Pilot study links reduction of ultra-processed foods with improvement in symptoms of depression and anxiety

The ultra-processed foods that flood shopping carts and supermarket shelves do not have positive effects on our body. Although they are usually cheap and quick options, their consequences are showing up in different spheres of our health. Beyond the damage to the body, there is also an impact on the mind and its diseases.

The journal JAMA Psychiatry has just published the first study that compares the symptoms of people with depression before and after they changed their usual diet of ultra-processed foods for a healthier diet. According to the authors, participants who reduced their consumption by more than 85% experienced moderate to significant improvements in three depression indicators. Anxiety levels were also slightly reduced.

These types of manufactured products include packaged snacks, fast food, sugary drinks and other industrially manufactured products that may contain preservatives, artificial colors, flavor enhancers and emulsifiers.

Although this was a pilot study that included only 20 people, it has served to “successfully establish the feasibility of carrying out this research in a larger-scale trial,” according to the lead author of the work, Andrew Krystal, Ray and Dagmar Dolby Distinguished Professor in the departments of Psychiatry and Behavioral Sciences and Neurology at the University of California, San Francisco (UCSF).

"Reducing the presence of these types of ultra-processed foods in our diet can be a challenge, since they are very appetizing, cheap and convenient," says Nyasha Chagwedera, author of the study and associate professor in the Department of Psychiatry and Behavioral Sciences at UCSF, who explains that they activate dopamine, the pleasure hormone, which promotes the desire to eat.

According to Chagwedera, founder of the UCSF Metabolic and Mental Health Program, the relationship between ultra-processed foods and depression could be explained by a leaky and unbalanced intestine, caused by the damage that these foods cause to the protective intestinal mucosa. "This intestinal damage can generate chronic low-grade inflammation throughout the body, which directly causes depression or increases vulnerability to it," he explains. In other words, overprocessing food can damage the gut in ways that impact the brain.

When evaluating the study, Carmen Romero Ferreiro, doctor in Biology and vice dean of Research at the Francisco de Vitoria University (UFV), in statements to SMC Spain, highlights that the work, unlike previous studies that have observed an association between a greater consumption of ultra-processed foods and a greater risk of depression, evaluates what happens when their consumption is reduced in people who already have this disorder.

The results are interesting, says Romero, because they open the possibility that diet has a complementary role in the management of depression. However, he clarifies, they should be interpreted with caution because this is a pilot study with a very small sample and changes in symptoms of depression and anxiety were not the main objective of the study. «In addition, it does not allow us to know if the results are specifically due to the reduction of ultra-processed foods or other associated changes in the diet, such as changes in the consumption of calories, fats or sugars. Therefore, larger studies will be necessary to confirm these results and better understand the mechanisms involved," adds the vice dean of the UFV.