Posted by KaraS on August 11, 2004, at 22:21:37
In reply to Re: Supplements for brain fog? Phenylalanine » KaraS, posted by robot on August 11, 2004, at 21:08:12
> Thanks Kara. I just found this study, and here is the first paragraph of the Discussion section:
>
> "Although no effect of tyrosine supplementation on neuropsychological test performance was found, the findings provide further evidence for a long term biochemical basis for the neuropsychological deficits associated with early treated phenylketonuria. Significant correlations between concurrent phenylalanine levels and task performance were obtained for several of the neuropsychological measures. Higher phenylalanine levels were associated with poorer performance on tests of verbal memory, response organisation, and reaction time under conditions of sustained vigilance. These results add to the solid body of findings indicating the neurotoxic effects of phenylalanine."
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> There are footnotes for that paragraph too. Here's the website:
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> http://adc.bmjjournals.com/cgi/content/full/archdischild;78/2/116
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> Ive seen that word "neurotoxic" associated with it more than once.
>
> Here's another part:
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> "What is not known in the present study or other recent investigations is the effect of dietary supplementation on brain levels of tyrosine. Of more importance than the plasma tyrosine level itself is the ratio of phenylalanine to tyrosine, since phenylalanine competes with tyrosine for carrier proteins at the blood-brain barrier. Although the dietary supplements increased the amount of tyrosine in plasma, they did not significantly alter the phenylalanine to tyrosine ratio, which was approximately 18:1 when subjects were ingesting tyrosine and 20:1 when they were not. Both of these ratios were well above the normal 1:1 ratio. "
>
> Anyway, my idea was this: to try taking the spirulina again (it has great health benefits and lots of protein, cleanses digestive system) but taking it with Tyrosine supplements. Since Tyrosine and Phenylalanine compete with each other at the bloodbrainbarrier, this should limit the amount of phenyl Im getting in my brain. At least Ill try, and if the mental deficits happen again I might just have to give up trying.
> I do have some L-phenylalanine (500 mg capsules)--I might try to take those again and see if they have the same effect.
> It does sem odd that if it can have negative effects on mental tasks why it would be used to treat ADD sufferers.
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> thanks again
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>Hi Robot,
I won't have a chance for a couple of days to really read this and investigate but my initial response to your first quoted paragraph was that it was talking about people who have the condition phenylketonuria. They can't process phenylalanine correctly so phenylalanine is toxic for them. But again, I'll have to read all of this over when I have more time and can give you a better answer.Take care.
Kara
poster:KaraS
thread:359642
URL: http://www.dr-bob.org/babble/alter/20040718/msgs/376666.html