Objective: To evaluate the relation between nutrient intake and psychiatric functioning in adults with confirmed mood disorders. Method: A cross-sectional study was conducted of the intake of major (that is, carbohydrates, fat, and protein) and minor (that is, vitamins and minerals) nutrients (from 3-day food records and a Food Frequency Questionnaire), Global Assessment of Functioning (GAF) scores, and symptoms of depression and mania (the Hamilton Depression Rating Scale and the Young Mania Rating Scale) in 97 community-based adults with mood disorders whose diagnoses were confirmed with structured interviews. Results: Significant correlations were found between GAF scores and energy (kilocalories), carbohydrates, fibre, total fat, linoleic acid, riboflavin, niacin, folate, vitamin B6, vitamin B12, pantothenic acid, calcium, phosphorus, potassium, and iron (all P values < 0.05), as well as magnesium (r = 0.41, P < 0.001) and zinc (r = 0.35, P < 0.001). Though modest in magnitude, the pattern of correlations was consistent, indicating higher levels of mental function associated with a higher intake of nutrients. Depression and mania scores, which were generally mild or moderate, did not individually show consistent patterns. When dietary supplement use was added to nutrient intakes from food, GAF scores remained positively correlated (P < 0.05) with all dietary minerals. Conclusion: This detailed analysis in a clinically diagnosed sample was consistent with prior epidemiologic surveys, revealing an association between higher levels of nutrient intakes and better mental health. Nutrient intakes warrant further consideration in the treatment of people with mood disorders.