Carcinogens to Go?

Chicken is a staple of most bodybuilding diets. Eat it baked or grilled minus the skin, which contains the majority of chicken’s fat, and it’s a rich source of lowfat, no-carb protein. Since many bodybuilders eschew red meat because of its alleged high fat content, chicken and fish become the primary precontest protein sources. In fact, leaner cuts of beef, such as sirloin and round, don’t contain a lot of fat. Grass-fed beef offers an even better fat profile, containing less saturated fat than feed-lot beef and more conjugated linoleic acid, a.k.a. CLA, a type of fat that some studies associate with greater fat loss. Nonetheless, old dogma never seems to die, and chicken remains popular among bodybuilders. There are, however, potential problems with eating large amounts of chicken.

Among them is bacterial contamination. A few years ago I mentioned a survey of chicken purchased at several commercial outlets. Nearly all the samples were found to contain high levels of bacteria called campylobacter, which causes food poisoning. The study was alarming. In truth, however, cooking the meat likely destroyed most of the bacteria, explaining why most people who eat cooked chicken don’t show any signs of food poisoning.

Speaking of cooking, how chicken is cooked can relate to another possible problem. Many bodybuilders eat chicken at local restaurants after their workouts. According to a new survey, that chicken could prove hazardous to health. The study tested samples of chicken entrees at several popular chain restaurants: Applebee’s, Burger King, Chick-fil-A, Chili’s, McDonald’s, Outback Steakhouse and TGI Friday’s. The entrees tested included grilled chicken. The problem here has to do with compounds called heterocyclic amines. 

HCAs are formed when meat is cooked at high temperatures, particularly by pan frying, grilling or barbecuing. They were first isolated in the 1970s in various highly cooked meats; thus far, 17 HCAs have been found. Studies show that they cause cellular mutations in isolated-cell studies and are carcinogenic in animal studies. Other studies have linked the intake of HCAs to prostate, colon, stomach and kidney cancers. While not all studies have found a direct carcinogenic link with eating well-done meat, the International Agency for Research on Cancer has classified HCAs as possible or probable human carcinogens. The California Office of Environmental Health Hazard Assessment includes four HCAs on its list of chemicals known to be carcinogens or reproductive toxicants.

Grilled chicken contains a high count of an HCA called PhIP, which is considered the most potent HCA in relation to DNA damage that leads to cellular mutations and cancer. In the new study 100 samples of chicken were collected from the chain outlets mentioned earlier, and they all contained PhIP. The amount varied depending on the cooking method and temperature used during the cooking process. PhIP is associated with the first two stages of cancer: initiation and encouragement of tumor growth. 

Does that mean we should all avoid eating grilled chicken or well-done meats? What about other protein sources—do they also contain HCAs? They’re found only in meats because they’re formed when amino acids in meat react to high heat and to meat’s creatine and creatinine content. Since other protein sources, such as dairy and eggs, don’t contain significant amounts of creatine, they don’t produce HCA.

There are several ways to reduce the dangers of HCA in chicken and beef. The obvious one is not to overcook the meat; the higher the temperature, the more HCA is produced. Microwaving meat for two minutes before cooking reduces HCA by 90 percent. Marinating meat, especially with fruit, reduces most of the HCA production in cooked meats. You don’t want to undercook meat, especially chicken, as that opens up the possibility of bacterial food poisoning.

Various studies show that the production of HCA is part of an out-of-control oxidation process. It naturally follows that taking in antioxidants would short-circuit that effect, as studies confirm. Such dietary antioxidants as tea, garlic, red wine, fruits and vegetables all offer protection against the carcinogenic effect of putting HCAs into your body. Blueberries are particularly efficient in that regard. Some studies show that adding cherries to cooked beef (doesn’t sound very appetizing to me—or should I say berry appetizing?) totally eliminates HCA formation even in seared beef. Casein binds to HCA and leads to its rapid elimination from the body. The same holds true for dietary fiber. Quercitin, found in onions and other foods, is a flavonoid that also neutralizes HCA. Even the hops found in beer are a natural enemy of HCA synthesis.

Another factor to consider is that HCAs convert into carcinogens in the liver during phase-one metabolism. Phase-two liver metabolism detoxes various carcinogens, including HCAs. The most potent food stimulators of phase-two liver metabolism are cruciferous vegetables, such as broccoli, brussels sprouts, kale and cabbage.

Statistics show that your chance of acquiring cancer from a lifetime exposure to HCAs is 1 in 10,000—better odds than getting all six numbers in a state lottery, but still in your favor in relation to getting cancer. So go ahead and have that grilled chicken entree, but play it safe by also ordering some cruciferous veggies or perhaps a postworkout protein drink containing casein. Or you can add a clove of garlic, in which case you not only prevent cancer but also ward off any vampires that may be lurking in the area. IM

Sullivan, K.M., et al. (2008). Detection of PhlP in grilled chicken entrees at popular chain restaurants throughout California. Nutr Cancer. 60:592-602.