When the muscles of mammals, fish, or birds are cooked at high temperatures carcinogenic chemicals called heterocyclic amines are created that may increase the risk of breast, colon, lung, pancreatic, and prostate cancer (see my last post Estrogens in Cooked Meat). Risky cooking methods don't just include barbequing, frying, and grilling. Even just baking chicken at around 350o F for 15 minutes leads to significant production of these cancer-causing compounds.
In my video Estrogenic Cooked Meat Carcinogens I showed that these cooked meat carcinogens may stimulate breast cancer cell growth nearly as much as pure estrogen. In PhIP: The Three Strikes Breast Carcinogen I showed that these chemicals may promote breast cancer invasiveness even more than estrogen.
How do you decrease your exposure to these chemicals? As you can see in my 3-min. video Reducing Cancer Risk in Meateaters, fried bacon and fish are the worst, though skinless chicken breast might lead to the greatest exposure given its popularity. Those eating out may find my video Fast Food Tested for Carcinogens useful, where chicken items from seven restaurant chains were tested to see which was worse--the answer may surprise you. And if there are carcinogens in roasted chicken, what about roasted coffee? See Carcinogens in Roasted Coffee? and Coffee and Cancer.
Women who consume meat very well done, appear to be at nearly 5 times higher risk for breast cancer compared to women who consumed their meats rare or medium done. This, however, raises the so-called "paradox" of preparing meat noted by the Harvard Health Letter. Well-cooked and you risk cancer; undercooked and you risk E. coli food poisoning (a point I also make in Carcinogens in Roasted Chicken?).
Eating boiled meat--not broiled, but boiled in water--is probably the safest. Studies show if you eat meat that never goes above 212 degrees Fahrenheit, both your urine and feces damage DNA significantly less than if you eat meat dry cooked at higher temperatures. A similar study where they compared the excretion of carcinogens formed in processed meats can be found in Prevention Is Better Than Cured Meat.
PhIP is also found in cigarette smoke, diesel fumes, and incinerator ash, but because the highest levels in food are found in common meats, toxicologists lament "Exposure to PhIP is difficult to avoid because of its presence in many commonly consumed cooked meats, particularly chicken, beef and fish." But if you're able to somehow dodge those meats (and don't suck on a cigarette, tailpipe, or incinerator smokestack) maybe it's not so difficult to avoid after all.
The levels of heterocyclic amines flowing through one's body may drop to zero after refraining from eating meat for just 24 hours. If you practice Meatless Mondays, by Tuesday, morning urine levels of PhIP and MeIQx--one the most potent mutagens ever tested--become undetectable. There are, however, ways even vegetarians may be exposed: cigarette smoke, eggs, cheese, and the popular sports supplement creatine. See my 4-min video Heterocyclic Amines in Eggs, Cheese, and Creatine? for details.
Caution may also be necessary with athletic protein supplementation. See Heavy Metals in Protein Powder Supplements. In general, Some Dietary Supplements May Be More Than a Waste of Money.
Heterocyclic amines are not the only class of meat carcinogens also found in cigarette smoke. See my video When Nitrites Go Bad. While the body can detox itself of both nitrosamines and these cooked meat chemicals within hours or days, some pollutants found in meat can persist in the body. See Industrial Pollutants in Vegans, Flame Retardant Chemical Contamination, and How Fast Can Children Detoxify from PCBs?
-Michael Greger, M.D.
Image credit: rhodes/ Flickr