Anorexia and aging: pathophysiology.

Aging results in a dysregulation of the ability to regulate food intake. In general, this presents as a decrease in food intake accompanied by early satiation. The early satiation appears to be predominantly due to a decrease in adaptive relaxation of the fundus of the stomach resulting in early antral filling. Increased levels and effectiveness of cholecystokinin also play a role in the anorexia of aging. Leptin levels increase with aging in males but not in females. With regard to the central feeding drive, both the opioid and neuropeptide Y effects appear to decline with age. This physiologic anorexia of aging increases the risk for older persons to develop severe anorexia and weight loss when disease occurs.