With summer fast approaching, plans for barbecues and cook-outs are in the works.
But, in an instance of Delicious Things That Might Kill Us (see also: hot dogs and ultra-processed foods, among others), smoked foods are carcinogenic, meaning they contain properties that put us at a higher risk for cancer. Registered dietitian Nasira Burkholder-Cooley in Orange County, California assessed the possible damage smoked foods can do.
What carcinogens are in smoked foods?
The chemicals worth knowing when it comes to carcinogens (any substance capable of causing cancer) in smoked foods are polycyclic aromatic hydrocarbons (P.A.H.s) and heterocyclic amines (H.C.A.s). These compounds form when meat — beef, pork, poultry, and fish — cooks at high temperatures (above 300 degrees Fahrenheit). Sugars and amino acids that comprise proteins in meat form H.C.A.s upon reacting with heat. P.A.H.s form when fat and juice interact with the flame and stoking smoke and then adhere to that tender beef slab. So while that smoke can make the meat taste great, it can also pose a risk. But please don’t cook your meat at a lower temperature to avoid these compounds — then you’re dealing with possible bacteria from undercooked meat.
In addition to eating smoked meats, burning coal, oil, gas, wood, garbage, and tobacco smoke exposes people to P.A.H.s, according to the Centers for Disease Control. Once in the body, P.A.H.s change into a product called metabolites which pass with waste — but not without potentially causing some damage.
But cooking meat always requires high temperatures; why don’t these P.A.H.s and H.C.A.s show up in a fresh roast beef or fried chicken? According to the National Cancer Institute (N.C.I.), cooking method, type of meat, and done-ness all affect how these compounds come into play. Grilling and barbecuing chicken and beef to a well-done state amps up H.C.A.s, and any smoke exposure will drive P.A.H.s. Charring foods, even vegetables, with smoke and flame stoke these deleterious compounds (though to a much lesser degree in vegetables).
What is the risk of eating smoked foods?
H.C.A.s and P.A.H.s are mutagenic, which means they can alter our DNA in a way that increases the risk for cancer. Once in the body, H.C.A.s and P.A.H.s are metabolized by enzymes in a process called bioactivation. H.C.A.s and P.A.H.s by themselves aren’t too dangerous, but the way they break down in the body can be. The presence of P.A.H.s triggers the body to produce specific enzymes which break down the compounds. This releases byproducts that can interact with the body's DNA.
Research links these carcinogens with different types of cancer. One study from 1991 looked at the effects of a particularly abundant type of H.C.A. called PhlP in rats. Rats fed a diet for one year that included a concentration of this H.C.A. at 400 parts per million (there was a ratio of 400 parts H.C.A. to a million parts food) were more likely to develop breast and colon carcinomas. Another study from 2004 found that another type of H.C.A. produced liver cancer in monkeys. One study from 2009 in humans concluded consuming barbecued and grilled meat, especially red and processed meats, correlated with an increased risk of prostate cancer.
As is the case with so many Delicious Things That Might Kill Us, moderation is key. Nasira Burkholder-Cooley, a registered dietitian in Orange County, California, says that while ideally, a client would give up smoked and processed meat entirely, reducing intake is a good starting point.
“Cutting that back to less than once a week on average would be a good place to start, and then if you can, weed it out of your diet completely and try to find alternatives like different cooking methods,” she tells Inverse.
Smoked meats and fish make up huge chunks of various cultural cuisines. Some studies specifically look at how smoked meats affect geographic populations, such as those in Cyprus or the Baltics. Burkholder-Cooley recognizes that giving up a diet staple isn’t always feasible, so reducing intake may be easier.
Are there safer alternatives?
The NCI has a few recommendations to keep H.C.A. and P.A.H. formation low while cooking:
- Keep meat away from open flame
- Minimize cooking time
- Microwave meat first to reduce the time it needs to cook at much higher temperatures
- Continuously flip meat, don’t let it sit on hot metal for too long
- Remove charred portions
- Skip or reduce gravy made from drippings
The good (and bad) news is that smoking meat specifically proliferates these carcinogens. Ingredients like smoked paprika don’t pose nearly the same risk, according to Burkholder-Cooley, so rubbing some on an oven-baked salmon can get the smoky flavor without all the chemical compounds. Liquid smoke, which is literally the essence of wood smoke, is another good alternative.
If your summer BBQ agenda is filling up, consider trading a few burgers for something else.
CHECK, PLEASE is an Inverse series that uses biology, chemistry, and physics to debunk the biggest food myths and assumptions.
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