Grilling usually involves a significant amount of direct, radiant heat, and tends to be used for cooking meat quickly. A growing body of research suggests that cooking meats over a flame is linked to cancer.
                  
Direct heat grilling can expose food to temperatures often in excess of260 °C (500 °F). Grilled meat acquires a distinctive roast aroma and flavor from a chemical process called the Maillard reaction.

            

Generally ‘grilling’ is a form of cooking that involves dry heat applied to the surface of food, commonly from above or below.


Grilling usually involves a significant amount of direct, radiant heat, and tends to be used for cooking meat quickly. Food to be grilled is cooked on a grill,a grill pan or griddle. Heat transfer to the food when using a grill is primarily through thermal radiation. Heat is transferred when using a grill pan or griddle is by direct conduction.


Grilling meats is an American tradition, but it’s not the healthiest thing to do. A growing body of research suggests that cooking meats over a flame is linked to cancer.


Direct heat grilling can expose food to temperatures often in excess of260 °C (500 °F). Grilled meat acquires a distinctive roast aroma and flavor from a chemical process called the Maillard reaction. The Maillard reaction only occurs when foods reach temperatures in excess of 155 °C(310 °F).

            

The 3D structure of Polycyclic aromatic hydrocarbon (PAH)

            

Studies have shown that cooking beef, pork, poultry, and fish at high temperatures can lead to the formation of heterocyclic amines, benzopyrenes and polycyclic aromatic hydrocarbons, which are carcinogens.


Combusting wood, gas, or charcoal emits chemicals known as polycyclic aromatic hydrocarbons. Exposure to these so-called PAHs is known to cause skin, liver, stomach, and several other types of cancer in lab animals. Epidemiological studies link occupational exposure to PAHs to cancer in humans. When PAHs from a flame mingle with nitrogen, say from a slab of meat, they can form nitrated PAHs, or NPAHs. NPAHs are even more carcinogenic than PAHs in laboratory experiments. The reasonable conclusion is that grilling meat may be hazardous to your health.


The evidence linking cancer to cooking meat over a combustion source has been accumulating for decades.Epidemiologists first noticed a connection between the consumption of smoked foods and stomach cancer in the 1960s. Japan, Russia, and Eastern Europe, where smoking is a popular way to preserve meat and fish, became laboratories for gastric cancer research. Newer studies suggest that eating smoked meats may lead to cancer even outside the gastrointestinal tract. A 2012 study, for example, linked smoked meat consumption with breast cancer.


Again, an animal and laboratory studies suggest that HCAs may damage DNA and spur the development of tumors in cells of the colon, breast, prostate and lymph system. At temperatures of 350°F and hotter, amino acids and creatine (a natural compound that helps supply energy to muscles and nerves) react to form HCAs. PAHs form when fat drips onto hot coals, creating smoke that settles on food; these compounds have been associated with increased risk of breast cancer.

            

Combusting wood, gas, or charcoal emits chemicals known as polycyclic aromatic hydrocarbons. Exposure to these so-called PAHs is known to cause skin, liver, stomach, and several other types of cancer in lab animals.

            

But "within the big picture of cancer prevention, there are much greater risks than grilling," says Colleen Doyle, M.S., R.D., director of Nutrition and Physical Activity for the American Cancer Society. For example, "if you’re 30 pounds overweight,that puts you at much greater risk for developing a number of cancers [than does eating grilled meats]."


From a 1950s perspective, cigarette that different from eating grilled or fried meat.


"Beef, pork and poultry tend to form more HCAs than seafood because of their higher amino acid content and longer grilling times," says Doyle.


Research in the Journal of Agriculture and Food Chemistry showed that marinating red meat in beer or wine for two hours significantly reduced HCAs. Scientists believe the antioxidants in these marinades block HCAs from forming. Similarly, a Kansas State University study found that rubbing rosemary, an herb known for its high level of antioxidants, onto meats before grilling cut HCA levels by up to 100percent. Herbs including basil, mint, sage and oregano may have similar effects.


In subsequent decades, it has become clear that smoking isn’t the only problematic cooking method. Frying bacon, for example, produces significant levels of PAHs, probably due to volatilization of carbon in the bacon itself. An Iranian study published last year found that people who develop certain kinds of gastrointestinal cancers are more likely to have a diet high in fried rather than boiled foods. (The researchers linked level of browning to cancer incidence, thus reducing the likelihood that oil consumption was the culprit.) The FDA and WHO also remain concerned about the presence in food of acrylamides, a known carcinogen that forms from sugar and amino acids when cooked at high temperatures. Long-term studies are currently underway. The worrying implication is that cooking foods at high heat, even without active combustion, may be dangerous.


None of these studies is definitive.It’s possible that other variables account for the correlations between cancer and cooking over a flame or at high heat, or that the carcinogenicity of PAHs observed in animal studies overstates the risk. But the risks are worth taking seriously.

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