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L-Tryptophan is an essential amino acid. It is converted by the body into nicotinic acid and to serotonin.
Uses for tryptophan which have been documented include:
I. Influencing the diet. |
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A. Tryptophan levels in the brain depend on 2 factors |
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1. Total serum tryptophan levels
2. Ratio between serum tryptophan and 5 other amino acids; tyrosine, phenylalanine, leucine, isoleucine, and valine. These are all large, neutral amino acids, and compete with tryptophan for crossing the blood-brain barrier. High protein meals provide serum levels of all these amino acids, so less net amount of tryptophan is able to cross into the brain. So, if low protein, high carbohydrate meal is eaten, and at the same time, a tryptophan supplement is taken, much higher amounts of tryptophan are able to cross the blood-brain barrier. (Because these other amino acids are circulating as free molecules, the carbohydrate meal increases insulin, and forces most serum levels into cells.But tryptophan remains unaffected by insulin, so more crosses the blood-brain barrier).People who wish to control their diet and have carbohydrate cravings can use this effect to decrease cravings, since tryptophan produces serotonin, which reduces carbohydrate cravings. In practical terms, a small carbohydrate serving prior to a meal reduces overall carbohydrate intake, and supplementing this with tryptophan should reduce this even further. Conversely, high protein meals actually result in lower brain levels of tryptophan. |
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II. Depression and Sleeplessness. |
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A. There is an Inverse relationship between tryptophan consumption and emotional complaints. |
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1. Serotonin is directly involved in mood, and amount of serotonin is limited by availability of tryptophan. The class of antidepressants known as SSRI's increase by inhibiting cellular reuptake, not by increasing available serotonin. This class of drugs includes the most widely prescribed drugs for depression, namely Prozac, Paxil, and Zoloft.
2. Tryptophan has been widely reported to be effective in sleeplessness. Lack of serotonin is reported to be the major factor in sleeplessness. Current sleeping pills basically shut down the brain, interfering with the brain's ability to process the day's information. We know this processing as "dreaming" Many people who take these sleeping pills report that although they slept, they do not awaken feeling refreshed.This is attributed to the disruption in dreaming these drugs produce. Tryptophan, on the other hand, increases the level of serotonin, which has been shown to dramatically decrease sleep latency, (the time it takes to fall asleep), and does not interfere with dreaming. This allows a more natural sleep, without affecting the various stages of sleep. Vitamin B-6 and magnesium enhance this effect.
3. Endogenous depression (which means that there is no outwardly visible reason for the depression) has been treated with tryptophan with more mixed results. It appears that the antidepressant effect occurs at higher dosages (3 to 5 grams per day) and may take quite a long time to work. At a dose of 6 grams per day, the result has been associated with lessened effect, possibly because of induction of liver enzymes. Also, it is important to avoid high protein meals at the time tryptophan is taken because of the above-mentioned competitive inhibition with the other amino acids.
4. Various types of chronic pain (eg. arthritis, migraine headache, other chronic headaches, and other types of chronic pain may also be alleviated by tryptophan. This is not a well-documented result, but it is theorized that chronic pain is caused in part by a relative lack of serotonin in the brain. In addition, narcotic pain medications work through serotonin levels also, and if these levels are down, the narcotics are not as effective. |
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III. Adverse effects
Animal studies in pregnancy have hinted at possible problems (reduced litter size and increased mortalityin hamsters.) No such effect has been documented in humans. Old claims of possible bladder cancer have never been substantiated. High doses (4-5gm/day) have been shown to produce fatty deposits in liver in animal studies. No human effect has been found. Toxicity reported in contaminated otc products from December, 1989
If you or your doctor have any specific questions, please feel free to use our
"Ask the Pharmacist" option for a response via email.
Bibliography:
Amino Acids in Therapy 1985
Leon Chaitow
Pain-Free Tryptophan Diet 1986
Robert Pollack, PhD.
The Doctor's Vitamin and Mineral Encyclopedia, 1990 Sheldon Saul Hendler, M.D.
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