Sci. Aging Knowl. Environ., 3 October 2001
Effects of Food Restriction on Aging: Separation of Food Intake and Adiposity
David E. Harrison, Jonathan Archer, and Clinton M. Astlehttp://sageke.sciencemag.org/cgi/content/abstract/sageke;2001/1/cp3
Abstract: Restricted feeding of rodents increases longevity, but its mechanism of action is not understood. We studied the effects of lifelong food restriction in genetically obese and normal mice of the same inbred strain in order to determine whether the reduction in food intake or the reduction in adiposity (the percentage of fatty tissue) was the critical component in retarding the aging process. This was possible because food-restricted obese (ob/ob) mice maintained a high degree of adiposity. In addition to determining longevities, changes with age were measured in collagen, immune responses, and renal function. Genetically obese female mice highly congenic with the C57BL/6J inbred strain had substantially reduced longevities and increased rates of aging in tail tendon collagen and thymus-dependent immune responses but not in urine-concentrating abilities. When their weight was held in a normal range by feeding restricted amounts, longevities were extended almost 50%, although these food-restricted ob/ob mice still had high levels of adiposity, with fat composing about half of their body weights. Their maximum longevities exceeded those of normal C57BL/6J mice and were similar to the longevities of equally food-restricted normal mice that were much leaner. Food-restricted ob/ob mice had greatly retarded rates of collagen aging, but the rapid losses with age in splenic immune responses were not mitigated. Thus, the extension of life-span by food restriction was inversely related to food consumption and corresponded to the aging rate of collagen. These results suggest that aging is a combination of independent processes; they show that reduced food consumption, not reduced adiposity, is the important component in extending the longevity of genetically obese mice.
Reproduced by permission.
David E. Harrison, Jonathan Archer, Clinton M. Astle, Effects of Food Restriction on Aging: Separation of Food Intake and Adiposity. Proc. Natl. Acad. Sci. U.S.A. 81, 1835-1838 (1984).
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