For many, grilled foods like charred burgers, barbecues, hotdogs, and extra crispy veggies are mealtime favorites and a big part of summer fun. According to a survey, about 20% of the American respondents barbecue several times a month. Many said summer is incomplete without barbecuing, not only because of the tender taste of grilled meat but also because it allows them to spend quality time with family members and friends.
Unfortunately, during the grilling process, some chemicals are known to potentially cause cancer naturally develop in both meat and plant-based foods.
Chemicals found in grilled foods or foods cooked at high temperature
When cooking over high heat, especially on an open flame, two known carcinogenic substances are formed: heterocyclic aromatic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs).
HCAs naturally occur when the amino acids, sugars, and creatinine (muscle proteins) of meat such as beef, pork, chicken, and fish react to high temperatures, especially above 300 ºF. The longer the meat is exposed, the more of these substances are produced.
PAHs, on the other hand, form as a result of the fat and juice that drips into the coal, which then causes flames and smoke that contain the substance. The released PAHs then adhere to the surface of the meat being grilled. Aside from this, the person grilling the meat is also exposed to PAHs in smoke during the process. These are the same compounds found in cigarette smoke and car exhaust which are also linked to different cancers.
For vegetables and other plant-based foods, a different substance called acrylamide is developed during high-temperature cooking. This does not only include grilling but also during baking, roasting, and frying.
Can they cause cancer?
HCAs and PAHs are known carcinogens as they are capable of causing changes in the DNA of cells. As these two chemicals are metabolized in the body through enzymes, the process yields byproducts that can cause DNA damage and then lead to the development of cancer, according to research conducted by Robert Turesky of the University of Minnesota.
Studies involving animal models have shown the carcinogenic effects of these substances upon exposure. In many experiments, rodents fed with a diet containing high doses of HCAs developed tumors in various organs—breast, liver, colon, lung, skin, and prostate. Similar findings were observed for rodents fed with PAH-containing diet where they developed leukemia and tumors of the lungs and gastrointestinal tract.
Unfortunately, studies of these chemicals on humans are particularly difficult because of the difficulty encountered in determining the exact amount of HCAs and PAHs that a person consumes, based on questionnaires regarding their daily food intake. Other variable factors that make human studies hard include the varying levels of these compounds depending on the type of meat, length of cooking, and cooking temperature. Finally, the metabolism of these compounds may vary from person to person. Some people could have a higher risk for cancer.
For these reasons, human studies cannot generate a direct link between HCAs and PAHs to cancer development. However, there is a review article that concluded that most studies found that those who eat large quantities of grilled and well-done meats have an increased risk for cancer. Another study in 2017 also found that women with breast cancer who consumed greater amounts of grilled, smoked, or barbecued meats had lower survival rates.
For acrylamide, animal studies have also shown the link of this substance to cancer. According to the Food and Drug Administration (FDA), high levels of this substance may cause various types of cancer. Like HCAs and PAHs, human studies on acrylamide are inconclusive due to the same reasons—difficulty in estimating the daily intake level in a person’s diet as well as varying cooking temperatures, food storage, and length of cooking.
While categorized by the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives as a concern, further study of the potential cancer risk of acrylamide is recommended. Meanwhile, the U.S. National Toxicology Program and the International Agency for Research on Cancer consider this chemical a probable human carcinogen or reasonably anticipated to be a human carcinogen.
With the insufficiency of human studies, the FDA has not established yet the acceptable levels of acrylamide in a diet and does not advise against eating acrylamide-containing foods. It rather recommends eating a balanced, healthy diet—variety of vegetables, fruits, grains, low-fat or fat-free dairy products, and proteins.
How to reduce cancer risk in grilled or charred foods
Although there is no official recommendation for totally avoiding grilled or charred foods, there are several ways to reduce the carcinogens in these foods.
- Marinate
Marinating meats for about 20 minutes before grilling may reduce HCA formation. A review article in Natural Medicine Journal found that adding marinate ingredients like garlic, rosemary, fruit pulp, and other seasonings may lower HCA formation by as much as 70%.
- Trim the fat
Due to the fat pyrolysis that happens during grilling, it is therefore advised to trim fat from meat before grilling. Doing this helps reduce PAH levels in grilled meats.
- Cook at lower temperatures
It is already established that high cooking temperatures induce the development of carcinogens. Low-temperature cooking methods like baking, broiling, and sous-vide are better options.
- Use a gas grill if possible
If used correctly, gas grills are a better option than charcoal grills because of lower carcinogen emission. They produce lesser carcinogens because it has greater flexibility when it comes to controlling the temperature.
- Consider microwaving before grilling
Microwaving the meat before high heat exposure can significantly decrease carcinogen formation because of the reduced time required for grilling.
- Manage the flames
Before putting the meat on the grill, make sure that the flames have died down.
- Use the right charcoal
The type of charcoal does not have a significant difference in red meat, studies found that grilling salmon in coconut shell charcoal develops significantly lower PAHs than wood charcoal.
For other cancer risk factors, check Cancer and Risk Factors.
