INDEPENDENCE, Mo. – Charbroiling, grilling over open flame, broiling and pan frying meats can produce tasty meals. Unfortunately, these methods, especially if the temperature is above 300 degrees Fahrenheit, also result in the formation of certain undesirable chemicals.

These chemicals are known as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), says Lydia Kaume, a nutrition and health education specialist for University of Missouri Extension.

The HCAs form as a reaction of meat proteins, sugars and muscle creatinine to the high heat. “Longer cooking times and heat influence the number of HCAs formed,” Kaume says. “For example, well-done, grilled or barbecued chicken and steak all have high concentrations of HCAs.”

On the other hand, PAHs are formed in open-fire grilling as fat and juice drip from meats and other charred foods, resulting in flames. These flames contain PAHs that adhere to the surface of the meat, she says.

“In general, cooking methods that expose meat to smoke or charring contribute to PAH formation,” Kaume says. “PAHs are also found in smoked meats, cigarette smoke and car exhaust fumes.”

These chemicals are of concern because HCAs and PAHs in food can damage our DNA. In laboratory studies involving animals, researchers found that exposure to HCAs and PAHs can cause tumors of breast, colon, liver, skin, lung, prostate and other organs.

Similar studies in humans are difficult to conduct because it is difficult to control for individual differences, exact levels of these chemicals consumed and other factors. Instead, scientists have conducted numerous epidemiological studies using questionnaires to examine participants’ meat consumption and cooking methods to estimate HCA and PAH exposures. These studies have found that high consumption of well-done, fried or barbecued meats is associated with increased risks of colorectal, pancreatic and prostate cancer.

“An interesting fact to note is that individuals have different bioactivation levels, which means that cancer risks associated with exposure to HCAs and PAHs may vary from one person to another,” Kaume says.

While researchers continue to study this subject, there are ways to reduce your exposure:

· Avoid prolonged cooking times at high temperatures as well as direct exposure of meat to an open flame.

· Use a microwave oven to cook meat prior to exposure to high temperatures to lower the time for HCA formation.

· Regularly turn meat over on a high heat source.

· Get rid of charred portions of meat or other foods.

· Avoid using gravy made from meat drippings.

For more information, see the National Cancer Institute fact sheet “Chemicals in Meat Cooked at High Temperatures and Cancer Risk” at cancer.gov/cancertopics/factsheet/Risk/cooked-meats.