The Effect of Vitamin D on Calcium Retentions

Six young college women were given a well-selected basal diet supplemented daily by 250, 500, and 750 cc. of milk, respectively, for each of three collection periods of 10 days each. Subsequently, corresponding diets supplemented by approximately 500 I.U. of vitamin D were given to one of the subjects for one 10-day period and to the other five subjects for three 10-day periods each. At mean daily calcium intake levels of less than 0.8 gm., no evidence was shown of improved calcium retention with vitamin D. At mean daily calcium intake levels of 0.8 gm. and above, there was some evidence of improved retention with vitamin D, but the improvement was so slight that it was not statistically significant. Although for one of the five subjects the mean retention figures improved during each of the vitamin D periods, the difference between the two mean retention figures was not significant. It is concluded that the addition of approximately 500 I.U. of vitamin D to diets which were well-selected had little influence upon the calcium retention, and that the well-selected diet provides for the vitamin D needs of the young adult.