VITAMIN-B-12 DEFICIENCY IN THE ELDERLY - CURRENT DILEMMAS

Vitamin B-12 deficiency is present in up to 15% of the elderly populat ion as documented by elevated methylmalonic acid with or without eleva ted total homocysteine concentrations in combination with low or low-n ormal vitamin B-12 concentrations. Clinical signs and symptoms of vita min B-12 deficiency are insensitive in elderly subjects and comorbidit y in these subjects makes responses to therapy difficult to interpret. Many elderly subjects with hyperhomocysteinemia have undiagnosed vita min B-12 deficiency with elevated serum methylmalonic acid concentrati ons. Therefore, such elderly subjects should not receive folic acid su pplementation before their vitamin B-12 status is diagnosed. Oral vita min B-12 supplementation may be effective in lowering serum methylmalo nic acid values in the elderly. However, the dose of vitamin B-12 in m ost common multivitamin preparations is too low for this purpose. Rese arch efforts should be directed toward determining practical methods f or diagnosing and treating vitamin B-12 deficiency in the millions of elderly subjects with undiagnosed deficiency.