Nutrient patterns and depressive symptoms among Australian adults

Purpose: Much of the current literature on the associations between diet and depression focus on single nutrients rather than nutrient patterns (NPs). We investigated the association between NPs and depressive symptoms (DepS) in an Australian adult population. Methods: DepS were examined at two different time points, in 2010 (Stage 3, n = 1743, 49.0% males) and 2015 [North West 2015 (NW15), n = 1,024, 46.6% males] of the North West Adelaide Health Study (NWAHS). Dietary habits were evaluated using a food frequency questionnaire (FFQ) at Stage 3. DepS were assessed using the Center for Epidemiological Studies Depression (CES-D) scale at Stage 3 and NW15. Principal component analysis was used to identify NPs as well as the factor structure of the CES-D. Log- and negative binomial regression analyses were used to assess the association between NPs and DepS scores. Ordinal logistic regression analysis was undertaken between the NPs and identified factors of the CES-D score. Results: Three NPs (from the FFQ) and two-factors (from the CES-D score) were obtained. After adjusting for known confounding variables, a ‘plant-sourced’ NP (β-carotene, fibre, vitamin C, potassium and α-carotene) was inversely associated with DepS at Stage 3 [prevalence ratio (PR), 0.78; 95% CI 0.66–0.92; p = 0.003], whereas an ‘animal-sourced’ (ω-3 fatty acid, monounsaturated fat, vitamin E and cholesterol) or ‘mixed-source’ (phosphorous, protein, vitamin B2, iodine and zinc) NP was not associated with DepS. There was an inverse relationship between the ‘plant-sourced’ NP and the ‘(absence of) positive-affect’ factor from the CES-D in both stages. Conclusion: The ‘plant-sourced’ NP is consistently and inversely associated with DepS; however, longitudinal studies are recommended to confirm these results.