LEPTIN LEVELS RECOVER NORMALLY IN HEALTHY OLDER ADULTS AFTER ACUTE DIET-INDUCED WEIGHT LOSS

Objectives: Involuntary weight loss affects 20% of community dwelling older adults. The underlying mechanism for this disorder is unknown. Objective is to determine if failure of older persons to regain weight is associated with elevated pro-inflammatory cytokine and leptin levels. Design: Prospective diet intervention study. Setting: University of Washington Medical Center from 2001-2005. Participants: Twenty-one younger (18-35 years old) and nineteen older (≥ 70 years old) men and women. Intervention: Each subject was placed for two weeks on a weight-maintaining diet, followed in sequence by 2 weeks of 30% caloric restriction, then 4 weeks of ad libitum food intake. Measurements: Plasma leptin levels, fasting serum pro-inflammatory cytokine levels, and peripheral blood mononuclear cell cytokine levels were measured. Results: Leptin levels in the two cohorts decreased after caloric restriction and increased after ad-libitum food consumption resumed. Plasma TNF α levels were higher in older subjects compared to younger adults. However, there was no association between changes in TNF α levels and changes in AUC leptin. Conclusion: Leptin levels in healthy older individuals responded appropriately in a compensatory manner to changes in body weight. These data do not support a cytokine dependent elevation in leptin levels as being responsible for the failure of older adults to regain weight