Cindy D. Davis

We all worry about making sure our meat is adequately cooked in order to avoid bacterial infection but did you know that cooking meat -beef, poultry and fish- at high temperatures for long periods of time can also be dangerous to your health? A growing number of epidemiologic studies suggest a relationship between methods of cooking meat and various cancers.

Different methods of cooking expose foods to different temperatures. Steaming, boiling and stewing expose food to heat not exceeding 100^oC; baking , microwaving and roasting expose food to temperatures up to 200 ^oC; and broiling and barbecuing use temperatures up to 400^oC. Frying with a pan or wok normally uses high surface temperatures.

It has been shown that well-cooked meat has as many as 20 compounds known as heterocyclic amines, or HAs for short. The amounts of the different HAs in food vary with the type of food and the method of cooking. In general, broiling and frying produce high levels of HAs and steaming, boiling and stewing of meats produce little or no formation of HAs . Specifically, it is the burning of meat juices that generates these compounds. Most fast-food hamburgers do not have high amounts of HAs.

In long-term feeding studies, these compounds have produced cancers in various organs of laboratory animals, suggesting that they are human carcinogens. Furthermore, HAs have also been shown to be toxic to the heart in animals and therefore may play a role in the development of chronic heart disease in humans.

To put the risks of under- versus overcooking meat into perspective, the Centers for Disease Control and Prevention reported 340 cases of E. coli infection in 1997. This corresponds to an incidence rate of 2.1 per 100,000. In contrast, scientists have estimated that the average cancer risk because of heterocyclic amine exposure ranges from 1 per 10,000 for the average person to greater than 1 in 50 for those ingesting large amounts of well-done muscle meats, especially flame-grilled chicken.

In light of the possible role of HAs in the development of human cancer and/or chronic heart disease, it appears prudent to minimize exposure to these compounds. Simple measures for doing so include avoiding overcooking of meats and preparing meats by stewing or microwaving rather than by broiling or pan-frying; if making gravy from meat droppings do not allow them to become dry prior to preparing the gravy; eat beef medium or medium-well rather than well done; when barbecuing, wrap meat or fish in aluminum foil to prevent contact with an open flame; and remove the blackened parts of charred food prior to eating. Furthermore, briefly microwaving meat and pouring off the juices before frying, broiling or barbecuing greatly reduces heterocyclic amine formation because juices contain high amounts of precursors.

So, enjoy your meat but be careful how you cook it!

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