Effects of Feeding Sour Milk on Longevity and Tumorigenesis in Mice and Rats

Abstract

The effects of feeding sour milk on longevity, transplantable tumor , and chemically i nduced colon tumorigenesis were studied. (1) Female ICR mice were fed with pasteurized sour milk throughout their life. Mice given sour milk had a longer life span than those given the control diet, while the life span of those given whole milk was almost the same as those given the control diet. Necropsy showed that the main causes of death were tumors, renal atrophy, and pneumonia. to inhibit at least one of these diseases. (2) Female ICR mice were intraperitoneally inoculated with Ehrlich ascites tumor cells, and the effect of dietary sour milk on the growth of tumor cells was determined. Feeding pasteurized sour milk or pasteurized starter cells inhibited the growth of tumor cells. The inhibitory effect was dependent on the dose of the starter cells. These results suggested that some component(s) of starter cells was responsible for inhibition of tumor cell proliferation . (3) When male F344 rats were intraperitoneally injected with 1,2-dimethylhydrazine , the effect of dietary sour milk on the incidence of intestinal tumors induced was studied . While the number of colon tumors per animal in rats fed with artificially acidified milk or starter cells was not significantly different from that in rats fed with control diet, rats f ed with sour milk developed significantly fewer colon tumors . This finding indicates that sour milk inhibited 1,2-dimethylhydrazine-induced colon tumorigenesis in F344 rats.