The A list of B12 foods

B12 works alone and with other B vitamins to support many vital functions. Here's how to make sure you get enough.

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Most healthy adults get sufficient B12 from their regular diet. However, it's common for older people to have some level of B12 deficiency. This might stem from not including enough vitamin B12 foods in their diets or from age-related reduction in stomach acid, which the body needs in order to absorb B12 from food.

Certain conditions (such as Crohn's disease, pancreatic disease, and diabetes) and drugs (such as heartburn medication, which reduces stomach acid) also can interfere with absorption and increase your risk of deficiency. Vegans and vegetarians sometimes have trouble consuming enough B12, since many food sources are animal products.

Vitamin B12, like all B vitamins, is water-soluble, which means the body expels what it does not use. Its main job is to maintain healthy nerve cells, support proper brain function, and assist in the production of DNA and RNA.

B12 also works with other B vitamins to improve certain functions. For instance, B12 and folate (B9) together help to make red blood cells. 

Low levels of B12 can cause fatigue, nervousness, dizziness, numbness, and tingling in the fingers and toes. Severe, long-term deficiency may lead to loss of mobility, problems walking, or memory loss. A blood test from your doctor can measure B12 levels, and a serious deficiency can be corrected with B12 shots or high-dose supplements.

Yet, your diet is the best way to get B12. The average adult should consume 2.4 micrograms (mcg) of vitamin B12 a day, according to the National Institutes of Health. The table above shows some of the best vitamin b12 food sources.