Plasma 25-hydroxyvitamin D responses of younger and older men to three weeks of supplementation with 1800 IU/day of vitamin D.

OBJECTIVE: The objective of this study was to compare changes in plasma 25-hydroxyvitamin D (25(OH)D) levels of younger and older men after three weeks of oral vitamin D supplementation. METHODS: Nine younger men (22 to 28 years) and nine older men (65 to 73 years) with self-reported vitamin D intakes below 200 IU/d were enrolled in February and randomized to 1800 IU/d of ergocalciferol (vitamin D2, n=11) or to a control group (n=7) and followed for three weeks. Blood was collected at baseline, and after one, two and three weeks for measurement of plasma concentrations of total 25(OH)D, 25(OH)D2 and 25(OH)D3. RESULTS: In both the younger and older supplemented men, 25(OH)D2 and total 25(OH)D concentrations increased significantly during the study, whereas values of these metabolites did not change in younger or older control subjects. No group showed significant changes in 25-hydroxyvitamin D3. There was a significant interaction between age group and supplement group, suggesting that the effect of vitamin D2 supplementation on changes in 25(OH)D2 changes with age. The mean increase in 25(OH)D2 was greater in the younger supplemented men than in the older supplemented men (37+/-9 nmol/L vs. 19.5 nmol/L, p=0.027), and this accounted for their significantly greater increase in total 25(OH)D. CONCLUSION: These data are consistent with an age-related decline in the absorption, transport or liver hydroxylation of orally-consumed vitamin D.

Acute myopathy associated with chronic licorice ingestion: reversible loss of myoadenylate deaminase activity.

A patient with acute rhabdomyolysis and absence of myoadenylate deaminase (MADA) associated with chronic licorice intoxication is presented. Clinical and laboratory examination of the patient and morphologic study over skeletal muscle were performed. The major effect of licorice intoxication is hypokalemia, which may explain most of the observed clinical symptoms and morphological changes. The absence of MADA may be a consequence of the direct toxic effect of licorice glycosides. To our knowledge, this is the first report in which a lack of MADA and chronic licorice intoxication has been shown to be associated with clinical, histochemical, biochemical, and morphological changes, which were completely reversed with potassium supplementation and licorice withdrawal.