Does growth require preformed carbohydrate in the diet?

Abstract

Carbohydrates are ordinarily regarded as indispensable components of the food intake. This belief is based on the presence of more or less carbohydrate in the food mixtures consumed by man and the higher animals, and the fact that sugar is a constant constituent of the blood. Furthermore, it has been concluded that carbohydrates are essential for the proper metabolism of the fats because ketone substances may be excreted in diabetes when sugar fails to be burned up in the normal manner in the organism.

We have found that rats receiving a diet in which the amount of digestible carbohydrate was at most exceedingly small can grow from an early age to adult size. The rations which we fed included protein—casein, edestin, or lean beef which had been thoroughly extracted with boiling water—inorganic salts, agar-agar, lard, butter fat and 0.4 gm. daily of dried brewery yeast furnishing vitamin B. The yeast can scarcely be regarded as a significant source of available carbohydrate. Success was likewise attained in experiments in which no agar-agar was introduced. In the latter case the only obvious sources of preformed carbohydrate were the yeast employed and such carbohydrate impurities as might still adhere to the protein preparation fed.