Influence of zinc and iron on dietary fluoride utilization in the rat.

Two experiments were conducted with the weanling rat fed a purified diet to determine the influence of dietary zinc (6, 30, 150 ppm) and iron (7, 35, 175 ppm) on fluoride bioavailability. Dietary fluoride in each case was 2 or 10 ppm as sodium fluoride. During a 6-wk trial, neither divalent zinc nor divalent iron affected fluoride bioavailability based on skeletal uptake of fluoride. Our studies were specifically designed to provide concepts about the effects of dietary trace element supplementation practices on dietary fluoride bioavailability especially in terms of fluoride originating from foods prepared in fluoridated water. Our results suggest that either iron or zinc can be added to foods to improve nutritional value without compromising the availability of food fluoride.