by Carole Jackson, Bottom Line Health
We Americans love our grilled meat, fish and poultry, whether from the backyard or in a restaurant — especially those blackened morsels on the edges of, say, a sizzling burger or barbecued ribs. In fact, we continue to eat our grilled meat even though it was discovered over the past two decades that charring meat produces distinctive chemicals that may raise our risk for colon, prostate or breast cancer. Thatâs love, folks! But now a study shows that this cancer risk may be even higher than we thought… maybe high enough to finally take the sizzle out of our grilling habit. Letâs see…
WHAT THE NEW GRILLING STUDY FOUND
Researchers from the Norwegian Institute of Public Health were concerned that previous studies on charred foods could be misleading because the kind of mice used in the studies do not metabolize the potentially dangerous substances in the same way that humans do. To correct this problem, researchers genetically engineered a group of mice to more closely mimic a humanâs metabolism. (In particular, these mice were bred to have enzymes called sulfotransferases spread more widely within the digestive system, like humans have.)
Next, researchers injected a group of engineered mice and a control group of typical mice with a carcinogenic chemical called PhIP, which is formed in charred meats cooked at high temperatures — and the findings were dismaying. After 16 weeks, 31% of the typical mice had cancerous intestinal tumors — but in the engineered set, a whopping 80% did! In other words, the study concluded, humans may be more sensitive to the carcinogens found in charred meat than we previously thought.
AN EXPERT WEIGHS IN
To get perspective on the study, which was published in the October 17, 2011 issue of Molecular Carcinogenesis, I called molecular toxicologist Robert J. Turesky, PhD, research investigator at the Wadsworth Center, New York State Department of Health, in Albany. Dr. Turesky said that the study was interesting, but he thought that it is tenuous at best to extrapolate its findings to human risk. Among his reasons…
- The dosage of PhIP given to the animals was massive. Dr. Turesky said that it was “a million-fold, if not more” than humans would ever ingest per day.
- The mice received a PhIP compound that was not the natural form present in charred meat, but rather a synthetic chemical that is based on it.
- The researchers injected the chemical directly under the skin of the mice, which meant that the animals absorbed all of the chemical. When humans ingest PhIP, it is just one element in a complex mixture of many other chemicals, all of which influence how the body metabolizes and responds to compounds in foods — so humans donât usually absorb 100% of PhIP.
- The injections were given to pregnant female mice just before they gave birth and then to those baby mice in the weeks shortly after their birth — times when the mice were particularly sensitive to carcinogenic chemicals.
SHOULD WE WORRY MORE?
You may be wondering why the researchers “stacked the deck” so much in the way they designed the study — but in fact, there was a good reason for what they did. Their goal was to see whether they were right to be concerned that the sort of laboratory mice commonly used for toxicological research (as opposed to their mice engineered to be more like humans) could have skewed the results of previous studies. In that goal, they seem to have succeeded — and now scientists are going to have to go back to their labs and design new studies with these and other animal models to see just how dangerous to us our beloved grilled meat really is.
Meanwhile, as Dr. Turesky noted, these results donât mean that we should ignore the health issue altogether, because there is no doubt that charring meat can create human carcinogens. However, there are ways to minimize the formation of these chemicals in foods when you grill…
- Before grilling, marinate the food — even just 30 minutes is helpful — in marinades containing some combination of vinegar, lemon juice, tarragon, sage, mint and rosemary. There has been some evidence that this reduces the formation of carcinogens when grilling, though the data is still inconclusive, said Dr. Turesky.
- Flip meat on the grill frequently to minimize the burning of surfaces.
- Avoid eating well-done meat. The longer the meat is on the grill, the higher the possibility that PhIP will form.
- Eat lots of raw or lightly cooked vegetables with your meat. There is some evidence that cruciferous vegetables in particular (cabbage, broccoli, cauliflower, Brussels sprouts and others) are protective. They may change the way the body metabolizes chemicals produced by grilling and therefore cancel out at least some of the negative health effects of ingesting PhIP from cooked meats.
Now that Dr. Turesky has pointed out some of the shortcomings of the most recent study, I admit that I feel a little relieved. I know that frequently eating grilled meat isnât the best dietary choice, but Iâm not going to stop having the occasional grilled steak or chicken… and weâll see what future research tells us.
Robert J. Turesky, PhD, research investigator at the Wadsworth Center, New York State Department of Health, Albany, and associate professor, School of Public Health, University at Albany, University of New York.