An essential nutrient that keeps your metabolism in check, vitamin B12 is found in many foods, especially animal products. Also available in supplement form, vitamin B12 is involved in regulating metabolism, aiding in the formation of red blood cells, and maintaining the central nervous system. Vitamin B12 is also required for the proper function and development of the brain.
Why Use Vitamin B12?
Vitamin B12 is said to help with a host of health concerns.
For instance, research suggests that vitamin B12 may preserve your eyesight as you get older, fight heart disease, aid stroke recovery, and rev up your defense against some forms of cancer.
Other purported uses include to enhance mood, increase energy, improve memory, stimulate the immune system, promote healthy sleep, and slow the aging process.
Signs of Deficiency
Vitamin B12 deficiency is most common among adults over age 50, vegetarians, vegans, people who have undergone gastrointestinal surgery, and people with digestive disorders (such as celiac disease and Crohn's disease).
Signs of vitamin B12 deficiency include:
Loss of balance
Numbness or tingling in the arms and legs
So far, scientific support for the claim that B12 in excess of the daily requirements can treat any health condition is fairly lacking. Here's a look at some of the studies that have been done.
When applied to the skin, vitamin B12 may help fight eczema. For a 2004 study from the British Journal of Dermatology, researchers assigned 49 eczema patients to eight weeks of twice-daily treatment with a placebo or a cream containing vitamin B12. By the study's end, those using the vitamin B12 cream had experienced a greater decrease in the severity of their eczema (compared to those using the placebo cream).
2) Heart Disease
Taking vitamin B12 may lower homocysteine (an amino acid thought to increase heart disease risk when it is present in elevated levels). According to a 2000 report from Seminars in Thrombosis and Hemostasis, daily supplementation with both 0.5 to 5 mg of folic acid and about 0.5 mg of vitamin B12 may significantly reduce homocysteine levels.
Early research indicates that vitamin B12 may protect against some forms of cancer. In a 2003 study from Cancer Causes & Control, for instance, scientists examined the dietary habits of 214 women with cervical dysplasia. (A condition marked by abnormal changes in the cells on the surface of the cervix, cervical dysplasia can lead to cervical cancer if not treated.) Analyzing their findings, the study's authors determined that women who use vitamin B12 supplements and have a high intake of folate, riboflavin, and thiamin may be less likely to develop cervical cancer.
Foods with Vitamin B12
To get your fill of vitamin B12, include the following foods in your diet:
Fortified cereal (1.5 to 6 mcg per serving)
Wild rainbow trout (5.4 mcg per 3-ounce serving)
Sockeye salmon (4.8 mcg per 3-ounce serving)
Plain yogurt (1.4 mcg per cup)
White tuna (1 mcg per 3-ounce serving)
Milk (0.9 mcg per cup)
Eggs (0.6 mcg per egg)
Roasted chicken (0.3 mcg per half-breast)
The recommended dietary allowance (RDA) for vitamin B12 is 2.4 mcg/day for people ages 14 and older. If you're concerned that you're not getting enough vitamin B12 from food, talk to your doctor about using vitamin B12 supplements.
Although vitamin B12 is likely safe for most people when taken in reasonable amounts, it may cause certain side effects (including diarrhea, blood clots, itching, and severe allergic reactions).
In addition, combining vitamin B12 with chloramphenicol (an antibiotic medication) may produce harmful effects.
Vitamin B12 should be avoided by people with Leber's disease (a type of eye disease). When taken by people with Leber's disease, vitamin B12 can damage the optic nerve and possibly contribute to blindness.
It's important to keep in mind that self-treating a condition and avoiding or delaying standard care may have serious consequences.
Vitamin B12 Injections
Vitamin B12 injections are typically used to treat vitamin B12 deficiency in people who have trouble absorbing the vitamin (such as individuals with digestive disorders). Although some proponents suggest that vitamin B12 injections can also help promote weight loss, there's no evidence to support this claim.
If you're considering the use of vitamin B12 for a health condition (or are concerned that you're not getting enough B12 in your daily diet), talk with your healthcare provider to discuss whether it's appropriate for you.