Healthy diet reduces depression symptoms in young adults: PLOS ONE

Australia: Consumption of a healthy diet may reduce depression symptoms in young adults with depression, finds a recent study published in the journal PLOS ONE. These findings add to a growing literature showing a modest change to diet is a useful adjunct therapy to reduce depression symptoms.

People worldwide are increasingly consuming a diet rich in saturated fats, processed foods and refined sugars. The literature strongly suggests that poor diet quality may increase depression risk. Diet is, therefore, a modifiable risk factor for depression which would be a good target for early intervention. But there is no convincing evidence for a causal relationship between diet quality and depression, particularly in young adults.

Heather M. Francis, Macquarie University, Australia, and colleagues conducted the study to i) to investigate whether young adults with elevated depression symptoms would comply with a brief, 3-week diet intervention, ii) whether this can improve symptoms of depression; and iii) whether compliance to the diet would be associated with improvement in depression symptoms.

The researchers studied 76 university students (17-35 years old) exhibiting moderate-to-high depression symptoms and following a poor diet based on the Australian Guide to Healthy Eating (high in processed foods, sugar, and saturated fats). They randomized participants into a “diet change” group or a “regular diet” group. The diet change group was given brief instructions on improving their diet, as well as a healthy food hamper and $60 towards future groceries. Each group member also received two subsequent check-ins via phone call. The regular diet group did not get any diet instructions and were simply asked to return after the three weeks were up. Before and after the intervention, the researchers assessed participants’ scores for depression, anxiety and overall mood, and their performance on several learning and reasoning tasks.

Key findings of the study include:

• There was good compliance with the diet intervention recommendations assessed using self-report and spectrophotometry.


• At the end of the three weeks, the diet change group had successfully maintained a healthy diet and showed significant improvement in mood, with depression scores shifting into the normal range.


• The regular diet group’s depression scores remained stable in the moderate-to-high range.


• The diet change group also showed significantly lower anxiety scores than the regular diet group, though other measures were not significantly different between the groups.


• The authors followed up with 33 of the participants after three months. In this small sample, they found that while only 21 percent of these participants fully maintained the healthy diet, those that did maintained their improvements in mood.

The authors concluded "The current intervention involved such a small degree of face-to-face contact and very little cost or risk, thus there are few downsides to adopting this approach to improving mood. Conversely, there is a lot to gain not just in terms of improvements to mood but also in enhanced physical health outcomes."

“Modifying diet to reduce processed food intake and increase consumption of fruit, vegetables, fish and olive oil improved depression symptoms in young adults. These findings add to a growing literature showing a modest change to diet is a useful adjunct therapy to reduce symptoms of depression," concluded the authors.

More information: "A brief diet intervention can reduce symptoms of depression in young adults – A randomised controlled trial" published in PLOS ONE.

DOI: https://doi.org/10.1371/journal.pone.0222768

Journal Information: PLOS One