'Anorexia of aging' occurs when healthy seniors experience a decrease in appetite and food intake. This often causes malnutrition in the elderly. The hormone leptin and the protein ghrelin help regulate body weight and appetite. Leptin is produced in fat cells and is known to produce feelings of satiety (fullness). Ghrelin is known to produce feelings of hunger, and increases during fasting and decreases after a meal. Now research reports that alterations in leptin and ghrelin in seniors can reduce hunger and increase feelings of satiety.
The study, published in the American Journal of Clinical Nutrition, examined how aging affects leptin and ghrelin levels as well as hunger and satiety feelings, in response to a meal. Researchers at the University of Verona, Italy, administered an 800 kilocalorie meal after an overnight fast to eight older men and women, ages 74 to 82 years old, and eight younger men and women, ages 25 to 38 years old. The participants' leptin, ghrelin and insulin levels were obtained before and after the meal.
The researchers found that feelings of fullness and the suppression of hunger lasted longer among the elderly participants, as compared to the younger group. The elderly group had higher leptin levels while fasting than the younger participants, although both groups had similar leptin levels after eating. The elderly subjects also had higher insulin levels after fasting and eating, than the younger group. However, both the elderly and younger participants had similar ghrelin levels during fasting and after eating.
"In healthy elderly, anorexigenic signals prevail over orexigenic signals, and they contribute to prolonged satiety and inhibition of hunger," the study authors conclude. "This condition may lead to a calorie deficit and finally to malnutrition in the elderly."
REFERENCES:
1. Di Francesco V et al. Unbalanced serum leptin and ghrelin dynamics prolong postprandial satiety and inhibit hunger in healthy elderly: another reason for the "anorexia of aging". Am J Clin Nutr 2006 May;83(5):1149-52.
Posted by Elaine Gavalas on August 26, 2006 12:33 PM
