A small preliminary study shows that reducing ultra-processed foods such as industrial snacks, fast food and sugary drinks can reduce anxiety and depressive symptoms: at the center of the phenomenon is intestinal health.
Could a healthier diet less rich in ultra-processed foods alleviate mood disorders? The question is complicated, given the scale of the challenge, but if reducing hyper-processed foods, designed to make us “never want to stop” consuming them, improved mental health, it would be a great reason to try.
A small preliminary study from the University of California at San Francisco compared the symptoms of people suffering from depression before and after a drastic change in their diet, initially rich in ultra-processed foods and then healthy. The results, published on JAMA Psychiatryare encouraging.
A month without ultra-trials
The study involved only 20 participants, but explored the possibility of expanding the survey to a larger sample in the future. The participants, with an average age of 44 years, were 70% women, all with a high body mass index and with at least one metabolic disorder including diabetes, hypertension or high cholesterol. All subjects suffered from depression and 14 also from anxiety.
Half of the group continued to follow the usual diet, while the other half had to reduce the amount of ultra-processed foods put on the table by 85%: pre-packaged snacks, sugary drinks, fast food and industrial foods rich in dyes, emulsifiers, preservatives and flavor enhancers disappeared from the shopping, and the participants were able to do the shopping on their own, choosing healthy products under the guidance of an expert. After four weeks, the two groups switched diets.
A lighter load: does the intestine have anything to do with it?
The reduction in ultraprocessing brought with it moderate to significant improvements in three parameters used to evaluate depression, and anxiety, in those who suffered from it, was also partially attenuated. There are too few participants to reach clearer conclusions, but these initial results have encouraged researchers to plan a phase 2 study, which will be conducted in 2028.
A working hypothesis is that the possible alleviation of mood disorders may result from improved intestinal health. A poor diet can alter the intestinal barrier (the set of cells, microorganisms, enzymes, hormones and blood vessels that protects the intestine) and make it permeable.
In this condition, the junctions between cells in the intestinal wall become loose, and small fragments or products of intestinal bacteria or toxins can pass from the intestine into the bloodstream. According to the authors, this damage could generate, over time, chronic inflammation that could make you more vulnerable to depression or contribute to it.
