Abstract
To clarify the effects of successive daily oral administration of a multivitamin preparation (200 IU/day of vitamin D_2) for 4 weeks on vitamin D nutritional status in elderly subjects, the plasma levels of 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25(OH)_2D), parathyroid hormone (PTH), calcium (Ca) and phosphorus (Pi) were determined. Although the plasma levels of 25-OH-D in the elderly subjects were very low before administration, these significantly increased to the normal range by successive administration of the preparation for 28 days. The levels did not significantly decrease even 8 days after the cessation of administration. The 1,25(OH)_2D levels in the elderly male which were low before administration increased to the normal range by the successive administration, while these in the elderly female within the normal range were not significantly changed by the administration. The results suggest that the metabolism of 25-OH-D to 2,25(OH)_2D was well controlled without showing hypervitaminosis. The initial high PTH levels in the elderly female decreased to the normal range by the administration. The plasma Ca and Pi levels were kept in the respective normal ranges during the experiment. These results suggest that successive daily oral administration of vitamin D is effective to improve the vitamin D nutritional status in the elderly subjects without hypervitaminosis.
