Should I take a vitamin B12 supplement? I'm 68 and in good health.
Vitamin B12 deficiency is rare, but older people may, in fact, benefit from taking a supplement. First -- even though you're in good health — you may want to discuss this with your doctor to be sure it's a good idea for you, especially considering any other supplements or medications you may be taking.
The body uses vitamin B12 to make DNA and to keep nerve cells and red blood cells healthy. Many foods contain vitamin B12, but it's primarily found in animal products, meat, poultry, eggs, milk and other dairy foods. Although B12 is a water-soluble vitamin, the body can store several years' worth of it, so most people maintain healthy levels.
However, research is indicating that B12 deficiency in older people is more common than once believed. That may have something to do with a lower amount of stomach acid in older people. In food, vitamin B12 is found within protein, and hydrochloric acid in the stomach is needed to unleash the vitamin from the protein. Older people tend to have less stomach acid, so taking a supplement might be helpful. In a supplement, the vitamin isn't bound to a protein, so stomach acid isn't needed to make it available to the bloodstream.
There is a growing body of evidence that vitamin B12 deficiency -- possibly even a slight deficiency -- is linked with shakiness, muscle weakness, incontinence, vision problems, mood disturbances, and even dementia. In fact, a study 84 subjects over age 69, reported in the December 2006 issue of the American Journal of Clinical Nutrition, found a strong association between vitamin B12 deficiency and decreased cognitive function, especially regarding language comprehension and expression.
Vitamin B12 deficiency is also more common in strict vegans who don't eat animal protein, and in people with a disease called pernicious anemia, in which a person lacks a substance called "intrinsic factor," or IF, which moves B12 from the intestinal tract into the bloodstream.
The recommended dietary allowance for adults is 2.4 micrograms a day. You can get this amount over the course of the day by eating a cup of plain low-fat yogurt, a hard-boiled egg and a chicken breast. Or, you can get it all at breakfast, for example, with one cup of milk with one cup of raisin bran. Many authorities recommend people 50 and older to take a daily supplement with as much as 25 to 100 micrograms of vitamin B12 to maintain healthy vitamin B12 levels.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or firstname.lastname@example.org.
This column was reviewed by Jaime Foster, registered dietitian and program specialist for Ohio State University Extension in the Department of Human Nutrition, College of Education and Human Ecology.
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