Effect of Sodium Fluoride on Calcium Absorption and Balances in Man

Abstract

1) Calcium and phosphorus balances have been determined in nine patients under strictly controlled dietary conditions during a daily intake of an average of 20.6 mg sodium fluoride. Calcium 47 absorption studies were conducted in eight of these patients. 2) During sodium fluoride intake, the urinary calcium excretion of three of the nine patients was lower than in the control study. This decrease ranged from 15 to 30%. The fecal calcium excretions of the nine patients and the average calcium balances remained in a range similar to that in the control study. The phosphorus and nitrogen balances were similar in the experimental and control phases. 3) In the majority of patients the plasma levels of 47Ca were lower during the intake of sodium fluoride than in the control studies indicating decreased absorption of 47Ca. The average decrease of the 47Ca plasma levels was 30% and the average decrease in 47Ca absorption, determined from fecal 47Ca excretions, was 23%. 4) These studies have shown that the intestinal absorption of calcium and the calcium balances did not improve during an intake of 20.6 mg sodium fluoride/day given for 22–42 days.