A New Low Fluorine Diet and Its Effect Upon the Rat

Abstract

Mineralized milk proved to be a good low fluorine diet through five generations of rats. Summer milk properly mineralized supported reproduction while winter milk was inferior in this respect. Fluorine is not necessary for the rat in amounts larger than the 0.1 to 0.2 p.p.m. found in milk. Thus 50 μg. of fluorine per kilogram of body weight per day meets all of the requirements of the rat for growth, reproduction and general well being. Additional fluorine from 0.1 to 20.0 p.p.m. caused no measureable improvement in the rat. The borderline zone for bleaching of the teeth occurred at a level of 10 p.p.m. Bleaching was not prevented by aluminum or the extra vitamin A furnished by percomorph oil used in these experiments. There was a placental transfer of fluorine even on the low level of fluorine ingested. This was not increased until the level of fluorine reached 10 p.p.m. thereafter there was a definite increase in fluorine passing through the placenta. Mammary secretion of fluorine, on the other hand, was not affected by as much as 20 p.p.m. The low level of fluorine furnished by the basal milk diet did not deplete the fluorine stores of the rat through five generations, nor did it increase the demand for fluorine. There was no cumulative fluorine effect carried over from generation to generation on either the lowest or the highest level. The fluorine normally present in milk appeared to have been less readily metabolized for storage in the skeleton than that added as sodium fluoride.