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L-tryptophan is an amino acid, a protein building block that can be found in many plant and animal proteins. L-tryptophan is called an “essential†amino acid because the body can’t make it. It must be acquired from food. L-tryptophan is used for insomnia, sleep apnea, depression, anxiety, facial pain, a severe form of premenstrual syndrome called premenstrual dysphoric disorder (PMDD), smoking cessation, grinding teeth during sleep (bruxism), attention deficit-hyperactivity disorder (ADHD), Tourette's syndrome, and to improve athletic performance.
L-tryptophan is naturally found in animal and plant proteins. L-tryptophan is considered an essential amino acid because our bodies can't make it. It is important for the development and functioning of many organs in the body. After absorbing L-tryptophan from food, our bodies convert it to 5-HTP (5-hyrdoxytryptophan), and then to serotonin. Serotonin is a hormone that transmits signals between nerve cells. It also causes blood vessels to narrow. Changes in the level of serotonin in the brain can alter mood.
What is L-tryptophan?
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Tryptophan or (2S)-2-amino-3-(1H-indol-3-yl)propanoic acid
Other names
2-Amino-3-(1H-indol-3-yl)propanoic acid |
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L-Tryptophan is a natural anti-depressant, plentiful in protein foods but largely lost through cooking and processing. L-Tryptophan is a naturally occurring amino-acid. It is a precursor for the mood-regulating serotonin the brain neurotransmitter linked with pleasure and fulfillment. L-Tryptophan's is used to alleviate depression, support alcohol withdrawal and to aid weight loss. It plays an important role in our diets, and aging individuals are often in need of it as a supplement.
How is it Made?
Plants and microorganisms commonly synthesize tryptophan from shikimic acid or anthranilate. The latter condenses with phosphoribosylpyrophosphate (PRPP), generating pyrophosphate as a by-product. After ring opening of the ribose moiety and following reductive decarboxylation, indole-3-glycerinephosphate is produced, which in turn is transformed into indole. In the last step, tryptophan synthase catalyzes the formation of tryptophan from indole and the amino acid serine.
Where is it Found?
Tryptophan is a routine constituent of most protein-based foods or dietary proteins. It is particularly plentiful in chocolate, oats, dried dates, milk, yogurt, cottage cheese, red meat, eggs, fish, poultry, sesame, chickpeas, sunflower seeds, pumpkin seeds, spirulina, and peanuts. Despite popular belief that turkey has a particularly high amount of tryptophan, the amount of tryptophan in turkey is typical of most poultry.
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Food |
Protein
[g/100 g of food] |
Tryptophan
[g/100 g of food] |
Tryptophan/Protein [%] |
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egg, white, dried |
81.10 |
1.00 |
1.23 |
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spirulina, dried |
57.47 |
0.93 |
1.62 |
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cod, atlantic, dried |
62.82 |
0.70 |
1.11 |
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soybeans, raw |
36.49 |
0.59 |
1.62 |
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pumpkin seed |
33.08 |
0.57 |
1.72 |
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cheese, Parmesan |
37.90 |
0.56 |
1.47 |
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caribou |
29.77 |
0.46 |
1.55 |
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sesame seed |
17.00 |
0.37 |
2.17 |
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cheese, cheddar |
24.90 |
0.32 |
1.29 |
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sunflower seed |
17.20 |
0.30 |
1.74 |
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pork, chop |
19.27 |
0.25 |
1.27 |
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turkey |
21.89 |
0.24 |
1.11 |
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chicken |
20.85 |
0.24 |
1.14 |
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beef |
20.13 |
0.23 |
1.12 |
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salmon |
19.84 |
0.22 |
1.12 |
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lamb, chop |
18.33 |
0.21 |
1.17 |
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perch, Atlantic |
18.62 |
0.21 |
1.12 |
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egg |
12.58 |
0.17 |
1.33 |
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wheat flour, white |
10.33 |
0.13 |
1.23 |
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baking chocolate, unsweetened |
12.9 |
0.13 |
1.23 |
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milk |
3.22 |
0.08 |
2.34 |
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rice, white |
7.13 |
0.08 |
1.16 |
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oatmeal, cooked |
2.54 |
0.04 |
1.16 |
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potatoes, russet |
2.14 |
0.02 |
0.84 |
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banana |
1.03 |
0.01 |
0.87 | |
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Benefits / Uses
L-tryptophan (sometimes known as tryptophan) is an amino acid. It is essential for human nutrition, as the human body cannot produce L-tryptophan on its own. L-tryptophan supplements are sometimes claimed to be beneficial for treating the following conditions:
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Depression |
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Anxiety |
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Insomnia |
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Premenstrual syndrome (PMS) |
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Premenstrual dysphoric disorder (PMDD) |
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Attention deficit hyperactivity disorder (ADHD) |
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Teeth grinding (bruxism) |
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Tourette syndrome. | |
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L-tryptophan is also sometimes used to help people quit smoking and to enhance athletic performance.
