Reprinted from an article in Science Tech Daily, May 26, 2022

Young men with a poor diet saw a significant improvement in their symptoms of depression when they switched to a healthy Mediterranean diet, a new study shows.

Depression is a widespread mental health issue that affects roughly 300 million people globally each year. It is a substantial risk factor for suicide, the largest cause of mortality among young people. The 12-week randomized controlled trial, conducted by experts from the University of Technology Sydney, was recently published in the peer-reviewed American Journal of Clinical Nutrition.

According to lead researcher Jessica Bayes, a Ph.D. candidate at the UTS Faculty of Health, the study was the first randomized clinical trial to examine the influence of a Mediterranean diet on depressive symptoms in young males (aged 18 to 25).

“We were surprised by how willing the young men were to take on a new diet,” Bayes said. “Those assigned to the Mediterranean diet were able to significantly change their original diets, under the guidance of a nutritionist, over a short time frame.”

“It suggests that medical doctors and psychologists should consider referring depressed young men to a nutritionist or dietitian as an important component of treating clinical depression,” she said.

The link between food and mood

The research contributes to the emerging subject of nutritional psychiatry, which seeks to investigate the impact of particular nutrients, foods, and dietary patterns on mental health. The study’s diet was rich in colorful vegetables, legumes, and whole grains, as well as oily fish, olive oil, and raw, unsalted nuts.

“The primary focus was on increasing diet quality with fresh whole foods while reducing the intake of ‘fast’ foods, sugar, and processed red meat,” Bayes said. “There are lots of reasons why scientifically we think food affects mood. For example, around 90 percent of serotonin, a chemical that helps us feel happy, is made in our gut by our gut microbes. There is emerging evidence that these microbes can communicate to the brain via the vagus nerve, in what is called the gut-brain axis.”

“To have beneficial microbes, we need to feed them fiber, which is found in legumes, fruits, and vegetables,” she said.

Roughly 30 percent of depressed patients fail to adequately respond to standard treatments for major depressive disorder such as cognitive behavioral therapy and antidepressant medications. “Nearly all our participants stayed with the program, and many were keen to continue the diet once the study ended, which shows how effective, tolerable, and worthwhile they found the intervention,” Bayes concluded.

Reference: Bayes J, Schloss J, Sibbritt D. The effect of a Mediterranean diet on the symptoms of depression in young males (the AMMEND study): a randomized controlled trial. Am J Clin Nutr. 2022;116(2): 572-580. doi:10.1093/ajcn/nqac106