Written by Vitaminstuff :
Tryptophan is one of the 10 essential amino acids that the body uses to synthesize the proteins it needs. It’s well-known for its role in the production of nervous system messengers, especially those related to relaxation, restfulness, and sleep.
Tryptophan has two important functions. First, a small amount of the tryptophan we get in our diet (about 3%) is converted into niacin (vitamin B3) by the liver. This conversion can help prevent the symptoms associated with niacin deficiency when dietary intake of this vitamin is low.
Second, tryptophan serves as a precursor for serotonin, a neurotransmitter that helps the body regulate appetite, sleep patterns, and mood. Because of its ability to raise serotonin levels, tryptophan has been used therapeutically in the treatment of a variety of conditions, most notably insomnia, depression, and anxiety.
As an essential amino acid, dietary deficiency of tryptophan may cause the symptoms characteristic of protein deficiency, which include weight loss and impaired growth in infants and children.
When accompanied by dietary niacin deficiency, lack of tryptophan in the diet may also cause pellagra, the classic niacin deficiency disease that is characterized by the “4 Ds” – dermatitis, diarrhea, dementia, and death. This condition is very rare in the United States, however, and cannot occur simply because of a tryptophan deficiency.
Dietary deficiency of tryptophan may lead to low levels of serotonin. Low serotonin levels are associated with depression, anxiety, irritability, impatience, impulsiveness, inability to concentrate, weight gain, overeating, carbohydrate cravings, poor dream recall, and insomnia.
High dietary intake of tryptophan from food sources is not known to cause any symptoms of toxicity. In addition, tryptophan has been given therapeutically, as a prescription medicine or dietary supplement, in doses exceeding five grams per day with no report of adverse effects.
However, in 1989, the use of dietary supplements containing tryptophan was blamed for the development of a serious condition called eosiniphilia-myalgia syndrome (EMS), which caused severe muscle and joint pain, high fever, weakness, swelling of the arms and legs, and shortness of breath in more than a thousand people. In addition, more than 30 deaths were attributed to EMS caused by tryptophan supplements.
Many experts believe that the EMS was caused by a contaminant that was found in one batch of tryptophan sold by one manufacturer and occurred in only a small number of susceptible individuals. However, the United States Food and Drug Administration, the agency responsible for overseeing the dietary supplement industry, remained convinced that high doses of tryptophan were categorically unsafe. Since 1989, tryptophan has not been available as a dietary supplement in the United States.
To date, a Tolerable Upper Intake Level (TUL) for tryptophan has not yet been established by the Institute of Medicine at the National Academy of Sciences.
Vitamin B6 is necessary for the conversion of tryptophan to both niacin and serotonin. Consequently, a dietary deficiency of vitamin B6 may result in low serotonin levels and/or impaired conversion of tryptophan to niacin.
In addition, several dietary, lifestyle, and health factors reduce the conversion of tryptophan to serotonin, including cigarette smoking, high sugar intake, alcohol abuse, excessive consumption of protein, hypoglycemia and diabetes.
People taking the anti-depressant medications known as selective serotonin reuptake inhibitors (SSRIs) (including Prozac, Paxil, and Zoloft) should consult a physician before taking any other supplement or medication that also increases the amount of, or the effect of, serotonin, in the body.
Vitamin B6, vitamin C, folic acid and magnesium are necessary for the metabolization of tryptophan. In addition, tyrosine and phenylalanine compete with tryptophan for absorption.
Because of this, some healthcare practitioners believe that food sources of tryptophan do not cause a significant enough increase in blood levels of tryptophan to produce therapeutic results, and that tryptophan must, therefore, be taken as a supplement to increase its blood levels.
Until 1989, tryptophan supplementation was standard practice in many countries around the world – including the United States – to treat insomnia, depression, and anxiety.
In the summer and fall of 1989, hundreds of people taking tryptophan supplements in the U.S. began to report the development of serious side effects including muscle and joint pain, high fever, weakness, swelling of the arms and legs, and shortness of breath, a constellation of symptoms that later became known as eosiniphilia-myalgia syndrome (EMS).
Upon investigation, it was discovered that nearly all of the cases of EMS could be traced back to a contaminant found in one batch of tryptophan produced by a Japanese manufacturer called Showa Denko K.K.
While all manufacturers of supplemental tryptophan synthesized this amino acid through a fermentation process using bacteria, several months before the outbreak of EMS, Showa Denko K.K. had altered its process to make it more efficient and was apparently unaware that a toxic contaminant was being produced.
The United States Food and Drug Administration took immediate steps to limit the availability of tryptophan, and since 1989 this amino acid has not been sold as a dietary supplement. Tryptophan is still available, however, for use in the manufacture of infant formulas and entereral and parenteral (intravenous) nutritional supplements prescribed by physicians.
A few years ago, a new tryptophan-like supplement emerged in the U.S. marketplace. This supplement is called 5-hydroxytryptophan or 5-HTP. 5-HTP has been used in much the same way as tryptophan for the treatment of depression and insomnia, and for weight loss.
The reason is simple: the body ordinarily takes tryptophan and converts it into 5-HTP, and then takes the 5-HTP and converts it into serotonin. By taking 5-HTP, a person is taking a compound that is actually one step closer to serotonin than tryptophan.
Tryptophan occurs naturally in nearly all foods that contain protein, but in small amounts compared to the other essential amino acids. The following foods contain tryptophan: red meat, dairy products, nuts, seeds, bananas, soybeans and soy products, tuna, shellfish, and turkey.
The complete list with all amino acids ( with all links ) is on :