Neurochemical alterations during age-related anorexia

Unexplained weight loss during the latter stages of aging is commonly prece ded by a spontaneous diminution in food intake. Multiple etiologies of age- related anorexia in humans, ranging from social isolation to impaired gastr ointestinal function, have been proposed. The observation of this phenomeno n in older laboratory animals suggests that physiological changes play a si gnificant causal role. A continually expanding body of information on the n eurochemical control of food intake supports a contribution of altered neur ochemistry to dysregulated feeding behavior. This review provides an update on the relationship between declining food intake during advanced age and physiological (specifically neurochemical) function. The complexity of the control of food intake as well as the variety of investigative methods used in this field of study render the identification of definitive causes diff icult. Evidence presented here is evaluated and possible etiologic factors are suggested.