Amino acid-restricted diets in the treatment of mammary adenocarcinoma in mice

The effect of a diet moderately restricted in tryptophan on the tumor and the nutritional status of C3H mice bearing mammary adenocarcinoma was examined. Five groups of female tumor-bearing mice were fed ad libitum a diet containing 1) 15% casein, 2) 15% amino acid mixture, 3) 15% amino acid mixture restricted in tryptophan 4) 15% zein supplemented with lysine and tryptophan or 5) 15% zein supplemented with lysine and restricted in tryptophan. Another group of tumor-free mice of similar age fed 15% casein served as a control for the tumor-bearing group fed the 15% casein diet. Moderate restriction of tryptophan in the diet appeared to have no effect on the tumor status of the animal. Tumor burden usually induced malnutrition in the animal. However, tryptophan restriction did not further aggravate this malnutrition. The source of protein, whether casein, amino acid mixture or zein, appeared to make a difference in nutritional status of tumor-bearing animals though not in tumor status. Casein-fed animals generally tended to have higher values for all the nutritional markers studied than did animals fed the amino acid mixture or zein.