A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial)

Abstract

BackgroundThe possible therapeutic impact of dietary changes on existing mental illness is largely unknown. Using a randomised controlled trial design, we aimed to investigate the efficacy of a dietary improvement program for the treatment of major depressive episodes.Methods‘SMILES’ was a 12-week, parallel-group, single blind, randomised controlled trial of an adjunctive dietary intervention in the treatment of moderate to severe depression. The intervention consisted of seven individual nutritional consulting sessions delivered by a clinical dietician. The control condition comprised a social support protocol to the same visit schedule and length. Depression symptomatology was the primary endpoint, assessed using the Montgomery–Åsberg Depression Rating Scale (MADRS) at 12 weeks. Secondary outcomes included remission and change of symptoms, mood and anxiety. Analyses utilised a likelihood-based mixed-effects model repeated measures (MMRM) approach. The robustness of estimates was investigated through sensitivity analyses.ResultsWe assessed 166 individuals for eligibility, of whom 67 were enrolled (diet intervention, n = 33; control, n = 34). Of these, 55 were utilising some form of therapy: 21 were using psychotherapy and pharmacotherapy combined; 9 were using exclusively psychotherapy; and 25 were using only pharmacotherapy. There were 31 in the diet support group and 25 in the social support control group who had complete data at 12 weeks. The dietary support group demonstrated significantly greater improvement between baseline and 12 weeks on the MADRS than the social support control group, t(60.7) = 4.38, p < 0.001, Cohen’s d = –1.16. Remission, defined as a MADRS score <10, was achieved for 32.3% (n = 10) and 8.0% (n = 2) of the intervention and control groups, respectively (χ 2 (1) = 4.84, p = 0.028); number needed to treat (NNT) based on remission scores was 4.1 (95% CI of NNT 2.3–27.8). A sensitivity analysis, testing departures from the missing at random (MAR) assumption for dropouts, indicated that the impact of the intervention was robust to violations of MAR assumptions.ConclusionsThese results indicate that dietary improvement may provide an efficacious and accessible treatment strategy for the management of this highly prevalent mental disorder, the benefits of which could extend to the management of common co-morbidities.Trial registrationAustralia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12612000251820. Registered on 29 February 2012.

The Association between Dietary Quality and Dietary Guideline Adherence with Mental Health Outcomes in Adults: A Cross-Sectional Analysis

“…Thus future prospective cohort studies and controlled trials examining the potential of increasing dietary quality for improving mental health and well-being are warranted. Indeed recent data from the SMILES trial (a randomized controlled trial of dietary improvement for adults with major depression) are very encouraging as they provide the first preliminary evidence that personalised one-to-one dietary counseling may be a suitable option to consider in the delivery and management of individuals with adverse mental health disorders [57]. Future nutritional psychiatry research should aim to replicate and confirm these findings.…”

Focus on fatty acids in the neurometabolic pathophysiology of psychiatric disorders

“…Several dietary trials are underway in psychiatric disorders, some already show potential of dietary modification, including increasing omega-3 fatty acid intake, e.g., from nuts and fish (Berk et al 2013;Sarris et al 2015;Opie et al 2016). For example, in depression, a relatively well-conducted 12-week single blind randomized controlled trial of an adjunctive dietary intervention vs. a social support protocol showed a number needed to treat of 4.1 for remission (Jacka et al 2017). Moreover, combining increased dietary omega-3 fatty acid intake with other dietary and lifestyle factors decreasing oxidative stress, e.g., physical exercise, seems particularly promising (Gomez-Pinilla 2011; Berk et al 2013;Daumit et al 2013;Roca et al 2016;Naslund et al 2017).…”

A low-carbohydrate survey: Evidence for sustainable metabolic syndrome reversal

“…107,108 Antidepressant medications also carry significant side effects, especially in elderly patients already under a burden of iatrogenic polypharmacy. 109 Our survey respondents reported marked improvements in symptoms of anxiety and depression after starting a low-carbohydrate diet.…”