Researchers have known for years that meat-eaters have higher cancer rates, compared with people who avoid meat. But now we also know that grilled meats pose a unique threat. Cancer-causing chemicals called heterocyclic amines (HCAs) have been found in chicken and other meats, and the very highest concentrations occur when these products are grilled.

Grilling meat, especially chicken, produces carcinogenic HCAs, which are formed from the creatinine, amino acids, and sugar found in muscle tissue. More HCAs are produced by long cooking times and hot temperatures, which make grilling, pan frying, and oven broiling particularly dangerous cooking methods.

The federal government added HCAs to its list of carcinogens in January 2005. But most Americans remain unaware that these compounds lurk in cooked meat. As known mutagens, HCAs can bind directly to DNA and cause mutations, the first step in the development of cancer.

Grilling is also problematic because when fat from meat drips onto an open flame, carcinogens called polycyclic aromatic hydrocarbons (PAHs) form and are deposited back onto the meat through smoke.

Scientists have discovered more than 16 different HCAs. One type commonly found in grilled meats is PhIP, which has been on California’s list of cancer-causing chemicals for more than a decade. Scientists have not determined a safe consumption level of PhIP, meaning that any amount is believed to potentially increase cancer risk.

Recent studies have shown that the consumption of well-done meat, which contains PhIP and other HCAs, is associated with an increased risk for colon, rectal, esophageal, lung, larynx, pancreatic, prostate, stomach, and breast cancer, and non-Hodgkin’s lymphoma.

In a recent review of 30 epidemiologic studies on the link between eating well-done meat and cancer at various sites, 80 percent of the studies showed a positive correlation. HCAs have also been specifically linked to colorectal cancer: One review found that high cooking temperature increased colon cancer risk almost twofold and increased risk for rectal cancer by 60 percent.

Meat cooked at high temperatures may also increase the risk of pancreatic cancer, according to a study presented at the American Association for Cancer Research annual meeting. In this nine-year study, researchers analyzed information on meat consumption and preferred cooking methods for 62,581 participants. Participants who cooked meat at high temperatures and consumed more well-done meat had about a 60 percent higher risk of pancreatic cancer, compared with other people.

Many people switch to chicken and fish, believing these to be healthier alternatives to beef. But that is not the case. Grilled chicken produces more than 10 times the amount of the carcinogenic HCAs found in grilled beef. Furthermore, nearly all the HCAs detected are in the form of PhIP, which has specifically been implicated in breast cancer risk. Fish also contains significant amounts of creatine, one of the other main ingredients for the formation of the carcinogens.

HCAs are not the only cancer risk that comes from eating meat. Countries with a higher fat intake, especially fat from animal products, have a higher incidence of breast cancer. One hypothesized reason is that low-fiber, high-fat foods increase the amount of estrogen in the bloodstream, which encourages breast cancer cell growth. A similar phenomenon can occur when men eat high-fat fare, leading to a higher risk of prostate cancer.

The consumption of meat and other fatty foods is strongly linked to colon cancer. Recent studies have shown that red meat—even red meat cooked at a low temperature—can increase colon cancer risk by as much as 300 percent.

These facts seem to pose a dilemma for meat-eating consumers. Cook chicken or beef too little, and you could easily end up with a bacterial infection. Turn up the heat enough to kill the bacteria, and you may create cancer-causing compounds.

There is a healthy—and delicious—alternative. Instead of meat products, try grilling up a homemade veggie burger or vegetable-and-tofu kebobs.

Since creatine, one of the ingredients for the formation of HCAs, is mostly found in muscle tissue, it is not surprising that grilled veggie burgers and other vegetarian foods contain either no HCAs or negligible levels.

Choosing plant-based foods instead of meat also lowers cancer risk in other ways. Not only are vegetables low in fat and high in fiber, they also contain many cancer-fighting substances. Carotenoids, the pigment that gives fruits and vegetables their dark colors, have been shown to help prevent cancer. Beta-carotene, present in dark green and yellow vegetables, helps protect against lung cancer and may help prevent cancers of the bladder, mouth, larynx, esophagus, breast, and other sites. Many studies have found that diets rich in fruits and vegetables and low in animal fat cut cancer risks.

Want to grill up something healthy? Visit www.CancerProject.org for delicious vegetarian recipes, information on nutrition and cooking classes, fact sheets on nutrition and cancer, DVDs, videos, books, and a free copy of The Cancer Project’s booklet Healthy Eating for Life: Food Choices for Cancer Prevention and Survival.

By Jennifer K. Reilly, R.D.
The Cancer Project