Re: Leucine

[Guest guest]

I just got my first review on leucine into the journal

of nutrition. Here is the link for you all.

http://www.nutrition.org/cgi/content/abstract/136/2/533S

-Layne Norton

university of Illinois

Food Science and Human Nutrition

Champaign, IL USA

--- carruthersjam wrote:

> Members may be interested in the following:

>

> The secret of 'muscular' old age

>

> http://news.bbc.co.uk/1/hi/health/4502862.stm

>

> <<<Scientists believe they have found a way to

> enable the elderly to

> maintain muscle. Muscle is constantly being built

> and broken down,

> which works to maintain a balance in young adults.

> But as people age,

> the breakdown process is more successful than the

> muscle-building

> action. However French researchers, writing in the

> Journal of

> Physiology, say adding the amino acid leucine to old

> people's diets

> could help them keep muscle.

>

> Leucine is found in meat soy, beans and legumes,

> among other foods.

> Slow down Once adults reach 40, they start to lose

> between 0.5 and 2%

> of their muscle each year. The team from the Human

> Nutrition Research

> Centre of Auvergne, in Clermont-Ferrand, France

> looked at the

> behaviour of proteins in muscle.

>

> As in all mammalian tissues, proteins are created

> (synthesised) from

> amino acids and digested (degraded) by enzymes.

> Straight after a

> meal, the rate of synthesis doubles, prompted by the

> arrival of a

> large amount of amino acids. The rate of the

> breakdown of protein is

> highest in-between meals.

>

> The difference between the two rates determines how

> much protein

> remains in the muscle. But, in older animals - and,

> it is believed,

> humans - the amino acid stimulus prompting synthesis

> is less

> effective, and the process slows down. However, the

> breakdown of

> proteins is not, leaving older animals with less

> protein than their

> younger counterparts.

>

> The researchers compared protein breakdown in young

> (eight-month-old)

> and old (22-month) rats. They discovered that the

> slow down in

> degradation that normally follows a meal does not

> occur in old

> animals, so there is excessive breakdown. But when

> the scientists

> boosted levels of one amino acid, leucine, the

> balance of synthesis

> and breakdown was restored.

>

> Falls danger The team, led by Dr Didier Attaix,

> suggest the protein

> processing imbalance which comes with age results

> from defects in the

> complex machinery that breaks down muscle protein,

> and that leucine

> supplementation can fully restore correct function.

> He

> said: " Preventing muscle wasting is a major

> socio-economic and public

> health issue, that we may be able to combat with a

> leucine-rich

> diet. "

>

> Dr Rennie from the University of Nottingham

> Medical School at

> Derby told the BBC News website more research into

> the finding was

> needed. But he said older people could make changes

> to their diet now

> which could help them maintain muscle. " If they

> don't, they can fall

> over more easily; they can trip down stairs or fall

> in the bath. " Dr

> Rennie said older people could act now, even before

> further research

> had been carried out. " Leucine is most abundant in

> meat, so it makes

> sense in terms of protein synthesis to eat meat. " As

> people get

> older, they tend to need to eat less. But people

> should maintain

> their protein intake as they age. " >>>>

>

> -------------

> Carruthers

> Wakefield, UK