Some Results of Feeding Rats a Human Diet Low in Thiamine and Riboflavin

Abstract

This report covers some of the results of a study of feeding white rats a human diet, composed of foods commonly appearing on American tables, wherein the thiamine and riboflavin contents were low. Five diets, differing from one another only in the flours from which the bread component was made, were prepared. Supplementations of patent white flour with thiamine, riboflavin and niacin, while improving the growth rate of the rats, were not adequate to secure weights attained by animals eating the diet that contained whole wheat flour. The addition of thiamine to the flour increased the daily caloric intake from 26.8 to 40.0 and yet the average gain of weight was less than 1 gm. per day for the period when the intakes of food and water were tested. The low daily intake of riboflavin was inadequate for satisfactory growth. The addition of both thiamine and riboflavin to the diet prevented the hypochromic anemia which developed among rats which ate either diet E or diet F. Essentially normal blood values were obtained by fortification of the flour with these two vitamins as well as by the diet which contained the whole wheat flour. Peripheral necrosis associated with mild fatty degeneration occurred in the livers of all animals eating diet E. Cirrhosis did not develop. The addition of thiamine and riboflavin appeared to prevent extensive necrosis but the livers of rats eating the diet that contained whole wheat flour had a more nearly normal cellular organization than those of rats to whose diet thiamine and riboflavin were added. The thyroid glands of all animals were hyperplastic. Mitotic figures were common in the acini of the thyroids of animals eating diet G. Extensive cellular activity was demonstrated even in animals eating diet J. These changes may be due, not to any lack of vitamins or to inadequacy of iodine, but perhaps to some dietary imbalance. Changes from the normal in the percentage distribution of cells in the pituitaries were observed in these animals. These changes constituted relative increases of the percentages of chromophobes and corresponding decreases of the percentages of acidophils. Chemical analyses of the concentrations of thiamine and riboflavin of the livers, skeletal muscles, kidneys and testes of animals eating diet E were made. These values showed excessively low concentrations of these vitamins in the tissues analyzed. They compared favorably with such data assembled elsewhere. Fortification of the flour used in the bread component of the low thiamine-low riboflavin human diets with thiamine, riboflavin and niacin in the amounts indicated proved inadequate to promote satisfactory growth or to prevent pathologic changes in the livers, thryroids and pituitary glands of white rats.