To many meat-lovers there is nothing more tantalizing than a juicy flame-broiled steak. Barbequing, grilling, frying, and broiling are all popular ways of cooking various types of meat in the home and at restaurants.For several years, reliable research has existed that links a chemical produced when meat (and fish) are cooked at very high temperatures and cancer in laboratory animals. Although no conclusive finding has been made as to its carcinogenicity in humans, the suspicion is that a similar link exists.
The compound known as PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) was tested for carcinogenicity in one experiment in mice and in two experiments in rats by oral administration in the diet.
It increased the incidence of lymphomas in mice of each sex. In rats, it produced adenocarcinomas of the small and large intestine in males and mammary adenocarcinomas in females.
When PhIP was administered to newborn male mice by intraperitoneal injection, there was an increased incidence of hepatic adenomas.
The compound has now been found to also initiate and promote prostate cancer in rats. This finding was made in connection with a study at Johns Hopkins Kimmel Cancer Center that was presented at the most recent meeting of the American Association for Cancer Research.
Prior research involving rats had indicated that PhIP causes early prostate cancer lesions in the ventral lobe (front) of the prostate but not in other lobes. The current study was designed to explore why this occurred.
PhIP was added to food given to a group of rats for up to eight weeks. After that, the researchers examined the ratsÃ¢â‚¬â„¢ prostates, intestines, and spleens for genetic mutations.
The team found that, after four weeks, all lobes had significantly higher mutations compared to rats that ate regular food. After eight weeks, the research there was a significant increase in proliferations only in the ventral lobe. This demonstrated that PhIP caused additional Ã¢â‚¬Å“promotionalÃ¢â‚¬Â events only in that lobe.
An increase in inflammatory mast cells and macrophages was observed in that lobe only. These findings suggest that these cells may contribute to the development of prostate cancer.
As with previous findings, however, this new rat-based data cannot be directly linked to humans since PhIP production varies widely depending on cooking conditions.