The evidence is mounting… what goes in our mouths plays a role in our moods particularly for anxiety and depressive symptoms.

In a world where mental health is gaining increasing attention, this research paper offers further insight into the question: Can what we eat affect how we feel?

Titled “The Effects of Dietary Improvement on Symptoms of Depression and Anxiety: A Meta-Analysis of Randomized Controlled Trials.,” this paper investigates the intricate relationship between diet and mental well-being, unveiling compelling insights into how our food choices might hold the key to alleviating depression and anxiety.

Trial effects on Clinical Depression

This study reviewed 16 randomised controlled trials with data from over 45,800 people.  Fifteen of the trials looked mostly at participants without clinical depression and only one had subjects with clinical depression. The outcomes of these studies showed an improvement in depressive symptoms when a dietary intervention was conducted. (Link to study below).

Clinical depression is reduced with an improved diet.
Lady eating fruit 2
Dietary improvement affects anxiety in women

Only 11 of the 16 studies looked at anxiety and the results were not as convincing. There was an interesting observation that women had the biggest improvement in anxiety with dietary interventions.

Dietary improvements most effective in clinically depressed

One of the things the study noted was that dietary improvements did not significantly alter the depressive scores for non-clinically depressed individuals. This is not a surprise as these individuals have less room for improvement compared to those who are clinically depressed.

Weight loss associated with improved depressive symptoms

Interestingly, weight loss interventions showed significant improvement in depressive scores. This is thought to be because of a reduction in inflammation that occurs with weight loss, rather than just a side effect of achieving weight loss goals. Other studies have found that improving the nutrition of a diet without weight loss can also improve major depressive disorders. This was demonstrated in a trial known as the SMILES trial conducted here in Australia. (Jacka et al., 2017). So the thought is that by improving the nutrient intake of participants, the inflammation decreased and thus the depressive symptoms.

Dietary improvements reduce inflammation. Inflammation affects mood and depression.

Clinical anxiety improved with dietary intervention

The study finishes off by making note that anxiety was not significantly reduced in this meta-analysis, but the studies that were used did not have participants with high levels of anxiety in general. One of the studies did have “borderline clinical anxiety” and that study did give a positive outcome with significantly reduced anxiety levels after a dietary intervention.

The best results were found with nutrition counselling from a nutrition professional

I will finish this summary by also noting that the best results in the trials that were analysed were found with those that had a nutrition professional such as a dietitian involved in the intervention. These had a small but significant positive effect on anxiety levels. What can I say?

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Firth, Joseph PhD; Marx, Wolfgang PhD; Dash, Sarah PhD; Carney, Rebekah PhD; Teasdale, Scott B. PhD; Solmi, Marco MD; Stubbs, Brendon PhD; Schuch, Felipe B. PhD; Carvalho, André F. MD; Jacka, Felice PhD; Sarris, Jerome PhD. The Effects of Dietary Improvement on Symptoms of Depression and Anxiety: A Meta-Analysis of Randomized Controlled Trials. Psychosomatic Medicine 81(3):p 265-280, April 2019. | DOI: 10.1097/PSY.0000000000000673

Jacka, F.N., O’Neil, A., Opie, R. et al. A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Med 15, 23 (2017).