Calcium phosphate metabolism showing the prevention of rickets by feeding clear grades of flour

Abstract

In the milling of flour the ideal seems to have been production of the whitest possible patent flour for human consumption, and the clear grades of flour, although they contain no shorts or bran, are too yellow in color for the American market. They contain much more phosphate than patent flour. The grain itself varies in phosphate content. Lack of available phosphate in the soil, or certain climatic conditions, may cause a reduction of phosphate content of grain. D. C. Mebane and myself showed that on a diet containing 45 per cent. of low phosphate rye (grown on peat soil) rickets was produced in white rats, whereas if this was substituted by high phosphate rye (from peat land in which the soil phosphate was made available by burning) no rickets developed. Soft winter wheat from the Ohio valley may be low in phosphate, and patent flour made from this wheat may contain as low as 0.075 per cent. P. Such flour was used in making a diet for white rats and produced severe rickets, whereas patent flour from hard spring wheat produced milder rickets, and Graham flour, no rickets. The percentage of phosphate in the patent flour depends, however, on the process of milling. At the Minnesota State Flour Mill some patent flour was made from the third middlings and contained 0.072 per cent. P, whereas the second clear flour contained 0.297 per cent. P. This, together with Graham flour, which I made by grinding hard winter tempered wheat containing 3.55 per cent. P, was used in making the following diets: Diet 96—NaCl 2 per cent., plaster of paris 2 per cent., yeast 1 per cent., spinach 1 per cent., lactalbumin 10 per cent., cotton seed oil 20 per cent., low phosphate flour 54 per cent., NaHCO₃ 10 per cent. Diet 98 was the same except there was no NaHCO₃ and the flour was 64 per cent. Diet 99 was the same as diet 98 except the second clear flour was used. Diet 100 was the same except that Graham flour was used.