Effect of low and high calcium intake on Sr 90 metabolism in adult man

Abstract

Balances of Sr 90 have been determined in man under constant dietary conditions during low and high calcium intake but during a similar intake of Sr 90. Ten patients were studied during low calcium intake (average 213 mg Ca/day) and 10 patients during high calcium intake (average 1718 mg Ca/day), the latter being attained by adding calcium gluconate tablets to the constant low calcium diet. The average Sr 90 intake was similar during low and high calcium intake, 4.6 pCi/day and 5.7 pCi/day, respectively. The average Sr 90 balance was slightly more negative during high calcium intake, −0.36 pCi/day, than during low calcium intake, −0.01 pCi/day, however this difference was not significant. Also, there was no significant difference between the percent net absorption of Sr 90 during the intake of the low and high calcium diet, 12.3 % versus 6.5% of the Sr 90 intake, respectively. The Sr 90/Ca ratios of the diet, urine and stool were determined and the Observed Ratios (O.R.) were calculated. The Sr 90/Ca ratios of stool/diet were less variable than the Sr 90/Ca ratios of urine/diet during the intake of different levels of calcium. Since the Sr 90/Ca ratio of stool was similar to the Sr 90/Ca ratio of the diet during both low and high calcium intake, the fecal Sr 90/Ca ratio can be used for the estimation of the dietary Sr 90 intake.