Building on the whole "healthy body, healthy mind" school of thought, it’s long been suggested that improving diets could help people stave off depression. While that promising claim needs further investigation, one thing is clear: just taking dietary supplements is not enough.
Recent research has shown that people who took daily nutritional supplements were just as likely to suffer from depression as those who took placebos. In short, the supplements appeared to have little to no effect on people’s mental health.
"Diet and nutrition held promise as one means to reach large numbers of people. However, this trial convincingly demonstrates that nutritional supplements do not help to prevent depression," Professor Ed Watkins, an expert in Experimental and Applied Clinical Psychology at the University of Exeter said in a statement.
"There was a suggestion that changing food-related behavior and diet may help to prevent depression, but this requires further investigation."
The results of the randomized clinical trial, part of the MooDFOOD trial, was reported this week in the Journal of the American Medical Association. An international team of scientists led by the University of Exeter in the UK took over 1,000 overweight or obese participants who were identified as being at elevated risk of depression and showed mild depressive symptoms but were not currently depressed.
Over the period of a year, half of them were given a placebo, while the other half were given a supplement containing folic acid, vitamin D, omega-3 fish oils, zinc, and selenium. Half of the people from each group also received behavioral therapy to help them snap out of their dietary behaviors and patterns.
After the year was up, an equal number of people in each group developed depression. In other words, nutritional supplements proved to be no better at warding of depression than the placebo. Lead author Mariska Bot from Amsterdam UMC added: “Therapeutic sessions aimed at making changes towards a healthy dietary behavior did also not convincingly prevent depression," although they did find some evidence that the therapies prevented depressive episodes in those participants who attended all of the recommended sessions.
That said, the link between a healthy diet and improved mental health is still showing some promise.
“A healthy dietary pattern, typified by a Mediterranean style diet high in fruit, vegetables, whole grains, fish, pulses and olive oil, and low in red meat and full-fat dairy products, may reduce the risk of developing depression,” noted MooDFOOD project coordinators Professor Marjolein Visser and Professor Ingeborg Brouwer of the Vrije Universiteit Amsterdam.
However, the team said further research is needed before any firm conclusions are settled on.