X-Message-Number: 28262
Date: Tue, 25 Jul 2006 19:31:56 -0700 (PDT)
From: Doug Skrecky <>
Subject: meeting one RDA may accelerate aging

[BTW: There is no proof yet that methionine restriction can slow human
aging.]

Aging Cell. 2005 Jun;4(3):119-25.
Methionine-deficient diet extends mouse lifespan, slows immune and lens
aging, alters glucose, T4, IGF-I and insulin levels, and increases
hepatocyte MIF levels and stress resistance.
  A diet deficient in the amino acid methionine has previously been shown
to extend lifespan in several stocks of inbred rats. We report here that
a methionine-deficient (Meth-R) diet also increases maximal lifespan in
(BALB/cJ x C57BL/6 J)F1 mice. Compared with controls, Meth-R mice have
significantly lower levels of serum IGF-I, insulin, glucose and thyroid
hormone. Meth-R mice also have higher levels of liver mRNA for MIF
(macrophage migration inhibition factor), known to be higher in several
other mouse models of extended longevity. Meth-R mice are significantly
slower to develop lens turbidity and to show age-related changes in T-cell
subsets. They are also dramatically more resistant to oxidative liver
cell injury induced by injection of toxic doses of acetaminophen. The
spectrum of terminal illnesses in the Meth-R group is similar to that
seen in control mice. Studies of the cellular and molecular biology of
methionine-deprived mice may, in parallel to studies of
calorie-restricted mice, provide insights into the way in which
nutritional factors modulate longevity and late-life illnesses.

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