Background: Anxiety and depression contribute to morbidity in elderly adults and may be associated with diet. We investigated the association between diet and psychological distress as a marker for depression.
Methods: Dietary patterns were defined by factor analysis or the Mediterranean Diet Score (MDS); depression and anxiety were assessed 12 years later. A total of 8,660 generally healthy men and women born in Australia and aged 50–69 years from the Melbourne Collaborative Cohort Study were included. At baseline (1990–1994), diet (food frequency questionnaire), education, Socio-Economic Indexes for Areas (SEIFA) – Index of Relative Socio-economic Disadvantage, medication use, social engagement, physical activity, smoking status, alcohol use, and health conditions were assessed; at follow-up (2003–2007), psychological distress was assessed using the Kessler Psychological Distress Scale (K10). Logistic regression was used to identify associations between diet and a K10 score ≥20, indicative of psychological distress.
Results: The MDS was inversely associated with psychological distress, with the odds ratio in the top-scoring group relative to the lowest scoring group being 0.72 (95% confidence interval = 0.54–0.95). Stronger adherence to a traditional Australian-style eating pattern was also associated with a lower K10 score at follow-up, with the odds ratio for having a K10 score indicative of psychological distress for the top 20% of adherence to this pattern relative to the lowest being 0.61 (95% confidence interval = 0.40–0.91).
Conclusions: A Mediterranean-style diet was associated with less psychological distress, possibly through provision of a healthy nutrient profile. The Australian dietary pattern, which included some foods high in fat and sugar content along with whole foods, also showed a weak inverse association. Adherence to this pattern may reflect a feeling of belonging to the community associated with less psychological distress.