Heterocyclic Amines in Cooked Meats
Taken from the National Cancer Institute
Research has shown that cooking certain meats at high temperatures
creates chemicals that are not present in uncooked meats. A few of these
chemicals may increase cancer risk. For example, heterocyclic amines
(HCAs) are the carcinogenic chemicals formed from the cooking of muscle
meats such as beef, pork, fowl, and fish. HCAs form when amino acids
(the building blocks of proteins) and creatine (a chemical found in
muscles) react at high cooking temperatures. Researchers have identified
17 different HCAs resulting from the cooking of muscle
meats that may pose human cancer risk.
Research conducted by the National Cancer Institute (NCI) as well as
by Japanese and European scientists indicates that heterocyclic amines
are created within muscle meats during most types of high temperature
cooking.
Recent studies have further evaluated the relationship associated
with methods of cooking meat and the development of specific types of
cancer. One study conducted by researchers from NCI's Division of Cancer
Epidemiology and Genetics found a link between individuals with stomach
cancer and the consumption of cooked meats. The researchers assessed the
diets and cooking habits of 176 people diagnosed with stomach cancer and
503 people without cancer. The researchers found that those who ate
their beef medium-well or well-done had more than three times the risk
of stomach cancer than those who ate their beef rare or medium-rare.
They also found that people who ate beef four or more times a week had
more than twice the risk of stomach cancer than those consuming beef
less frequently. Additional studies have shown that an increased risk of
developing colorectal, pancreatic, and breast cancer is associated with
high intakes of well-done, fried, or barbequed meats.
Four factors influence HCA formation: type of food, cooking method,
temperature, and time. HCAs are found in cooked muscle meats; other
sources of protein (milk, eggs, tofu, and organ meats such as liver)
have very little or no HCA content naturally or when cooked. Temperature
is the most important factor in the formation of HCAs. Frying, broiling,
and barbecuing produce the largest amounts of HCAs because the meats are
cooked at very high temperatures. One study conducted by researchers
showed a threefold increase in the content of HCAs when the cooking
temperature was increased from 200° to 250°C (392° to 482°F). Oven
roasting and baking are done at lower temperatures, so lower levels of
HCAs are likely to form, however, gravy made from meat drippings does
contain substantial amounts of HCAs. Stewing, boiling, or poaching are
done at or below 100°C (212°F); cooking at this low temperature creates
negligible amounts of the chemicals. Foods cooked a long time
(“well-done” instead of “medium”) by other methods will also form
slightly more of the chemicals.
One study has evaluated the content of HCAs in fast food restaurants.
After evaluating five kinds of meat products from various fast food
restaurant chains, the study concluded that there were low levels of
HCAs found in fast food meat products due to factors such as cooking
temperature and time. The study suggested that greater exposure to HCAs
stems from home cooking and cooking in non-fast-food restaurants where
food may be cooked to order and where a larger amount of meat is
consumed.
Studies are being conducted to assess the amount of HCAs in the
average American diet, but at present the maximum daily intake of HCAs
in food has not been established. At the moment, no Federal agency
monitors the HCA content of cooked meats (how much a person could be
eating), there is no good measure of how much HCAs would have to be
eaten to increase cancer risk, and there are no guidelines concerning
consumption of foods with HCAs. Further research is needed before such
recommendations can be made.
Note From Naturalhealthway: To avoid cancer causing HCA's simple include more raw foods in the diet and avoid foods cooked at 200 degrees F or above. The healthiest way of cooking food from my research is lightly steamed or in the case of meat, to cook it in a crock pot in water until it reaches a temperature of 160 degrees. Besides preventing HCAs, this form of cooking also prevents cholesterol from oxidizing which is harmful. Non-oxidized cholesterol in not unhealthy and does not contribute to heart disease.
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