The invention provides compositions comprising one or more long chain polyunsaturated fatty acids, nitric oxide releasing compounds, and medium chain triglycerides and methods for using such compositions for enhancing cognitive function, reducing or preventing a decline of social interaction, reducing or preventing age-related behavioral changes, increasing trainability, maintaining optimal brain function, facilitating learning and memory, reducing memory loss, retarding brain aging, preventing or treating strokes, and preventing or treating dementia in an animal. Preferably, the compositions are food compositions useful for enhancing cognitive function in humans and companion animals.