Vitamin B12 is an essential nutrient that helps the body create DNA, nourishes the brain and nervous system, and assists with the formation of healthy red blood cells. The nutrient occurs naturally in meat, fish, and dairy products, and can be created in a laboratory.
Some people lack a protein that helps the body absorb vitamin B12 from foods and supplements. A lack of B12 can put you at higher risk for a specific type of anemia that makes you feel weak and tired.
Depression Prevention and Treatment
Vitamin B12 plays a role in serotonin production, so a deficiency may be connected with clinical depression. In one study, disabled older women with a B12 deficiency were found to have double the risk of severe depression as those without a deficiency.
In addition, high levels of vitamin B12 have been associated with better chances of recovery from major depressive disorder.
Reduced Risk of Macular Degeneration
Supplementing with vitamin B12 is believed to lower homocysteine in the bloodstream, which may help prevent age-related macular degeneration, an eye disease that can cause blindness in older adults. In one study of 5,000 women age 40 and up, those who took supplements of vitamins B12, B6, and folic acid had 34% fewer cases of macular degeneration after seven years than a placebo group. Their risk of severe degeneration was 41% lower.
The recommended daily intake of vitamin B-12 for adults is 2.4 micrograms.
Vitamin B12 is also found in animal products, such as eggs, meat, fish, poultry, milk, and some nutritional yeast products. Vitamin B12 does not naturally occur in most plant foods, so fortified breakfast cereals are recommended for vegetarians.