Dosage
There are a wide range of doses, from a general supplement at 500 mg to 1000 mg daily, to treatment of severe depression and senile dementia at 2000 mg to 3000 mg daily.
Possible Side-Effects / Precautions / Possible Interactions
L-tryptophan is possibly unsafe when taken by mouth. It has been linked to over 1500 reports of eosinophilia-myalgia syndrome (EMS) and 37 deaths. EMS is a neurological condition with symptoms that include fatigue; intense muscle pain; nerve pain; skin changes; baldness; rash; and pain and swelling affecting the joints, connective tissue, lungs, heart, and liver. Symptoms tend to improve over time, but some people may still experience symptoms up to 2 years after they develop EMS. Some people report that their symptoms have never gone away completely.
In 1990, L-tryptophan was recalled from the market due to these safety concerns. After the limitation of L-tryptophan products, the number of EMS cases dropped sharply. The exact cause of EMS in patients taking L-tryptophan is unknown, but some evidence suggests it may be due to contaminated L-tryptophan products. About 95% of all EMS cases were traced to L-tryptophan produced by a single manufacturer in Japan. Currently, under the Dietary Supplement Health and Education Act (DHSEA) of 1994, L-tryptophan is available and marketed as a dietary supplement.
L-tryptophan can cause some side effects such as heartburn, stomach pain, belching and gas, nausea, vomiting, diarrhea, and loss of appetite. It can also cause headache, lightheadedness, drowsiness, dry mouth, visual blurring, muscle weakness, and sexual problems.
Special Precautions & Warnings:
Pregnancy and breast-feeding: L-tryptophan is likely unsafe in pregnancy because it may harm the unborn child. Not enough is known about the safety of L-tryptophan during breast-feeding. Avoid using L-tryptophan during pregnancy and breast-feeding.
A white blood cell disorder called eosinophilia: L-tryptophan might make this condition worse. L-tryptophan has been associated with the development of eosinophilia-myalgia syndrome (EMS).
Liver or kidney disease: L-tryptophan might make these conditions worse since it has been associated with the development of eosinophilia-myalgia syndrome (EMS).
Possible Interaction:
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Medications for depression (Antidepressant drugs) interacts with L-TRYPTOPHAN |
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L-tryptophan increases a brain chemical called serotonin. Some medications for depression also increase the brain chemical serotonin. Taking L-tryptophan along with these medications for depression might increase serotonin too much and cause serious side effects including heart problems, shivering, and anxiety. Do not take L-tryptophan if you are taking medications for depression.
Some of these medications for depression include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and others. |
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Medications for depression (MAOIs) interacts with L-TRYPTOPHAN |
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L-tryptophan increases a chemical in the brain. This chemical is called serotonin. Some medications used for depression also increase serotonin. Taking L-tryptophan with these medications used for depression might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, and anxiety.
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others. |
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Sedative medications (CNS depressants) interacts with L-TRYPTOPHAN |
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L-tryptophan might cause sleepiness and drowsiness. Medications that cause sleepiness are called sedatives. Taking L-tryptophan along with sedative medications might cause too much sleepiness. | |
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Some sedative medications include clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and others.
