Leanness vs. CR for longevity

[Guest guest]

Hi All,

See the not pdf-available below paper that may have us believe that the reduced

amount of fat tissue that we have could be the reason for the benefit to disease

avoidance. Knowledgeable CRers seem to hold contrary views.

Kloting N, Bluher M.

Extended longevity and insulin signaling in adipose tissue.

Exp Gerontol. 2005 Aug 24; [Epub ahead of print]

PMID: 16125891

Caloric restriction and leanness have been shown to increase longevity in

organisms

ranging from yeast to mammals. Adipose tissue seems to be a pivotal organ in the

aging process and in determination of lifespan. We have recently shown that

fat-specific disruption of the insulin receptor gene is sufficient to increase

lifespan in FIRKO mice, suggesting that reduced adiposity, even in the presence

of

normal or increased food intake, can extend lifespan. The model also suggests a

special role for the insulin-signaling pathway in adipose tissue in the

longevity

process. Reduced fat mass has an impact on the duration of life in several other

model organisms. In Drosophila, a specific reduction in the fat body through

overexpression of forkhead type transcription factor (dFOXO) extends lifespan.

Furthermore, sirtuin1 (SIRT1), the mammalian ortholog of the life-extending

yeast

gene silent information regulator 2 (SIR2), was proposed to be involved in the

molecular mechanisms linking lifespan to adipose tissue. In the control of human

aging and longevity, one of the striking physiological characteristics

identified in

centenarians is their greatly increased insulin sensitivity even compared with

younger individuals. The effect of reduced adipose tissue mass on lifespan could

be

due to the prevention of obesity-related metabolic disorders including type 2

diabetes and atherosclerosis.

Al Pater, PhD; email: old542000@...

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