The innate immune system of the brain is composed of microglial cells and astrocytes, which, once activated, produce proinflammatory cytokines. Proinflammatory cytokines act in the brain through specific receptors produced by brain cells and trigger behavioral modifications (sickness behavior) and cognitive and mood disorders. Aging-related neuroinflammatory processes are involved in neurodegenerative diseases. Polyunsaturated fatty acids (PUFAs) are essential nutrients provided by the diet that strongly regulate neuroinflammation and associated behavioral changes.