Nutrition-focused group intervention was not superior to social support in the treatment of depression: A randomized controlled trial with a strength-based counseling approach

• The multidimensional association between diet and depression is recognized. • This was a strength-based nutrition group intervention for people with depression. • The intervention did not impact depressive symptoms, life quality, or work ability. • Participants did not significantly improve their diet with the intervention. • Further research is needed to create an effective diet intervention for depression. Depression is a public health challenge, negatively affecting health and work ability. While an association between diet and depression is recognized, only a few randomized controlled trials have been published on the impact of diet counseling on clinical depression. We conducted an 8-week randomized controlled trial to examine the effectiveness of a strength-based, motivational nutrition group intervention on symptoms of depression among individuals with a moderate to severe major depressive disorder. Participants ( n = 93) were recruited from their healthcare units ( n = 13) in Kuopio and Siilinjärvi, Eastern Finland, and randomized into the intervention or control arm. Both arms attended six group sessions. The outcomes were assessed at baseline, 8 weeks, and 6 months using the Center for Epidemiological Studies Depression Scale (CES-D), the Index of Diet Quality (IDQ), the Assessment of Quality of Life – 8D (AQoL-8D), and a work ability indicator. In both groups, there were only non-significant improvements in depression symptoms, diet quality, quality of life, and work ability at 8 weeks and 6 months. Based on the AQoL subscales, mental health significantly improved in the intervention but not in the control group. There were, however, no significant differences between the groups in any outcomes. The results were similar at 8 weeks and 6 months. Blinding of the study participants was not possible. Only 55 % of the participants completed the follow-up at six months. The intervention was not effective in improving depression status or diet quality, in contrast to previous nutrition interventions for people with depression.