tristan
Beiträge: 709 Registriert: November 2005
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hey,
zu methionin habe ich letztens was nicht so tolles gelesen. Habe mich nicht näher mit beschäftigt, aber vielleicht solltest du das machen wenn du das nehmen willst. Du könntest niedrigdosiert Kupfer nehmen.
MR = methionine restriction
"MR has repeatedly resulted in life span extension comparable to that seen
in energy restricted animals. In one of our typical studies using Fischer
344 rats, MR resulted in a 42% increase in mean survival and a 44% increase
in maximal longevity (Fig. 1). While living longer, animals on MR grow
significantly less (Fig. 2), and consume more food when food intake is
expressed on a per body mass basis. This latter observation has led to some
controversy, since when expressed on a per animal basis, MR rats, being
smaller, consume slightly less food per animal than their C-fed
counterparts. This has left open the possibility that the effect of
methionine restriction on life span is secondary to a restriction of caloric
intake, and not due to methionine deficiency. In order to examine the
proposition that MR might be an effect secondary to CR, we have pair-fed
rats, so that animals consumed control diet in the same quantity as consumed
by methionine restricted rats. Since animals fed in this way will consume
exactly the same energy levels regardless of which diet they consume, this
would exclude caloric intake as an explanation for the MR effect. When C
rats were fed in quantities equivalent to that consumed by MR animals they
consumed all of the food offered, and there was a modest reduction in weight
gain relative to ad libitum fed C animals. However, there was no
prolongation of life span (Fig. 3) associated with the slightly reduced food
intake and body size (Fig. 4), indicating that life span extension
associated with restricted methionine intake is not primarily due to reduced
energy consumption."
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The food you eat may change your genes for life
"iT SOUNDS like science fiction: simply swallowing a pill, or eating a specific food supplement, could permanently change your behaviour for the better, or reverse diseases such as schizophrenia, Huntington's or cancer.
Yet such treatments are looking increasingly plausible. In the latest development, normal rats have been made to behave differently just by injecting them with a specific amino acid. The change to their behaviour was permanent. The amino acid altered the way the rat's genes were expressed, raising the idea that drugs or dietary supplements might permanently halt the genetic effects that predispose people to mental or physical illness.
It is not yet clear whether such interventions could work in humans. But there is good reason to believe they could, as evidence mounts that a range of simple nutrients might have such effects.
Two years ago, researchers led by Randy Jirtle of Duke University Medical Center in Durham, North Carolina, showed that the activity of a mouse's genes can be influenced by food supplements eaten by its mother just prior to, or during, very early pregnancy (New Scientist, 9 August 2003, p 14). Then last year, Moshe Szyf, Michael Meaney and colleagues at McGill University in Montreal, Canada, showed that mothers could influence the way a rat's genes are expressed after it has been born. If a rat is not licked, groomed and nursed enough by its mother, chemical tags known as methyl groups are added to the DNA of a particular gene.
The affected gene codes for the glucocorticoid receptor gene, expressed in the hippocampus of the brain. The gene helps mediate the animal's response to stress, and in poorly raised rats, the methylation damped down the gene's activity. Such pups produced higher levels of stress hormones and were less confident exploring new environments. The effect lasted for life (Nature Neuroscience, vol 7, p 847).
Now the team has shown that a food supplement can have the same effect on well-reared rats at 90 days old - well into adulthood. The researchers injected L-methionine, a common amino acid and food supplement, into the brains of well-reared rats. The amino acid methylated the glucocorticoid gene, and the animals' behaviour changed. "They were almost exactly like the poorly raised group," says Szyf, who announced his findings at a small meeting on environmental epigenomics earlier this month in Durham, North Carolina.
Though the experiment impaired well-adjusted animals, the opposite should be possible, and Szyf has already shown that a chemical called TSA that is designed to strip away methyl groups can turn a badly raised rat into a more normal one.
No one is envisaging injecting supplements into people's brains, but Szyf says his study shows how important subtle nutrients and supplements can be. "Food has a dramatic effect," he says. "But it can go both ways," he cautions. Methionine, for instance, the supplement he used to make healthy rats stressed, is widely available in capsule form online or in health-food stores - and the molecules are small enough to get into the brain via the bloodstream.
Rob Waterland from Baylor College of Medicine in Houston, Texas, who attended the meeting, says Szyf's ideas are creating a buzz, as they suggest that methylation can influence our DNA well into adulthood. A huge number of diseases are caused by changes to how our DNA is expressed, and this opens up new ways of thinking about how to prevent and treat them, he says.
But Waterland points out there is still much work to be done. Substances like methionine and TSA are, he says, a "sledgehammer approach", in that they are likely to demethylate lots of genes, and we don't even know which they will affect. But he speculates that techniques such as "RNA-directed DNA methylation", so far tested only in plants but theoretically possible in mammals, may allow us to target such methylation much more precisely.
From issue 2526 NSM
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