& Joannie Dobbs Wednesday,
B-12 shortage can affect your
Have you misplaced your keys lately or forgotten where you parked your car? Well join the club. This is not unusual. However, if your long-term memory is as good as ever, but you find it harder and harder to learn even simple things, then maybe it is time to have your vitamin B-12 status checked.
B-12 deficiency can result in a dementia similar to the early stages of Alzheimer's disease. Typical symptoms include loss of short-term memory and problems with orientation, even in familiar places. These symptoms are also associated with abnormal sensations in hands and feet.
Vitamin B-12 deficiency is most common in the elderly with up to 15 percent of this population being affected. And although diet is usually blamed as the culprit, animal foods such as meats, milk, and eggs contain enough B-12 to meet a persons requirements. The real reasons for this nutrient deficiency have more to do with how the body digests and absorbs B-12.
Vitamin B-12 in foods is tightly bound to protein. Stomach acid is required to free B-12 and make it available for absorption. Stomach acid may become too low due to: 1) aging which can naturally reduce stomach acid, and 2) antacids and other medications taken to decrease stomach acid secretion. In either case, B-12 absorption may be decreased.
If you are taking medication to control stomach acid, adding vitamin B-12 to your daily supplement is recommended by B-12 researchers. The supplement form is not protein-bound and is absorbed more normally when stomach acid production is low.
A second stomach problem can cause a B-12 deficiency. The normal stomach produces a substance called intrinsic factor. This factor is required for normal B-12 absorption. If an individual stops producing intrinsic factor, then taking B-12 supplements will not help. Monthly injections of the vitamin are recommended.
Research indicates more than 30 percent of people over 60 years of age (and 50 percent of those over 70) produce inadequate stomach acid for normal B-12 absorption. Because the liver can store enough B-12 to last a person as long as 10 years, inadequate intake of the vitamin or impaired absorption may not be obvious form ore than a decade.
Another reason to take B-12 seriously is the recent research that indicates those with low blood levels of vitamin B-12 are four times more likely to develop Alzheimer's disease than those with normal levels. It is not known if development of Alzheimer's induces low B-12 levels or the deficiency is responsible for onset of the disease.
If vitamin B-12 deficiency is detected within the first year or so, most symptoms are reversible. If not caught early, changes in mental function can be irreversible. However, B-12 therapy may halt the decline.
Common B-12 blood tests are notoriously inaccurate as a measure of B-12 deficiency. Consequently, other tests are needed to confirm questionable B-12 status. These test include measuring compounds that accumulate in the blood when there is too little B-12 in the body. High levels of methylmalonic acid in the blood or urine can indicate a B-12 problem.
Should you ask to have your B-12 status checked? If you are having either short-term memory problems or decreased sensations in your hands and feet, or if you are taking folic acid supplements that can mask the symptoms of a B-12 deficiency, then don't hesitate to get B-12 checked.
If you know that your parents or grandparents had B-12 problems, then periodically checking B-12 values may prevent problems later.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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