What are the preparation methods to reduce exposure to carcinogens in cooked meat?
What are some ways we can decrease our exposure to the carcinogenic substances in meat that are formed during cooking? At 0:15 in my video Carcinogens in Meat, I show a whole list of hazard factors. The first factor is “meat type,” with processed meat (whether red or white) being the worst, followed by “cooking temperature.” Cooking meat below 260∞F, such as by boiling or microwaving, is safer, whereas broiling, roasting, or pan-frying is the worst. Another hazard factor is “turning over during cooking” (turning over the meat every minute lowers risk) and, rather than cooking to “dark, flavorful crust formation,” it’s recommended the meat be pale and soft, that is, cooked rare, which lowers risk as long as you meet food safety guidelines. Spices or a vinegar-containing marinade lowers carcinogen formation, and you should avoid gravy and stick to one serving, which is about “the size of a deck of playing cards or a bar of soap.” You should eat vegetables and fruits with your meat and be aware that just being around “barbecue fumes…may have become a significant but largely neglected source of health threats,” even if you don’t eat anything off of it.
As you can see at 1:07 in my video, researchers estimated the extra lifetime cancer risk associated with standing about 6 feet away and 30 feet away from a charcoal grill every day, with either 25 percent skin exposure or 100 percent skin exposure. They’re not talking about grilling in the nude; this recognizes that “light and thin cloth[ing] are expected to provide negligible resistance,” that is, little protection from these gaseous carcinogens. Indeed, skin or “dermal contact is often neglected in assessments of combustion-derived PAHs,” polycyclic aromatic hydrocarbons, but we know it’s a problem from studies on firefighters that show that even when in full protective gear and breathing through a respirator, they still end up with these compounds in their bodies, likely entering through their neck under their helmets.
“These results indicated that outdoor exposure to barbecue fumes (particularly dermal contact [through the skin]) may have become a significant but largely neglected source of health hazards to the general population and should be well-recognized.” The researchers’ estimates, however, were from barbecuing once a day, every day, year-round, though they think the toxic fumes might actually stick to people’s clothing, which they could then bring inside with them to continue exposure.
These are some of the chemicals that led the International Agency for Research on Cancer, the official scientific body that determines what is and is not carcinogenic, to declare that processed meat does cause cancer and red meat probably causes cancer. The scientists considered both the nitrites in processed meat, as well as these cooked meat carcinogens. “However, due to the practically unavoidable presence of other carcinogenic compounds, which are already present in raw or unprocessed meats…these chemicals are not the only potentially carcinogenic substances in meat and meat products. These other substances are well known environmental pollutants such as some heavy metals,” dioxins, and PCBs—so-called persistent organic pollutants “to which humans are exposed to primarily via dietary intake of diary products, meat, and fish.” (Although dioxins are created when paper pulp is bleached, I have a feeling the mean “dairy.”)
How much of a problem is this in the United States? The U.S. Department of Agriculture “examined whether levels of dioxin-like compounds…in FSIS-regulated meat and poultry products indicate possible concern for U.S. public health” and concluded that “a typical U.S. adult daily exposure…is below the EPA-established RfD,” that is, the reference dose or the maximum acceptable limit of a toxic substance. “Only children consuming…average daily servings of meat or poultry products containing the highest measured levels…may exceed the RfD.” Putting all the carcinogens together, some toxicologists suggest “limit[ing] the consumption of beef, pork and chicken so that children should consume at most five servings of these meats each month (considered together)”—so, on average, that would be one serving every six days or so, max.
- Carcinogenic substances are formed in meat during cooking, and hazard factors include the type of meat, with processed meat (both red and white meat) being the worst, followed by temperature of cooking. Boiling or microwaving meat is safer, and broiling, roasting, or pan-frying is the worst.
- Turning over meat every minute while cooking lowers risk, and cooking it until it is rare (rather than to “dark, flavorful crust formation”) is recommended.
- Carcinogenic formation can also be lowered with spices or marinade with vinegar, and it’s recommended to avoid gravy, have only one card deck-sized serving of meat, eat it with vegetables and fruits, and be aware that just being in the proximity of barbecue fumes may threaten your health.
- Researchers estimate the extra lifetime cancer risk associated with standing (while clothed) about 6 feet away and 30 feet away from a charcoal grill every day, with either 25 percent skin exposure or 100 percent skin exposure. Toxic fumes may also stick to clothing, which people could then take inside with them to continue exposure.
- The International Agency for Research on Cancer has declared that processed meat does cause cancer and red meat probably causes cancer. The scientists considered both the nitrites in processed meat, as well as these cooked meat carcinogens.
- Other potentially carcinogenic substances in meat are well known environmental pollutants, such as heavy metals, dioxins, and PCBs—so-called persistent organic pollutants we are exposed to primarily via consumption of dairy and meat, including fish.
- Children in the United States consuming average daily servings of meat with the highest measured levels of dioxin-like compounds may exceed the EPA-established maximum acceptable limits of toxic substances.
- Some toxicologists suggest restricting intake of beef, pork, and chicken by children to no more than five servings a month, which would be, on average, at most one serving every six days or so.
Flashback Friday: Is Organic Meat Less Carcinogenic? Watch the video to find out.
Michael Greger, M.D.
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