The present invention is related to mammalian nutrition and effects thereof in individuals with age associated cognitive decline such as Age Associated Memory Inpairment (AAMI) or a dementing illness such as Alzheimer's disease or related dementia, or Mild Cognitive Impairment, such as improving performance in, or reversal, prevention, reducing and delaying decline in, one or more of cognitive function, memory, behavior, cerebrovascular function, motor function, and/or brain physiology are seen. In particular, the present invention utilizes medium chain triglycerides, in one embodiment, administered as part of a long-term treatment regimen, to preserve or improve learning, attention, motor performance, cerebrovascular function, social behavior, and to increase activity levels, particularly in aging mammals.