Enhancement of Fluoride Retention by Low Dietary Chloride without Manifestation of Chloride Deficiency in the Rat

Weanling male albino rats were fed a purified diet containing 10 ppm fluoride as sodium fluoride and 0.02, 0.04, 0.06, 0.08, or 0.10% chloride as sodium chloride for 6 wk. Food intake was unaffected by the level of dietary chloride. Rats fed diets containing either 0.02 or 0.04% chloride had significantly higher fluoride retention and skeletal uptake of fluoride than did rats fed higher chloride levels. Diets, however, had to contain 0.04% chloride or more to support normal weight gain, femur ash weight and plasma chloride concentration. The ability to enhance fluoride content of bone on a low chloride diet without undesirable effects of chloride deficiency may have important implications, since fluoride is thought to play a role in strengthening the mineral apatite structure of bone.