Sizzling burgers, grill-marked juicy steaks and barbecued spareribs are summertime favourites for many people.
However, studies linking barbecued meat to cancer might have you wondering if eating grilled meat is harmful. And if so, how much is too much?
Here’s what the science says about the grilled meat-cancer connection, plus tips to make it safer.
What’s the harm with grilled meat?
The concern revolves around two chemicals formed during grilling: heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Once consumed, enzymes in the body metabolize HCAs and PAHs into compounds that can damage DNA in cells, which could potentially increase the risk of cancer.
HCAs are created when protein in meat, chicken and fish reacts with creatine, a natural compound in muscle meats, during high-heat cooking (for example, grilling, barbecuing, broiling, pan-frying, deep-frying).
PAHs form when fat and juice from meat drip into the grill grate or onto hot coals, causing flames; PAHs are carried up in the smoke and stick to the surface of the meat. PAHs are also present in smoked meat.
The longer you grill meat, the more HCAs and PAHs are formed.
Exposure to HCAs and PAHs causes cancer in rodents. Keep in mind, though, that the doses of HCAs and PAHs used in animal studies were very high, far higher than the amount a person would consume in a typical diet.
Does eating grilled meat cause cancer in people?
There’s no conclusive data that it does. Findings from observational studies, which don’t prove cause and effect, have been mixed.
Some studies have associated a high intake of well-done, fried or barbecued meats with a greater risk of colorectal, pancreatic and prostate cancer. But other studies have not found a link.
It’s possible that diet questionnaires used in research studies don’t capture enough detail about cooking methods to accurately determine HCA and PAH levels and could, therefore, under or overestimate intake.
A person’s genetic makeup can also influence the potential risk of exposure to HCAs and PAHs. The activity of enzymes in the body that metabolize HCAs and PAHs, for example, varies from person to person.
How much grilled meat is too much?
Because of the lack of definitive evidence tying HCA and PAH consumption to cancer risk, there are no intake guidelines for grilled meat.
There are, however, intake recommendations for red meat and processed meats based on convincing evidence that high intakes of both increase the risk of colorectal cancer.
The Canadian Cancer Society advises limiting red meat (such as beef, lamb, pork, goat) to no more than three servings per week (one serving is equivalent to three ounces). Processed meats (such as ham, salami, bacon, hotdogs) should be consumed sparingly if at all.
Are grilled vegetables safe to eat?
Because vegetables contain little protein and don’t have any of the creatine that’s found in meat, grilling vegetables doesn’t create HCAs. Plus, vegetables (and fruit) contain flavonoids, phytochemicals thought to have anti-cancer properties.
Grilled tofu and bean burgers also don’t contain HCAs.
How can I reduce HCAs and PAHs in barbecued meat?
To reduce HCAs and PAHs, marinate meat for at least 30 minutes before grilling. Antioxidants in marinade ingredients such as wine, beer, citrus juice, herbs and spices are believed to inhibit HCA and PAH formation.
Marinades may also act as a barrier, shielding meat from PAHs carried up by smoke.
Choose lean cuts of meat (such as top sirloin, tenderloin, eye of round) and trim visible fat before grilling to help prevent flare-ups and smoke. Covering the grill with punctured aluminum foil will also prevent flare-ups.
Grill smaller cuts of meat such as kebabs instead of a whole steak to cut down on grilling time. Fish and seafood also take a shorter time to cook. Cook meat over a low flame to reduce HCAs and PAHs formation.
Partially precook (such as roast) large cuts of meat and then finish on the grill. Doing so has been shown to substantially reduce HCA formation.
Turning meat and burgers over frequently during grilling has also been shown to considerably reduce HCAs. Trim off charred bits on meat since these areas will have a higher concentration of HCAs.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD.
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