Live Well Vitamins & Lifestyle Guide

Vitamin B-12 (Cobalamin)

Vitamin B-12 (cobalamin) plays a role in making DNA. Vitamin B-12 also helps keep nerve cells and red blood cells healthy.

Vitamin B-12 Uses

Vitamin B-12 has been looked at as a treatment for many diseases and conditions. These include fatigue, Alzheimer’s disease, heart disease, breast cancer, high cholesterol, and sickle cell disease. However, the results have been inconclusive. Studies suggest that vitamin B-12 does not help with stroke risk or lung cancer.

Vitamin B-12 supplements do help people who have an actual deficiency. Low levels of vitamin B-12 are more likely in people over 50. Vitamin B-12 is also more common in those with certain conditions, like digestive problems and some types of anemia. Low vitamin B-12 can cause fatigue, weakness, memory loss, and other problems with the nervous system.

Strict vegetarians are at risk for vitamin B-12 deficiency. Pregnant women and mothers who are vegetarian should talk to a doctor about vitamin B-12 supplements. If infants don’t get enough vitamin B-12, they can suffer lasting neurologic harm.

Vitamin B-12 Dose & Instructions for Use

The recommended dietary allowance (RDA) includes the vitamin B-12 you get from both food and any supplements you take.

Even at high doses, vitamin B-12 seems fairly safe. Experts have not found a specific dose of vitamin B-12 that’s dangerous. No tolerable upper intake levels have been set.

Vitamin B-12 Food Sources

Some good food sources of vitamin B-12 are:

• Fish and shellfish
• Meats
• Poultry and eggs
• Dairy products
• Fortified cereals

Generally, it’s best to get vitamins from whole foods. But doctors often suggest fortified foods -- and supplements -- to people over 50. As we age, it’s harder for our bodies to absorb vitamin B-12 from food.

Vitamin B-12 Supplement Information

Vitamin B-12 comes in tablets, capsules, and other forms, including under the tongue. It’s standard in multivitamins. Doctors can also give it by injection. Like any supplement, keep vitamin B-12 supplements in a cool, dry place, away from humidity and direct sunlight.

Vitamin B-12 Warnings

• Side effects and risks. Taken at normal doses, side effects are rare. High doses may cause acne. Allergies to vitamin B-12 supplements have been reported and can cause swelling, itchy skin, and shock.  
• Interactions. Drugs for acid reflux, diabetes, and other conditions may make it harder for your body to absorb vitamin B-12.