Grilling meat is a warm-weather tradition in America, especially on Memorial Day weekend. It's also an ancient human tradition, uniting friends and family around food and fire as long as our species has existed. Unfortunately, it also unites us around chemicals that can cause cancer.

Warnings like that can make it seem like scientists ruin everything — they already took sitting, late-night snacks and fireworks from us. But science works both ways, and now it has found at least a partial solution for this carnivore's conundrum. According to a recent study, published in the Journal of Agricultural and Food Chemistry, the secret to safer grilling has been under our noses all along.

Beer is a common ingredient at backyard cookouts, usually as a beverage. But research suggests marinating meat with beer, particularly dark beer, can curb the creation of polycyclic aromatic hydrocarbons (PAHs). These carcinogenic chemicals form as fat and juices drip from meat onto flames or embers, which then send smoky PAHs wafting up to coat the surface of our food.

PAHs can exist in more than 100 different combinations, some of which are found in known toxic cocktails like cigarette smoke and car exhaust. These chemicals have caused tumors, birth defects and reproductive problems in lab animals, according to the U.S. EPA, but the same effects have not been seen in humans. The National Cancer Institute says PAHs "become capable of damaging DNA only after they are metabolized by specific enzymes in the body." Nonetheless, health concerns raised in a 2002 report have led the European Union to set safety standards for PAHs in food.

dark beer

Marinating pork in dark beer for four hours reduced PAH levels by 53 percent, researchers say. (Photo: Shutterstock)

Previous studies have shown that beer, wine, tea and rosemary marinades can reduce carcinogens in cooked meat, but until now little was known about how various beer styles affect this phenomenon. And according to the recent study, the kind of beer seems to make a pretty significant difference.

To reach that conclusion, the researchers marinated pork for four hours in one of three beer types: regular pilsner, non-alcoholic pilsner or black beer. They then grilled the pork to well-done on a charcoal grill and tested its PAH levels. Black beer had the most dramatic effect, reducing eight major PAHs to less than half the amount found in unmarinated grilled pork. (The researchers chose eight PAHs that are identified by the EU as "suitable indicators for carcinogenic potency of PAHs in food.")

The two pilsners also showed an "inhibitory effect" on PAHs, but not as much. The regular pilsner suppressed PAHs by 13 percent, and the non-alcoholic variety went slightly further with 25 percent.

"Thus, the intake of beer-marinated meat can be a suitable mitigation strategy," the researchers say.

The study's authors aren't sure why beer marinade has this effect, or why dark beer fights PAHs better than pilsner does. It isn't the alcohol, since non-alcoholic pilsner nearly doubled the PAH suppression of its boozier relative. They suspect it might be antioxidant compounds in beer, especially darker beers, since antioxidants could restrict the movement of free radicals that are required for PAH formation. More research will be needed to know for sure, but this theory could help explain why antioxidant-rich red wine, green tea and rosemary extracts also keep carcinogens in check.

Whatever you use, the American Institute for Cancer Research already recommends marinating meat for at least 30 minutes to limit both PAHs and heterocyclic amines (HCAs), another type of chemical compound that can damage DNA. It also suggests grilling fish and poultry more often than red meat or processed meats like hot dogs, which can increase the risk for certain cancers. Reducing temperature, time on the grill and smoke exposure are other options for limiting cancer risk.

And while it can't take the place of a juicy, beer-marinated pork chop, there's also another, even more surefire way to cut back your risk: Save some room on the grill for fruits, vegetables and mushrooms.

Russell McLendon is science editor at MNN. Follow him on Twitter and Google+.

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