The smell of food grilling is a hallmark of summertime fun—but the quintessential cooking method may not be the best option for your health, experts warn.
When meat is cooked at high temperatures or directly over an open flame, harmful chemicals can form. Two in particular—heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs)—have been linked to serious disease.
“Both HCAs and PAHs are considered potential carcinogens, meaning they may increase the risk of cancer,” Darin Detwiler, PhD, author, consultant, and professor of food policy at the Northeastern University College of Professional Studies, told Health.
However, that doesn’t necessarily mean that the occasional barbecue is detrimental to your health, experts said.
Here’s what to know about how HCAs and PAHs can affect your body and how to ensure you’re grilling safely this summer.
The two harmful chemicals associated with grilling can form naturally when muscle meats—including beef, pork, fish, or poultry—are cooked at very high temperatures or over an open flame.
The formation of HCAs increases with higher temperatures and longer cooking times. Grilled or barbecued chicken or steak have high concentrations of HCAs, for example.
While HCAs are created from reactions within the meat itself, PAHs develop slightly differently—when fat and juices from meat fall onto an open flame, they create smoke, which deposits the PAH chemical onto the surface of the meat. PAHs are also found in cigarette smoke and car exhaust.
“When consumed, these chemicals can be metabolized by the body into compounds that can damage DNA, potentially leading to cancer,” explained Detwiler.
The highest levels of HCAs and PAHs are found in grilled meats, but other foods—including grilled vegetables, bread, and even roasted marshmallows—can also form PAHs when they are charred and exposed to smoke, said Detwiler.
“The risk is generally lower compared to meat, but it is still present,” he said.
More research is needed to determine who might be at a greater risk of health effects from exposure to HCAs and PAHs. But Detwiler said the following are considerations:
- Genetics. Some people may have genetic variations that affect how their bodies process and detoxify HCAs and PAHs, making them more susceptible to the harmful effects.
- Existing health conditions. People with compromised immune systems, such as those with cancer or diabetes, may be more vulnerable to the potential health risks associated with these chemicals.
- Age and lifestyle factors. Older adults and those with poor dietary habits or lifestyles may also be at greater risk.
In addition to HCA and PAH exposure, grilling might also be a riskier cooking method because of the meat people typically barbecue.
Processed meats—including grilling staples such as hot dogs and sausages—are “carcinogenic to humans,” the International Agency for Research on Cancer said in 2015. The organization also deemed red meat “probably carcinogenic to humans.” This was unrelated to how the meat was cooked.
Despite concerns about grilling being linked to the formation of carcinogens, there’s not enough concrete evidence to say that grilling can definitively raise the risk of cancer in humans.
Past studies have used questionnaires to look at the meat people eat and how they prepare it—researchers found that high consumption of well-done, fried, or barbecued meats was associated with increased risks of colorectal, pancreatic, and prostate cancer.
Other studies have also found that animals fed diets high in PAHs and HCAs developed a variety of cancerous tumors.
However, other studies found no association between HCAs and the risk of colorectal or prostate cancer.
The difference could come down to how frequently a person is exposed to these chemicals. Like other carcinogens, the risk of cancer rises with repeated exposure to HCAs and PAHs, said Marion Nestle, PhD, MPH, author and visiting professor of nutritional sciences at Cornell University.
“The risk of one exposure is extremely small,” she told Health.
In addition to HCAs and PAHs, people can be exposed to other chemicals while cooking, Detwiler said.
For one, the chemical acrylamide can form in certain foods during high-temperature cooking processes, such as frying, roasting, and baking, he explained. While it is not typically associated with charred meat, acrylamide is more commonly found in starchy foods or grains such as fried potatoes or toasted bread.
“Acrylamide is a chemical [that] forms from sugars and an amino acid (asparagine) that are naturally present in food,” said Detwiler. “It is considered a potential carcinogen and has been linked to an increased risk of cancer.”
The National Toxicology Program at the National Institutes of Health and the World Health Organization Expert Committee on Food Additives consider acrylamide to be a human health concern. The chemical has been shown to cause cancer in animals exposed to very high doses, but there is no evidence that it causes cancer in humans.
According to the Food and Drug Administration (FDA), there are other chemicals can form during cooking too, including furan and 4-methylimidazole. These have also been associated with cancer in rodents, though they seem to be safe in humans.
Though grilling could raise your exposure to harmful chemicals, there are things you can do to make it safer.
As with everything else in nutrition, it’s best to eat grilled foods in moderation, Nestle said. But when you do barbecue, use a gas grill, added Devin Alexander, a chef and author based in Southern California.
“Gas burns cleaner and emits fewer particulates, so opt for a gas grill over charcoal,” she told Health.
To get rid of charred food residue, it’s also important to clean your grill frequently.
Changes to your normal grilling habits or the foods you barbecue can also help reduce your chemical exposure:
- Prevent flare-ups. To avoid grease drips from falling onto hot coals or flames, trim excess fat from meat. You can also use aluminum foil to create a barrier between the food and the flames, reducing smoke (and PAH formation).
- Choose lean cuts. “Fatty meats produce more smoke and potentially harmful compounds,” said Alexander. “So opt for lean cuts to minimize emissions.”
- Avoid overcooking. To reduce exposure to high temperatures, consider precooking meat in the microwave or oven and then grilling it to a safe internal temperature, Detwiler said.
- Prevent burning. To prevent charring or burning, Detwiler recommends flipping meat frequently. “If parts of the food become charred, cut those parts away before eating,” he added.
- Eat more veggies. Because vegetables generally form fewer HCAs and PAHs as compared to meat, said Detwiler, “incorporate more grilled vegetables into your meals.”
By understanding and mitigating the risks associated with grilling, it’s possible to enjoy grilled foods while protecting your health, he added.
“Focus on minimizing exposure to these compounds by using safer cooking practices,” Detwiler said.