role in the development and maintenance of your body's nervous system, vitamin B12 is also involved in red blood cell and nucleic acids production. Commons sources of vitamin B12 include most meat and dairy products. While no toxic effects are known from taking high doses of this vitamin, deficiencies in vitamin B12 can be harmful and potentially fatal.
Role of Vitamin B12
Vitamin B12 plays significant roles in forming red blood cells and maintaining a healthy nervous system. With help from vitamin B12, folate starts production of new red blood cells inside your body. It is also responsible for maintaining the protective covering around your nerve cells called the myelin sheath. Production of DNA and RNA, your body's genetic material, requires vitamin B12 as well.
Recommended Daily Amount for Vitamin B12
The safe range for vitamin B12 intake is between 3 and 10 mcg. Although, the recommended dietary allowance for vitamin B12 is listed as 2 mcg for adults, with 3 mcg per day required for women who are pregnant. As you get older, your ability to absorb vitamin B12 decreases, which explains why the elderly may need B12 supplementation. Strict vegans may also require vitamin B12 supplements since this vitamin comes mainly from animal food sources, such as meat, eggs and cheese.
Sources of Vitamin B12
Found naturally in protein-rich animal food sources, vitamin B12 is abundant in meat and dairy products. Sources meeting the recommended daily allowance of vitamin B12 in a single serving include tuna fish, eggs, cottage cheese and liver. Multivitamin supplements also contain the recommended daily allowance for vitamin B12 in one dose. Cyanocobalamin is the primary form of vitamin B12 found in food and nutritional supplements.
Vitamin B12 Toxicity and Deficiency
No toxicity symptoms for vitamin B12 have been reported for doses exceeding its recommended dietary allowances. However, deficiencies in this vitamin, especially during fetal development and infancy, may cause irreversible nervous system damage. For this reason, pregnant women should consume vitamin B12 fortified foods or supplements. Signs of nerve damage as a result of vitamin B12 deficiency include gradual paralysis, muscle spasms and nervous ticks.
References
- "Advanced Nutrition and Human Metabolism"; Sareen Gropper, Ph.D.; 2008
- "Nutrition: Concepts and Controversies"; Frances Sizer, R.D.; 2007
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