EVIDENCE THAT BONE-RESORPTION OF YOUNG MEN IS NOT INCREASED BY HIGH DIETARY PHOSPHORUS OBTAINED FROM MILK AND CHEESE

Our study consisted of two 10-day periods. In period 1, seven young me n (22-31 yrs; average weight of 70 kg) were fed food items providing 8 00 mg P, 1200 mg Ca, 11.7 MJ and 14.5 g nitrogen. In period two, diet phosphorus was doubled to 1600 mg by addition of cheese and milk. Diet ary nitrogen and calcium were equalized for the two periods. Compariso n of period 2 with 1 showed that serum intact parathyroid hormone tend ed to increase suggestive of increased bone turnover, but this possibi lity was not supported by the bone resorption marker, urinary deoxypyr idinoline. High dietary phosphorus increased urinary ammonia N excreti on which may play a small role in the mechanism of the hypocalciuric e ffect of P. We conclude that the high phosphorus intake typical of man y diets does not promote bone resorption if the calcium to phosphorus ratio is <1:1.5.