Background: Depression is common in older adults and more prevalent in those with cognitive impairment, vascular risk factors, or stroke. Nonpharmacologic strategies to reduce depression, such as diet, may be effective; however, few studies have investigated the relation.

Methods: A total of 709 participants (23.3% men, mean age 80.4), from an observational prospective cohort study were assessed annually for an average of 6.53 years of follow-up. Participants with missing or invalid baseline dietary evaluations or fewer than two depression assessments were excluded. Depressive symptoms were assessed with a 10-item version of the Center for Epidemiologic Studies Depression scale. High burden of depressive symptoms was defined as the presence of four or more depressive symptoms. Diet scores were computed using a validated food frequency questionnaire for the Dietary Approaches to Stop Hypertension (DASH) diet, Mediterranean diet, Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, and Western diets. Diet scores were modeled in tertiles. A generalized estimating equation (GEE) model was performed for the longitudinal analysis of depression as a binary outcome.

Results: Participants in the highest tertile of the DASH (β = -0.10, confidence interval [CI]: -0.20, -0.0064) and MIND (β = -0.12, CI: -0.23, -0.0092) diet scores had lower rates of depressive symptoms over time when compared to those in the respective lowest tertiles. The Western diet was positively associated with depressive symptoms over time (β = 0.093, p-trend = .05).

Conclusions: Diet may be effective in reducing depressive symptoms in older adults. A diet intervention trial may be needed to determine the optimal nutritional components for prevention of late onset depression.