quinta-feira, outubro 29, 2009
A idade do seu coração depende, em parte, de quanto você come
New Insights Into Cardiac Aging
Anthony J. Muslin, MD
From the Center for Cardiovascular Research, Washington University School of Medicine, St Louis, Mo.
All animals have limited life spans, and work in a variety of organisms has established that caloric restriction results in increased longevity. For example, inbred female mice fed an ad libitum diet had an average life span of 27 months, whereas calorie-restricted mice fed a diet with 65% fewer calories had an average life span of 45 months.1 The mechanisms by which caloric restriction retards aging and promotes longevity are likely manifold, but reduced insulin action in various tissues is a well-accepted mechanism of this phenomenon. Indeed, in the nematode Caenorhabditis elegans, a loss-of-function mutation in the insulin receptor-like gene daf-2 significantly promoted longevity.2 In mice, generalized overexpression of the insulin/insulin-like growth factor signaling inhibitor Klotho resulted in animals that had significantly increased longevity and reduced insulin sensitivity.3 In addition, tissue-specific targeted disruption of the insulin receptor gene in the adipose tissue of mice led to significantly increased life span.4
Em laboratório, quem come menos, vive mais do que quem come a vontade, mesmo sem obesidade.
Seria isso verdade para os humanos?
Parece que a insulina, e sua sinalização celular, tem a ver com esse envelhecimento.
Quanto mais comemos, mais insulina, maior o envelhecimento?