New study suggests eating hot chips may be linked to depression

French fries or hot fries — whatever you want to call them, they’re greasy, starchy, and a comfort food for many.

But reaching for those fried foods can have a negative impact on mental health.

A research team in Hangzhou, China found that frequent consumption of fried foods, especially fried potatoes, was associated with a 12 percent higher risk of anxiety and a 7 percent higher risk of depression than people who did not eat fried foods.

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The association was more pronounced among young men and younger consumers.

Fried foods are known risk factors for obesity, high blood pressure and other health effects. These findings “open a pathway to the importance of reducing fried food consumption for mental health,” according to the paper, published Monday in the journal PNAS.

But experts studying nutrition said the results are preliminary and it’s not necessarily clear whether the fried foods led to mental health problems or whether people with symptoms of depression or anxiety switched to fried foods.

The study evaluated 140,728 people over 11.3 years of age. After excluding participants diagnosed with depression within the first two years, a total of 8,294 cases of anxiety and 12,735 cases of depression were found among those who consumed fried foods, while fried potatoes in particular were found to have a 2 percent increased risk of depression was over roasted white meat.

The study also found that participants who regularly consumed more than one serving of fried food were more likely to be younger men.

“The human component of this study may show exactly what it suggests: that higher intake of fried foods increases risk of anxiety/depression,” said Dr. David Katz, a lifestyle medicine specialist who was not involved with the study, via email.

“However, the causal pathway could just as easily go the other way: people with anxiety/depression are increasingly turning to ‘comfort foods’ for some semblance of relief,” added Katz, founder of the nonprofit True Health Initiative, one global coalition of experts dedicated to evidence-based lifestyle medicine.

Those with underlying symptoms of anxiety and depression might turn to comfort foods as a means of self-treatment, he said.

Unhealthy eating and poor nutrition can lower mood and lead to a mental health condition, as noted in a previous study cited in this new one.

The same applies to zebrafish

In the new study, the researchers suspect that acrylamide, a chemical produced during roasting, primarily in fried potatoes, is responsible for the higher risk of anxiety and depression.

In a separate article referenced in the new study, the researchers exposed zebrafish to the chemical and found that long-term exposure had caused the fish to linger in dark zones within the tank, a common sign of a higher level of anxiety in the fish.

The zebrafish had also shown a reduced ability to explore their tanks and socialize because they did not swim closely with other zebrafish, although zebrafish are known to form schools with their species.

“Zebrafish were presumably chosen…because they were already known to be susceptible to acrylamide toxicity and because their behavioral responses to fear are established and consistent — they provide a source of both biological and behavioral data,” Katz said.

dr Walter Willett said the results “should be considered very preliminary, particularly the association with fried foods and acrylamide.”

“The health effects of fried foods are highly dependent on what foods are fried and the type of fat used to fry them,” Willett, a professor of epidemiology and nutrition at Harvard TH Chan School of Public Health, said via email. “Potatoes are a concern for potential mood effects because they can cause large spikes in blood sugar and then hormonal responses to those spikes. However, these fluctuations are partially blunted by fat that would be provided by the frying fat.”

Willett also noted that frying doesn’t just produce acrylamide. It’s in coffee because of the roasting of the beans and in toast because “heating carbohydrates along with protein can do it.”

He also said that the zebrafish data “are difficult to interpret in terms of human health because we’re obviously quite different, and the authors recognized that.”

Anxiety and depression on the rise

Zhejiang University researcher Yu Zhang, an author of the study, told CNN in an email that “there is no need to panic about the adverse effects of fried food.” But maintaining a healthy lifestyle and reducing your consumption of fried foods can be helpful for mental health in addition to overall health.

The researchers had pointed to a recent rise in depression and anxiety worldwide, with increases of 27.6 percent and 25.6 percent, respectively, in 2020. The World Health Organization also estimates that more than 5 percent of adults worldwide suffer from depression, according to the paper.

By examining the effects of fried food consumption in humans and acrylamide exposure in zebrafish, the researchers had compared the two to suggest that frequent consumption of the chemical commonly found in fried foods could have negative mental health effects.

According to Katz, a lack of variety in the diet also demonstrably reduces well-being.

“When a takeout is needed, it’s just that overall diet quality and healthy food choices are fundamental to every aspect of health – both mental and physical,” Katz said.

Willett said there’s also the possibility of reverse causality — that people may change their diet because they’re suffering from depression or anxiety. “These mood swings are generally more difficult to study because they can come and go, unlike the diagnosis of a major cancer or heart attack, the study in this analysis was not designed to address these challenges,” he said.