Do chemicals in cooked meat cause cancer?
There have been a ton of news stories and links going around about the chemicals in cooked meat that can cause cancer. They all say don't eat meat, you won't get cancer...which we all know that there are many different reasons for cancer to occur, but one of them is a genetic marker, meaning that some people are predisposed to getting cancer (i.e. if a close family member mother, father, brother, sister has cancer). The science behind Heterocyclic Amines (HCAs) and Polycyclic Aromatic Hydrocarbons (PAHs) is real, but the question of whether they cause cancer is another question.
What are HCAs and PAHs?
Simply, HCAs and PAHs are the chemicals that are formed when cooking muscle meat (from fish, beef, pork, and poultry) at high temperatures and/or over open flames (like grilling). As the meat cooks, we are changing the chemical composition: chicken goes from being slimy and pink, to white and firmer (something that you would actually want to eat). Throughout that cooking process, especially at high temperatures, there are more HCAs and PAHs present. The HCAs form when the amino acids (protein), sugars, and creatine (part of the musculature) react to the high temperature. The HCAs bare not frequently found in foods that are not cooked at high temperatures. The PAHs are formed when the fat from your meat drips into the grill, creates a big flame; those flames contain the PAHs that then adhere to the outside of the meat. PAHs are also found in cigarette smoke, when smoking meats, and car exhaust (if it tastes "smokey" most likely it has PAHs). Also, it is interesting to note that the more "well done" your meat is, the higher the level of HCAs because the longer it has cooked and the more chemical change has occurred to the meat....so you might want to start appreciating a nice rare steak ;)
Do they cause cancer?
HCAs and PAHs have been shown, in lab studies, to cause changes in DNA which can possibly cause cancer. The studies were done on lab rats that were fed diets high in HCAs: the rats then grew tumors in their breast tissues, liver, pancreas, colon, skin, lung, prostate, and other tissues. With PAHs, the rats had tumors of the stomach (entire Gastrointestinal tract), leukemias (blood cancer), and lungs. BUT these rats were fed thousands of times the amount of HCAs and PAHs that any human being would be consuming, and truly any chemical would cause cancers at that level. Population studies of different people in their natural habitat have not shown any increase in cancer with HCAs and PAHs; the caveat is that if someone lives in an area with high levels of exhausts or fumes, their exposure to PAHs are higher, so they are at risk of cancer from that, but not specifically due to ingesting cooked meats. The environmental exposure to PAHs are more of a risk than cooked food. As well, peoples genetic risk is also a factor here: if you had a genetic predisposition to cancer, your body may be more susceptible to DNA changes causing cancer from HCAs versus someone who has a very low risk and no cancer in their family. Although, those with a diet high in well done, barbecued, and fried meats have higher risks of colon, pancreatic, and prostate cancer....but there are other risk factors there as well (which can include a sedentary lifestyle, lack of vegetables, preventative care, etc.)
How do I decrease my exposure?
I wouldn't tell you to stop eating meat based on this one outrageous study, but if you are worried about it, there are ways to still enjoy a tasty piece of meat, but decrease your exposure to HCAs and PAHs. YAY!
-Cook meat lightly in a microwave, then pan sear or cook on a grill to finish the cooking process (decreasing the amount of time over high heat significantly decreases the amount of HCAs present) OR partially bake in the oven then grill.
-Continuously moving meat over high flame can decrease HCA creation- instead of leaving that burger sitting there to cook a few minutes on each side, think rotisserie chicken, and keep it constantly moving to cook, which will decrease PAHS from adhering to it.
-Remove charred bits of meat, and don't make gravy or other sauces from meat dripping when grilling, it will significantly reduce the amount of HCAs and PAHs you ingest.
-Eat meat that is more rare, as opposed to well done!
Looking at all the research, I would not stop eating meat based on what is out there. But if you are concerned, head towards rare meats, bake in the oven, use that microwave, and maybe don't eat grilled meat EVERY night of the week! Remember that when studies are done, based on the funding the researchers get, they want exposure, and so do the people funding the studies, so they will create "science" and then make it a media sensation to get everyone talking about it- mission accomplished on this one! Rest assured there are studies that are taking into account normal levels of ingested HCAs and PAHs and the FDA/US Govt has not made any recommendations to change your lifestyle based on this one study. So keep eating healthy, and if you are concerned, talked to your HCP about it!
Yours in Good Health