They conducted experiments on two groups of rats. Some of the rats from each group were injected with NMBA, a chemical carcinogen that induces esophageal cancer. NMBA is one of a group of chemicals called nitrosamines, compounds that have been linked to cancer. Nitrosamines are found in fried bacon, cured meats, tobacco products, beer and certain industrial products.
Rats in the study received NMBA and their diet in a variety of combinations. Some rats were fed a regular diet without raspberries, while others received diets consisting of 5 percent or 10 percent black raspberries. Some were fed raspberries only after receiving NMBA, while others were fed the raspberry diet before and after the injection with the carcinogen.
Feeding the rats 5 and 10 percent black raspberries before and after NMBA treatment reduced the number of tumors per rat by 39 and 49 percent, respectively, when compared to animals not fed black raspberries.
The fruit also hindered the development of esophageal cancer in
individual rats fed black raspberries after NMBA treatment. By
week 15 of the study, diets of 5 and 10 percent black
raspberries appeared to decrease tumor occurrence and size. At
week 25, diets
Contact: Gary Stoner
Ohio State University