When meat is cooked using high heat, carcinogenic compounds called heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are formed. But the carcinogens are more about the meat than the method of cooking.
The formation of HCAs is “not a problem in vegetables,” says Dee Sandquist, who is a registered dietitian and a spokesperson for the American Dietetic Association. A fact sheet put out by the National Cancer Institute explains that “HCAs form when amino acids (the building blocks of proteins) and creatine (a chemical found in muscles) react at high cooking temperatures.” Vegetables don’t contain creatine, so they don’t produce HCAs.
PAHs are formed only when you grill over an open flame and meat fat drips onto the flames, says Krista L. Haynes, staff dietitian for the Cancer Project, a nonprofit organization that researches the links between nutrition and cancer. Carcinogens then rise in the smoke and adhere to the surface of the food. Increased temperature and longer cooking times lead to higher levels of both PAHs and HCAs.
Only a minimal number of PAHs are formed when vegetable-based fat is burned, says Haynes, and “the amount [of oil] used at home wouldn’t produce significant levels.”