Bacon and other processed meats increase colorectal cancer risk

Hot dog at baseball games. Bacon on Sunday mornings. German sausage on the barbecue. American culture is full of joyous occasions that often include the consumption of processed meats. But, according to experts, the most recommendable thing is that this indulgence is nothing more than an occasional pleasure.

“There is very compelling evidence that regular consumption of processed meats is harmful to health, including colorectal cancer, type 2 diabetes and cardiovascular disease,” said Frank Hu, professor of nutrition and epidemiology and director of the department of nutrition at the Harvard T.H. Chan School. of Public Health. And, he said, most health experts agree that “processed meats are more harmful than unprocessed meats.”

Among the processed meats are ham, sausage, bacon, bologna, smoked turkey, salami, sausages, jerky, pepperoni and even sauces made with these products. When meat is processed, it is smoked, fermented, cured or salted to intensify its flavor and extend its shelf life.

The WHO (World Health Organization) declared in 2015 that processed meats are carcinogenic to humans, citing “sufficient evidence” that they cause colorectal cancer.

The World Cancer Research Fund International recommends minimal or zero consumption of processed meats and that red meat be limited to about three servings per week (a total of 350 to 500 grams).

It’s important to limit your consumption of red meat — most commonly, in the US, beef or pork — even when it’s unprocessed, because it’s linked not only to cancer but also to cardiovascular disease, stroke, and overall risk of death. (In its 2015 statement on processed meat, the WHO classified red meat as “probably carcinogenic”.)

Due to the way research is conducted today, experts cannot recommend one type of processed meat over others. Hu explained, “Most studies focus on highly processed meats — sausages, sausages, bacon.”

So, he said, because in most studies all types of processed meats are treated together, “it’s hard to say conclusively which processed meats are better or worse than others.” In addition, people who regularly consume one type of processed meat tend to eat others as well, so it is difficult to differentiate the effects of one type or another.

“Theoretically, we can argue that processed poultry and fish are not as harmful as processed red meat,” Hu said, citing the lower saturated fat content of poultry and fish and the abundance of omega-3 fatty acids in certain types of fish. . “But we don’t have the evidence to support this,” so until further research is done, it’s best to treat processed poultry and fish with the same caution.

That’s because it appears the biggest problem is with the processing itself, not the origin of the processed meat, said Marji McCullough, senior scientific director of epidemiological research at the American Cancer Society. The act of curing and preserving meats with nitrates and nitrites, which can create carcinogenic chemical compounds in food, may contribute to cancer risk, she explained.

Another possible variable is that cooking meats at high temperatures can form additional carcinogens. This includes preparing the meat in direct contact with a flame or hot surface, such as when grilling, frying, or barbecuing.

In addition to cancer risks, all processed meats tend to be high in sodium, which is an important factor, Hu said. Excessive sodium can increase the risk of hypertension and cardiovascular disease.

Processed meats have also been linked to a higher risk of developing type 2 diabetes and dementia. For example, a large 2021 study done in the UK found that for every additional 25 grams of processed meat in a person’s daily diet, their risk of dementia increases by 44% and their risk of Alzheimer’s disease by 52%.

Vijaya Surampudi, an adjunct professor of medicine at UCLA’s Center for Human Nutrition, said the concern about processed meat is that it can increase inflammation in the body, in part by altering the gut microbiome.

“The gut bacteria react with our immune system, and that ultimately leads to chronic inflammation,” she said, which can affect blood pressure, blood sugar and cholesterol, raising the risk of chronic disease and even death.

“A plant-based diet reduces these risks,” Surampudi said. “That doesn’t mean you have to be 100% vegan or vegetarian,” just that most of your food should be derived from plant sources.

This type of food is also more beneficial to the environment.

So does that mean it’s better to consume processed plant-based meat alternatives?

“Processed meat alternatives are potentially better than processed meats, but not all processed alternative products are created equal,” Hu said. It depends on what they are made of: if they are analogues of entirely plant origin or if they are products made with a mixture of meat and vegetables. In any case, he pointed out, “a more ideal diet should be based on minimally processed plant foods.”

What about products whose labels say “no added nitrates or nitrites”? Nitrate-free meats may use ingredients like celery juice, a natural nitrate, but it’s not clear whether they’re better for your health than products made with nitrates or synthetic nitrites.

As for products labeled “organic”, “antibiotic-free”, “vegetarian-fed” or “cruelty-free”, Surampudi commented, “I think if people can choose lean cuts of meat, organic meats or animal-fed with a vegetarian diet, that’s better. That’s because what the animal you’re consuming is concentrated in your body, and then we consume it.” It is important to take this factor into account with all foods of animal origin, processed or not.

Ultimately, the processed meats that do the most harm are the ones people routinely consume, rather than reserving them for the occasional treat. In other words, enjoy your hot dog or sausage every now and then – for example, at a baseball game or a family barbecue. Just don’t make it a habit.

Translation by Clara Allain