Submitted to: Cancer Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2001
Publication Date: N/A
Interpretive Summary: The incidence of certain cancers has traditionally been lower in populations who consumed soyfoods. The current study was conducted to determine if the incidence experimentally-induced colon cancer could be reduced by feeding rats a diet containing soy protein isolate. The data demonstrated a significant reduction in cancer of the colon in soy-fed rats, confirming the epidemiological data. This provides a basis to further study these effects by determining the mechanisms by which soy acts.
Technical Abstract: Male Sprague-Dawley rats (F2 generation) that have been fed modified American Institute of Nutrition-93G diets formulated with a single protein source of either casein or soy protein isolate for their entire life received azoxymethane once a week for 2 weeks (s.c., 15 mg/kg) starting at age 90 days. Forty weeks later, all rats were euthanized, the colon was examined visually for masses and these were subsequently evaluated histologically. Rats fed the casein diet had a 50% incidence of colon tumors compared with 12% on soy protein-based diets (P<0.05). These results suggest that consumption of soy protein-containing diets may reduce the risk of developing colon tumors.