Background. Major depression affects over 15 million Americans in a given year. While research supports that diet results in better physical health, less is known about the affect of dietary patterns on mental health, specifically depression.

Objective. This study investigates the relationship between dietary pattern quality and reported symptoms of depression.

Subjects/setting. Subjects included 1,118 low-income adults, aged 30-64 years, living in Baltimore City and participating in the initial examination and recruitment phase of the Healthy Aging in Neighborhoods of Diversity across the Life Span study, conducted between October 2004 and January 2008.

Methods. Nutrition data were based on the average of two 24-hour dietary recalls collected by trained interviewers using the USDA Automated Multiple Pass Method. Dietary pattern quality was calculated using a micronutrient index, a modified Healthy Diet Indicator, and the USDA's Healthy Eating Index-2005. Depressive symptoms were assessed by a trained interviewer using the Center for Epidemiologic Studies Depression scale.

Statistical analysis. Linear regression analysis was used to examine whether or not dietary pattern quality was associated with depressive symptoms.

Results. A diet in accordance with current dietary guidelines was significantly associated with fewer depressive symptoms (HDI-Am p-value = 0.0314; HEI-2005 p-value < 0.0001; Micronutrient Index p-value = 0.0001). After accounting for gender, race, age, education, income, and participation in food assistance programs, socioeconomic status (education and income) was found to have a stronger affect on depressive symptoms than diet quality alone. Differences between dietary pattern qualities of males and females reporting symptoms of depression were inconsistent. There were significant racial differences between dietary pattern qualities of individuals reporting depressive symptoms (HEI-2005 p-value = 0.0019; Micronutrient Index p-value = 0.0076).

Conclusion. To our knowledge, this is the first analysis examining the relationship between dietary pattern quality, using multiple indices, and reported symptoms of depression in a low-income, American population. Future studies are needed to investigate possible mediator effects of diet quality and depression.