DEAR DR. ROACH: It seems that my once-weekly steak should not be barbecued, due to carcinogenic factors. A disappointment. How important is this effect? — S.
ANSWER: Grilling meat of any kind leads to the formation of two separate families of cancer-causing chemicals (carcinogens): the heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons. The old adage remains true that the dose makes the poison.
Eating grilled meat less often will reduce your overall exposure, and there are steps you can take during cooking to reduce the generation of these toxic chemicals. These include meticulous cleaning of the grill to get rid of the char already there; marinating your protein, which reduces formation of these toxins; using herbs (likewise); cooking at lower heat or reducing time on the grill by combining with other cooking methods; and cooking lots of grilled vegetables as well (which do not form these toxins when grilling).
I have always recommended reducing, not eliminating, your less-healthy food choices. If you like your grilled steak, make it as safely as possible and enjoy it. The harm from eating these occasionally is small.