Acrylamide May Suppress Autophagy

A study published in 2021 found that acrylamide can inhibit autophagy, at least in cells in a petri dish. Acrylamide is an industrial chemical used in the plastics industry, found in cigarette smoke, and, we learned in 2002, in a bunch of foods, most notably French fries and potato chips. Because it’s considered a “probable human carcinogen,” by law, a glass of water has to have less than 0.12 millionths of a gram. McDonald’s French fries were found to exceed that concentration by more than 500-fold. However, acrylamide was only considered carcinogenic because it causes cancer in lab rats. So does saccharin, but the reason we don’t see warning labels on Sweet & Low anymore is because it turned out that male rats have a unique biochemical pathway, not shared by human beings, that turns saccharin into a carcinogen. Forget people—the risk can’t even be extrapolated to female rats!

Early population-based studies suggested higher risk of endometrial, ovarian, and kidney cancer among those exposed to the most dietary acrylamide. This led to modelling studies calculating that one or two French fry-eating children out of every hundred thousand might go on to develop cancer they otherwise might not have had had they skipped the fries. Thankfully, updated meta-analyses of population studies found no significant correlation between acrylamide intake and these cancers, calming concerns until a 2018 study found that high acrylamide exposure was associated with doubling the chances of premature death. That would be consistent with an anti-autophagy effect, but how do we know acrylamide exposure isn’t just a proxy for a bad diet? A diminished lifespan among frequent feeders of fast food and salty snacks isn’t exactly a revelation. You don’t know if it’s cause and effect, until you put it to the test.

Researchers had study subjects eat a bag of potato chips every day for a month after switching from weeks of eating the same amount of potatoes in boiled form, mixed with the same fat and salt as the potato chips. In this way they hoped to isolate out the effects of the acrylamide. C-reactive protein levels shot up 50 percent, suggesting “chronic ingestion of acrylamide-containing products induces a proinflammatory state. But, acrylamide isn’t the only potentially harmful byproduct of deep frying. Deep-frying causes the formation of all manner of “undesired food-borne toxicants;” so, we can’t be sure it was the acrylamide.

Noxious chemicals, such as acrolein and other aldehydes, are formed when fat is fried; polycyclic aromatic hydrocarbons, such as benzopyrene and heterocyclic amines, are produced when muscle is fried. Indeed, fried chicken and fish were more closely tied to increased mortality than other fried foods, suggesting non-acrylamide components of deep frying may be more salient. Even just a single serving of fried chicken a week was associated with a 13 percent increased risk of premature death in a study of more than 100,000 postmenopausal women.

Whether or not the acrylamide in French fries and potato chips is actively impairing autophagy in consumers, there are certainly more salubrious sides and snacks for health and longevity. As one of the earliest geriatric medicine textbooks presciently concluded back in 1849, “frying, is an abomination.” (Though air-frying produces about 90 percent less acrylamide if you just must have your French fry fix.)