Men with depression saw their symptoms significantly improve after switching to a Mediterranean diet, a new study reports.
The trial studied the impact of a Mediterranean diet on men aged 18 to 25 with depression and a poor diet.
Its findings suggest doctors and psychologists should think about referring depressed young men to nutritionists or dieticians, said University of Technology Sydney researchers.
The study focussed on increasing diet quality with fresh 'whole foods' and reducing 'fast' foods, sugar and processed red meat.
Participants ate a diet rich in colourful vegetables, legumes and whole grains, oily fish, olive oil and raw, unsalted nuts.
The study contributes to the emerging field of nutritional psychiatry that explores the effect specific nutrients, foods and dietary patterns can have on mental health.
Depression is a common mental health condition and the study notes it affects approximately one million Australians each year.
It is a significant risk factor for suicide, the leading cause of death in young adults.
Nutritionists guided the young men through their diet change during the 12-week randomised control trial.
Lead researcher Jessica Bayes, a PhD candidate in the UTS Faculty of Health, said the study was the first randomised clinical trial to assess the impact of a Mediterranean diet on the symptoms of depression in young men (aged 18-25).
Bayes said: "We were surprised by how willing the young men were to take on a new diet."
"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."
Regarding the diet used in the study, Bayes said: "The primary focus was on increasing diet quality with fresh whole foods while reducing the intake of 'fast' foods, sugar and processed red meat.
"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."
She explained: "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 fibre, which is found in legumes, fruits and vegetables."
Roughly 30 percent of depressed patients fail to adequately respond to standard treatments for major depressive disorder such as cognitive behaviour 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."
The trial was recently published in the peer-reviewed medical journal American Journal of Clinical Nutrition.
