Posted by Larry Hoover on January 7, 2003, at 10:09:04
In reply to Re: Question for Larry Hoover » Larry Hoover, posted by johnj on January 6, 2003, at 9:58:55
> Hi Larry:
>
> Here is a more general question regarding amino acids and supplements. I hear that the amino acids have trouble crossing the blood brain barrier. I found a book about a 5 step natural approach to depression(can't remember the author) and he was in big favor of supplements and amiono acids. The ones he mentioned were GABA, DL-P(which we discussed), 5HTP, and tyrosine. Do you have any beliefs on using any of these?The blood-brain barrier (BBB) blocks many substances in the blood from accessing brain tissue. For things the brain needs, there are a variety of transporters to pump those things out of the blood. The amino acids that you mentioned, with the exception of GABA, are all transported by the "large neutral amino acid transporter", called LAT1. Which amino gets into the brain is dependent on what is in the blood rather than on what the brain needs. The aminos that bind to this transporter (valine, methionine, isoleucine, leucine, tyrosine, histidine, phenylalanine, and tryptophan), and derivatives like 5-HTP and melatonin, all compete for access to the same transporter system. There are differences in the ability to bind to the transporter, when comparing the aminos, but what gets taken up into the brain is largely concentration-dependent, i.e. the higher the concentration of one of these aminos in the blood (relative to the others), the more likely it is that that amino is going to land on the receptor before something else gets there and blocks its path. So, taking little bursts of pure amino acids is going to increase the odds that your brain is going to take up that particular amino acid.
GABA does not pass the blood-brain barrier, but it probably has peripheral effects (effects everywhere else other than the central nervous system).
5-HTP in particular may be a problematic supplement, but the adverse effects (if any) would be dose-dependent. 5-HTP is the intermediate between tryptophan and serotonin. The enzyme that creates it from tryptophan is under tight regulation, whereas the one that finishes the job is found throughout the body. The formation of 5-HTP is considered to be the "rate controlling step", as the second transformation occurs virtually instantaneously. Taking 5-HTP orally will increase the availability of serotonin throughout the body, not just in the brain. Some doctors are concerned about the possibility of too much serotonin floating around in the body, but just to emphasize, the dose is important. 50 mg a day is probably totally safe, but I couldn't say what the upper safe limit is.
>I would like to try some one by one. I often hear about melatonin, but also read that taking it too much can stop the bodies production of it. Does this seem possible? Thanks again and have a good day.
> johnjMelatonin supplements are probably perfectly safe, so long as you take as little as possible. Disturbances in melatonin secretion by the pineal gland are at least in part responsible for some of the symptoms of seasonal affective disorder, and for sleep disturbances related to other depressive syndromes.
Starting dose could be as little as 0.5 mg, taken 20 minutes to one hour before your intended bedtime. Go up by 0.5 mg at a time until you find the lowest effective dose. There is some evidence that taking melatonin supplements can help restore the pineal gland to normal cycles, rather than shutting it down.
poster:Larry Hoover
thread:134638
URL: http://www.dr-bob.org/babble/20030106/msgs/134807.html