How Grilling of meat products leads to formation of carcinogens???

Outdoor grilling is a popular cooking method, primarily because of the wonderful taste it imparts on meats. It can also be a healthy alternative to other cooking methods, because some of the meat's saturated fat content is reduced by the grilling process. However, grilling also presents a health risk.

After scientists discovered the carcinogenic components in cigarette smoke, they questioned whether carcinogens could also be found in foods that were smoked or burned, such as meats. In 1977, cancer-causing compounds, now known to be heterocyclic amine, were discovered in food as a result of normal household cooking processes. A total of 20 compounds fall into the category of heterocyclic amines, often abbreviated HCAs.

Two separate types of carcinogenic compounds are produced by high-temperature grilling:

• Heterocyclic Amines (HCAs)

The compounds found in food are formed when creatine (a non-protein amino acid found in muscle tissue), other amino acids, and monosaccharides are heated together at high temperatures (125-300^o C or 275-572^o F) or cooked for long periods of time. HCAs form at the lower end of this range when the cooking time is long; at the higher end of the range, HCAs are formed within minutes. The most potent of the HCAs, MeIQ, is almost 24 times more carcinogenic than aflatoxin, a carcinogen produced by mold.

Most of the 20 HCAs are more toxic than benzopyrene, a carcinogen found in cigarette smoke and coal tar. MeIQ, IQ, and 8-MeIQx have been reported as the most potent mutagens using the Ames test. These HCAs are 100 times more potent carcinogens than PhIP, the compound most commonly found as a result of normal cooking procedures.

HCAs form when a meat is directly exposed to a flame or very high-temperature surface. The creatine-rich meat juices react with the heat to form various HCAs, including amino-imidazo-quinolines, amino-imidazo-quinoxalines, amino-imidazo-pyridines, and aminocarbolines. HCAs have been shown to cause DNA mutation, and may be a factor in the development of certain cancers.

•       Polycyclic Aromatic Hydrocarbons (PAHs)

PAHs form in smoke that's produced when fat from the meat ignites or drips on the hot coals of the grill. Various PAHs present in the resulting smoke, including benzo[a]pyrene and dibenzo[a,h]anthracene, adhere to the outside surface of the grilled meat. PAH exposure is also believed to be linked to certain cancers.