And in 2015, the World Health Organisation dubbed it a probable carcinogen, too. Steak lovers panicked, understandably—but the designation probably doesn’t mean the end of juicy fillets.
Categorising red meat as potentially cancer-causing refers most directly to colorectal cancer, but even the strongest scientific evidence in this area is still considered somewhat limited. It looks like processed red meat—think hot dogs, sausage, and bacon—may be the real culprit. Processed meats were designated Group 1 carcinogens by the WHO, a more dangerous ranking than the Group 2A given to unprocessed red meat, because many contain nitrates and nitrites, salts that are thought to be directly related to cancer. “We can’t say there’s a safe level of intake of processed meat,” says Carolina Guizar, a registered dietitian and nutritionist with New York City meal delivery nonprofit God’s Love We Deliver. “It’s pretty clear that the more processed meat you have, the greater your risk for colorectal cancer.”
You’ve long been wary of the saturated fat and cholesterol in red meat, no doubt, but the research examining the link between eating red meat and heart disease has actually been mixed. In one review of 11 different studies, four found an increase in heart disease risk when people ate more red meat while five didn’t, Guizar says. Another review found only a weak link between red meat and heart disease, but a stronger link between processed meat and heart problems.
It actually might be the salt in processed red meat that’s the big concern, says Simin Liu, MD, ScD, professor of epidemiology at Brown University’s School of Public Health who researches nutrition and heart disease, among other topics. “Sodium in particular is a risk factor for high blood pressure, which in turn elevates heart disease risk,” he says. Iron intake from red meat has also been linked to heart disease and heart attack, he adds, not to mention saturated fat probably shouldn’t be let entirely off the hook.
Because stroke shares so many risk factors with heart disease, it’s likely also linked to red meat consumption because of salt, namely those nitrites and nitrates again, Liu says. A review of studies examining stroke risk found that for every serving per day increase in red meat consumption, ischemic stroke risk increased by 13 per cent, or by 15 per cent when only processed meat was taken into consideration.
Liu’s research estimated that for every serving per day your red meat intake increases, your risk of type 2 diabetes goes up by somewhere between 9 and 18 per cent. Again, processed meat seems to be more problematic than unprocessed, and (noticing a theme yet?) nitrites and nitrates seem to be to blame, Liu says. Some of the same cancer-causing chemicals that can form while cooking red meat are also toxic to the cells in the pancreas that produce insulin, at least in studies of animals. Of course, eating red meat could cause you to pack on a few extra pounds, which could in turn increase diabetes risk, Liu adds. But it’s frequent consumption that he’s most concerned about.
“The average healthy person should not be worried about having a hamburger or a steak occasionally,” he says. The study results come from comparing people who eat red meat five or more times a week and people who eat it less than once a week. “Red meat consumed in modest portions and low frequency would not convey high risk of developing type 2 diabetes,” he says.