Fluoride Action Network


An investigation has been carried out on the effects of the intake of small amounts of sodium fluoride on kidney structure and function in rats, with a view to the possibility of establishing some means of testing for the toxic effects of fluorine in human beings, and of demonstrating the existence of a fluorine hazard before such severe intoxication has resulted as to cause disability and obvious skeletal lesions. The effects on kidney function are immediate.


Rats given small amounts of NaF in the diet exhibited, in addition to the well-known skeletal and dental lesions, marked polydipsia and polyuria,

… At autopsy the kidneys were dark, shrunken and nodulated.

Demonstration of alkaline phosphatase showed that there were fibrotic lesions in the cortex, where the enzyme was practically absent owing to absence of functional tubular tissue.

The histological examination indicated that in the kidneys there was a vascular, glomerular and more obviously tubular degeneration leading finally to interstitial fibrosis.

The fluoride-fed rats showed diminished growth, and at low body weights there was a marked diminution of fat stores.

Nitrogen metabolism was greater in the fluoride-fed rats than in the controls.