Dr Tim Crowe 1

Nutrition research can make for attention-grabbing headlines. Here, we cut through the hype – and clarify the real take-home message – for you.

Eating yourself happy

Food nourishes the body and mind, so could an effective way to manage depression be found in your kitchen? New research has provided a tantalising hope that dietary changes may go some way to keeping the black dog at bay.

Food and mood reside on a two-way street. Our diet can affect our mood and our mood can equally affect our food choices. A healthy diet is a common feature linked to a positive mental outlook, but the problem with most of the observational research validating this link is that it is hard to tease out which comes first. Are people in the depths of depression more likely to eat poorly because of their mood? Or does a poor diet exacerbate depressive symptoms? Now the first dietary intervention study of its kind has found positive dietary changes to be beneficial in helping treat moderate to severe depression, opening up the door for diet therapy to be part of the treatment spectrum.


The hype: How the media conveyed the news

The research garnered much media attention because it ticked many boxes to make it a newsworthy item. Mediterranean diet can help in fight against depression, Australian study finds (ABC News), Mediterranean diet can beat depression, research suggests (SBS News) and World’s first clinical trial finds diet works for depression (Psychology Today).

The media spotlight was on the novel world-first aspect of the research, which was supported by the well-regarded research team lead by Professor Felice Jacka from Deakin University, who already have a high profile on the area of diet and mood. In any one year, around 1 million Australian adults have depression so research that offers another avenue to treat this condition will get a lot of public attention. The media seemed to get the tone right in their coverage in balancing the novelty of the findings against this being a single study of small numbers and short duration. The key takeaway from the coverage was that diet may help with depression, but it is not a replacement for current therapies.


The truth: The research findings

The study (aptly called the SMILES study – Supporting the Modification of Lifestyle In Lowered Emotional States) involved 67 people with moderate to severe depression. Those in the dietary treatment group received seven 60-minute sessions of dietary counselling. The control group received matching social support contact, but no specific dietary advice. Almost all the participants were receiving another active treatment such as psychotherapy, medications, or both.

The dietary counselling sessions were about getting people to eat more in line with dietary advice aligned with a modified form of the Australian Dietary Guidelines and Dietary Guidelines for Adults in Greece. So there was a distinctly Mediterranean flavour to the advice. Wholegrains, fruits, vegetables, nuts and legumes, and lean meats, chicken, and seafood were on the menu and highly refined starches, sugar and highly processed foods were shunned.

After 12 weeks, there was a statistically significant improvement in the rating scale of depression used in favour of the dietary treatment group. A range of secondary measures looking at mood and wellbeing were all pointing in a positive direction. The benefit of diet on depression was independent of any changes in body weight, self-efficacy, smoking rates or physical activity.

A strength of the study was including a control group that received an equal level of social support from the research team. Social support can improve depression so it is important to disentangle this from the effect of dietary changes.

The study was small in size, but with very good compliance and completion rates. The fact that the dietary intervention group could make significant improvements to their diet quality suggests that dietary improvement is achievable for those with clinical depression despite the fatigue and lack of motivation that are prominent symptoms of this disorder.


The reality: Putting the findings into practice

This is the first published randomised-controlled trial to explicitly seek to answer the question: if I improve my diet, will my mental health improve? The results suggest that improving one’s diet may be a useful and accessible strategy for addressing depression as part of a larger treatment plan. In the media coverage given to the research and comments made by the lead researcher Professor Felica Jacka, there was support given for dietitians being part of mental health care teams and making dietitian support available to those experiencing depression. Considering the wealth of health benefits already linked to a Mediterranean-style dietary pattern, then this new research gives more credence for individualising dietary advice to the public to align closer with this.


Tim is an Advanced Accredited Practising Dietitian, and career nutrition research scientist and media communicator. Connect with him at www.thinkingnutrition.com.au

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