WASHINGTON (Reuters) - A compound formed when meat is charred at high temperatures -- as in barbecue -- encourages the growth of prostate cancer in rats, researchers reported on Sunday.

Their study, presented at a meeting of the American Association for Cancer Research, may help explain the link between eating meat and a higher risk of prostate cancer.

It also fits in with other studies suggesting that cooking meat until it chars might cause cancer.

The compound, called PhIP, is formed when meat is cooked at very high temperatures, Dr. Angelo De Marzo and colleagues at Johns Hopkins University in Baltimore reported.

It appears to both initiate and promote the growth of prostate cancer in rats, they said.

"We stumbled across a new potential interaction between ingestion of cooked meat in the diet and cancer in the rat," De Marzo said in a statement.

"For humans, the biggest problem is that it's extremely difficult to tell how much PhIP you've ingested, since different amounts are formed depending on cooking conditions."

For the study, Yatsutomo Nakai and other members of De Marzo's team mixed PhIP into food given to rats for up to eight weeks, then studied the animals' prostates, intestines and spleens. They found genetic mutations in all the organs after four weeks.