Protein Restriction ........... Was: Leucine vs CR Catabolism

[Guest guest]

Hi folks:

More on protein restriction:

" Mitochondrial oxidative stress, aging and caloric restriction: The

protein and methionine connection.

Pamplona R, Barja G.

Department of Basic Medical Sciences, University of Lleida, Lleida

25008, Spain.

Caloric restriction (CR) decreases aging rate and mitochondrial ROS

(MitROS) production and oxidative stress in rat postmitotic tissues.

Low levels of these parameters are also typical traits of long-lived

mammals and birds. However, it is not known what dietary components

are responsible for these changes during CR. It was recently observed

that 40% protein restriction without strong CR also decreases MitROS

generation and oxidative stress. This is interesting because protein

restriction also increases maximum longevity (although to a lower

extent than CR) and is a much more practicable intervention for

humans than CR. Moreover, it was recently found that 80% methionine

restriction substituting it for l-glutamate in the diet also

decreases MitROS generation in rat liver. Thus, methionine

restriction seems to be responsible for the decrease in ROS

production observed in caloric restriction. This is interesting

because it is known that exactly that procedure of methionine

restriction also increases maximum longevity. Moreover, recent data

show that methionine levels in tissue proteins negatively correlate

with maximum longevity in mammals and birds. All these suggest that

lowering of methionine levels is involved in the control of

mitochondrial oxidative stress and vertebrate longevity by at least

two different mechanisms: decreasing the sensitivity of proteins to

oxidative damage, and lowering of the rate of ROS generation at

mitochondria. "

PMID: 16574059

Rodney.

>

> >

> > Hi Dave:

> >

> > I remember one study posted here about a year ago which quite

> > strongly suggested tryptophan (I believe it was tryptophan)

should

> > be minimized. But upon investigation it was noted that pretty

much

> > everything contains it so there wasn't an easy way to minimize it

> > apart from reducing overall protein intake.

>