Our favorite terrible-yet-delicious food—French fries—now has another sad strike against it. A new study finds that fries, along with other types of fried potatoes, increase our risk of mortality over the years. Other types of potato preparations didn’t seem to have the same risks involved, which suggest there’s something intrinsic about the fried-ness of French fries that makes them not just unhealthy, but actually (well, potentially) deadly. The study was published this week in the American Journal of Clinical Nutrition .
In the study, the team of researchers from England, Italy, Spain and the U.S. looked at data from 4,400 people between 45 and 79 years of age, and followed their dietary patterns and health over eight years. By the end of the study period, 236 of the participants had died.
Eating more potatoes in general didn’t do anything bad in and of itself—but when the type of preparation of the potatoes was taken into account, the team found that fried potatoes of any kind, including French fries and hash browns, twice a week or more did increase the mortality risk. And it increased it by twofold.
The study was just a correlation, of course, which means that we can’t assume that the French fries actually caused the death per se. The researchers tried to control for a number of potentially confounding variables, like weight and activity level, which helps reduce the amount of noise in the study, but there could certainly be other factors at play, which explain the connection. (It would be unethical to do a randomized control trial on it, since you can’t ethically ask participants to increase their French fry consumption and then measure their death risk.)
But assuming that the relationship is solid, what is it about fried potatoes that might contribute to mortality risk? It could certainly be the amount of trans fats in French fries, which are known to pose a serious health hazard, or the amount of salt which, although there’s more debate about it these days, seems to be linked to heart risk. And it could be a domino effect: The authors suggest, “a higher consumption of fried potatoes could increase the risk of other chronic diseases, such as obesity, hypertension, and diabetes, which are also powerful risk factors for [cardiovascular disease].”
And then there’s the chemicals in fried potatoes: Acrylamide, which is especially present in overcooked fries and potato chips (and toast) has been linked to cancer risk in animal studies, and is likely a risk to humans, too. In fact, a few years ago, the FDA warned against taking in too much acrylamide, and more recently, the British government launched a campaign to encourage people to "go for the gold," and not overcook their potatoes or over-toast their bread.
Potatoes in general pose a bit of a conundrum, since they are both healthy and unhealthy: Their starchiness makes them a high-glycemic food, and therefore a risk to cardiovascular and metabolic health. But they are high in fiber and water, and contain a lot of nutrients, which are all benefits. While researchers are still sussing out just what about French fries and other types of fried potatoes makes them so risky, it may be wise to limit them, and see them as an unhealthy once-in-a-while indulgence, rather than a staple.