& Joannie Dobbs Monday, July 4, 2005
Age plays crucial role in B-12 needs
IF you are older than 70, you might need more than 100 times the 6 micrograms of vitamin B-12 typically found in a multivitamin, according to a recent study published in the Archives of Internal Medicine.
This is an extremely important study because B-12 deficiency is one of the most common nutritional problems in older people. The body's ability to absorb B-12 from often declines with age.
If you are under 70, B-12 could still be a concern. Heartburn drugs commonly used by middle-agers can decrease B-12 absorption. Poor B-12 status has been linked to increased risks of osteoporosis and cardiovascular disease.
Question: How common is B-12 deficiency?
Answer: It has been estimated that 1 out of 7 people over age 65 do not absorb B-12 normally and thus could develop a deficiency even when diet or supplements contain sufficient B-12.
Q: What are the signs of a deficiency?
A: The liver can store significant amounts of B-12, so it might take months or years for a deficiency to develop. Symptoms can sneak up on people and take many forms, as both nerves and red blood cells are affected. The result can be memory problems, depression or other psychiatric problems, and symptoms related to gradual damage to the nervous system. The condition can even be mistaken for Alzheimer's disease.
Q: How is it treated?
A: The standard treatment is monthly injections of the vitamin for the rest of a person's life. But medical scientists have been debating the efficacy of high doses of B-12 because about 1 percent of the vitamin in supplements is still absorbed by those with absorption problems. Some studies indicate that a daily dose of 1,000 to 2,000 micrograms can be as good as injections, but none of the studies established if lower doses were as effective.
Q: What dose of supplements is needed to treat a deficiency?
A: In the Archives of Internal Medicine study, Dutch researchers evaluated the effects of five different doses of B-12 using 120 people over the age of 70 whose blood values indicated a deficiency. After 16 weeks it was found that the dose required to most effectively normalize B-12 status was from about 650 to slightly more than 1,000 micrograms per day.
Q: Are high doses dangerous?
A: There are no reports of adverse effects due to high doses.
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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