- A small pilot study found improvements in depression symptoms after participants reduced ultra-processed foods.
- Participants cut their ultra-processed food intake by 85% and saw some reduction in symptoms of depression.
- Other research has shown a growing concern with ultra-processed food and how it might adversely impact health.
Add this to the list of ills that might be linked to eating ultra-processed foods: A small UC San Francisco pilot study suggests that cutting back on ultra-processed foods may help improve depression symptoms, although larger trials are needed to confirm the findings.
Read more Talks fall apart on bipartisan deal to ease energy costs, expedite permitting process
The study, published this week in the peer-reviewed journal JAMA Psychiatry, compared the symptoms of people with depression before and after they changed their diets to cut back ultra-processed foods in favor of healthier choices. The research was funded by the National Institutes of Health.
It was a very small study, involving just 20 people, but “successfully established the viability of carrying out this research in a larger-scale trial,” said senior author Dr. Andrew Krystal, a professor in UCSF’s departments of Psychiatry and Behavioral Sciences and Neurology.
Per a news release, “Participants reduced ultra-processed food intake by more than 85% and experienced moderate to large improvements across three measures of depression. Anxiety scores also improved modestly.”
The university plans to enroll participants in a much larger follow-up study in 2028.
What are ultra-processed foods?
Ultra-processed foods make up a huge portion of the typical American diet, as Deseret News has previously reported. And that’s a challenge that the federal government’s new dietary food guidelines have tried to tackle. As Deseret News reported, “Red meat and dairy are in. Saturated fats came off the naughty list, though people were told to reduce them to at most 10% of daily calories. Grains were somewhat de-emphasized. And not surprisingly, ultra-processed foods and refined carbohydrates got a big thumbs down.”
As The Washington Post explained, “Ultra-processed foods encompass a broad category ranging from cookies, doughnuts and potato chips to hot dogs, white bread and frozen meals. Scientists say what these foods have in common is that they are typically formulations of industrial ingredients that are designed by manufacturers to achieve a certain ‘bliss point,’ which causes us to crave and overeat them. They also tend to be low in nutrients such as fiber, vitamins and minerals.”
Snacks including cookies and chips, fast food, sugary beverages, many frozen microwave-ready meals, loads of shelf-stable food items and more fall into the category, often packed with preservatives, artificial coloring, flavor enhancers and emulsifiers, as the researchers note. Ultra-processed foods typically contain little or no whole foods.
Ultra-processed foods are a staple in part because they taste good, are cheap and convenient, according to Dr. Nyasha Chagwedera, assistant professor in the UC San Francisco’s Department of Psychiatry and Behavioral Sciences. The release quoted her: “Ultra-processed food triggers dopamine, the pleasure hormone, which promotes craving. Food companies work with scientists to find just the right amount of sugar, salt, and fat that make you want to eat more and more.”
Some ultra-processed foods are healthy, such as those containing whole grains.
Study basics
All the participants in the study had depression, but most of them also had anxiety and all had a high body mass index (BMI) and at least one metabolic disorder such as hypertension, diabetes or high cholesterol. Seventy percent were female and the average age was 44.
They were each assigned to one of two groups. One followed their usual diet for four weeks, but the other changed to a low ultra-processed food diet, which they shopped for on their own with some guidance from the researchers. After four weeks, the groups switched diets.
It could be that ultra-processed food and depression are linked by a “leaky, out-of-balance gut,” from damage the food causes to the gut’s protective lining, said Chagwedera, who founded the university’s Metabolic and Mental Health Program. “This gut damage can create low-grade, chronic inflammation throughout the body that either directly causes depression or makes people more vulnerable to it.”
She added: “In other words, the junky processing may harm your gut in ways that ripple up to your brain.”
Read more Jazz and Mammoth owner Ryan Smith talks Steve Ballmer, sports betting and NIL donations
Ultra-processed foods and bad health outcomes
The federal government has been calling out the potential harms of ultra-processed foods as a dietary staple, noting the importance of focusing a diet on whole foods when possible.
Per the U.S. Food and Drug Administration, “The U.S. faces a growing epidemic of preventable diet-related chronic diseases, such as cardiovascular disease, type 2 diabetes and obesity. Researchers have found links between the consumption of highly processed foods (commonly called ultra-processed foods, or UPFs) and a range of negative health outcomes, including cardiovascular disease, obesity and certain cancers. It is estimated that 70% of the U.S.packaged food supply is comprised of foods commonly considered ultra-processed, and that children get over 60% of their calories from such foods.”
Ultra-processed foods have been extensively studied for their impact on health outcomes.
For instance, a review of mega analyses in 2024, published in the journal BMJ, concluded that “diets high in ultra-processed food may be harmful to many body systems.”
The analysis, which involved researchers from Australia, France, Ireland and the U.S., found some level of evidence for 32 adverse health outcomes spanning “mortality, cancer and mental, respiratory, cardiovascular, gastrointestinal and metabolic health outcomes.”
Per a Deseret News article, “The team found ‘convincing evidence’ of direct links to consuming a lot of ultra-processed food and all-cause and heart-disease-related mortality, Type 2 diabetes, overweight and obesity, as well as anxiety and other common mental health challenges.
Also in 2024, Deseret News reported on a study led by Harvard T.H. Chan School of Public Health involving more than 74,500 female nurses in 11 states who took part in the Nurses’ Health Study from 1984-2018 and 39,501 men from all 50 states who were part of the Health Professionals Follow-up Study, 1986-2018. None had a history of diabetes, heart disease or cancer when the study began.
Researchers found an association between eating ultra-processed food and mortality. It was stronger when individuals also drank distilled alcoholic beverages.
“Importantly, the authors also looked at diet quality. They found that for people who had high quality diets (high in fruit, vegetables, whole grains, as well as healthy fats, and low in sugary drinks, salt, and red and processed meat), there was no clear association between the amount of ultra-processed food they ate and risk of premature death,” as The Conversation reported of the study.
Other studies that year said men face a greater risk of colon cancer if they consume a lot of ultra-processed foods and that both men and women have increased risk of heart disease.
Marion Nestle, who has written books about food politics and marketing, told CNN that there are “literally hundreds of studies” that find a link between consumption of ultra-processed foods and obesity, cancer, cardiovascular disease and overall death.