Oral versus intramuscular vitamin supplementation for hypovitaminosis in the elderly.

Thiamin, folate, biotin, riboflavin, nicotinates, pantothenate, carotenes, and vitamins B6, B12, A, E and C were measured in the blood of 228 elderly ambulatory residents of a nursing home. Their mean age was 87 years (range, 60-102). None had undergone major surgical procedures; their diet was good, and each had received at least one multivitamin pill every day for 3 to 5 months before the study. A comparison group of 204 healthy volunteers, aged 20-50 was also studied. Of the 228 elderly subjects, 88 (39 percent) showed vitamin deficits despite oral vitamin supplementation. Single and multiple deficits of vitamin B6, nicotinate, vitamin B12, folate, and thiamin were found. Three months after a single intramuscular injection of multivitamins (with no other vitamin supplementation), these deficits were no longer detectable in the blood of 89-100 percent of the vitamin-deficient elderly. Intramuscular rather than oral vitamin supplementation is a more effective method for maintaining adequate blood levels of vitamins in the elderly; the intramuscualr route apparently promotes saturation of tissue stores with enough vitamins to meet the needs, and thus obviates problems of vitamin malabsorption possibly due to drug interference or small-bowel atrophy.