Research Studies / References
References
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Riemann, D., et al., The tryptophan depletion test: impact on sleep in primary insomnia - a pilot study. Psychiatry Res, 2002. 109(2): p. 129-35. |
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Levitan, R.D., et al., Preliminary randomized double-blind placebo-controlled trial of tryptophan combined with fluoxetine to treat major depressive disorder: antidepressant and hypnotic effects. J Psychiatry Neurosci, 2000. 25(4): p. 337-46. |
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Demisch, K., J. Bauer, and K. Georgi, Treatment of severe chronic insomnia with L-tryptophan and varying sleeping times. Pharmacopsychiatry, 1987. 20(6): p. 245-8. |
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Spinweber, C.L., L-tryptophan administered to chronic sleep-onset insomniacs: late- appearing reduction of sleep latency. Psychopharmacology, 1986. 90(2): p. 151-5. |
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Fitten, L.J., J. Profita, and T.G. Bidder, L-tryptophan as a hypnotic in special patients. J Am Geriatr Soc, 1985. 33(4): p. 294-7. |
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Hartmann, E., J.G. Lindsley, and C. Spinweber, Chronic insomnia: effects of tryptophan, flurazepam, secobarbital, and placebo. Psychopharmacology, 1983. 80(2): p. 138-42. |
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Schneider-Helmert, D., Interval therapy with L-tryptophan in severe chronic insomniacs. A predictive laboratory study. Int Pharmacopsychiatry, 1981. 16(3): p. 162-73. |
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Hartmann, E. and R. Elion, The insomnia of 'sleeping in a strange place': effects of l-tryptophane. Psychopharmacology (Berl), 1977. 53(2): p. 131-3. |
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Schneider-Helmert, D. and C.L. Spinweber, Evaluation of L-tryptophan for treatment of insomnia: a review. Psychopharmacology, 1986. 89(1): p. 1-7. |
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Ferrero, F. and J. Zahnd, [Tryptophan in the treatment of insomnia in hospitalized psychiatric patients]. Encephale, 1987. 13(1): p. 35-7. |
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Dawson RMC, et al. (1969). Data for Biochemical Research. Oxford: Clarendon Press. ISBN 0-19-855338-2. |
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IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides". Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. http://www.chem.qmul.ac.uk/iupac/AminoAcid/. Retrieved 2007-05-17. |
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"Dr. Margaret Oakley Dayhoff". The Chemistry of Amino Acids. University of Arizona. http://www.biology.arizona.edu/biochemistry/problem_sets/aa/Dayhoff.html. Retrieved 7 September 2010. |
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Pallaghy PK, Melnikova AP, Jimenez EC, Olivera BM, Norton RS (1999). "Solution structure of contryphan-R, a naturally-occurring disulfide-bridged octapeptide containing D-tryptophan: comparison with protein loops". Biochemistry 38 (35): 11553–9. doi:10.1021/bi990685j. |
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Hopkienns FG, Cole SW (1901). "A contribution to the chemistry of proteids: Part I. A preliminary study of a hitherto undescribed product of tryptic digestion". J. Physiol. (Lond.) 27 (4-5): 418–28. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1540554. |
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Cox GJ, King H (1943), "L-Tryptophane", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV2P0612; Coll. Vol. 2: 612–616 |
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Radwanski ER, Last RL (1995). "Tryptophan biosynthesis and metabolism: biochemical and molecular genetics". Plant Cell 7 (7): 921–34. doi:10.1105/tpc.7.7.921. |
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Ikeda M (2002). "Amino acid production processes". Adv. Biochem. Eng. Biotechnol. 79: 1–35. http://www.springerlink.com/content/226q8plt36351kck. |
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Fernstrom JD (1983). "Role of precursor availability in control of monoamine biosynthesis in brain". Physiol. Rev. 63 (2): 484–546. http://physrev.physiology.org/cgi/reprint/63/2/484. |
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Schaechter JD, Wurtman RJ (1990). "Serotonin release varies with brain tryptophan levels". Brain Res. 532 (1-2): 203–10. doi:10.1016/0006-8993(90)91761-5. http://wurtmanlab.mit.edu/publications/pdf/790.pdf. | |
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