tryptophan

What can high-tryptophan foods do for you?

• Help regulate your appetite
• Help you sleep better
• Elevate your mood

What events can indicate a need for more high-tryptophan foods?

• Depression
• Anxiety
• Irritability
• Impatience
• Impulsiveness
• Inability to concentrate
• Weight gain or unexplained weight loss
• Slow growth in children
• Overeating and/or carbohydrate cravings
• Poor dream recall
• Insomnia

Food sources of tryptophan include red meat, dairy products, nuts, seeds, bananas, soybeans and soy products, tuna, shellfish, and turkey.

For serving size for specific foods, see Nutrient Rating Chart below at the bottom of this page.

Description Function Deficiency Symptoms Toxicity Symptoms Cooking, storage and processing Factors that affect function

Drug-nutrient interaction Nutrient interaction Health conditions Supplements Food Sources Public Recommendations References

Description

What is tryptophan?

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.

How it Functions

What is the function of tryptophan?

Preventing Niacin Deficiency

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.

Raising Serotonin Levels

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.

Deficiency Symptoms

What are deficiency symptoms for tryptophan?

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.

Toxicity Symptoms

What are toxicity symptoms for tryptophan?

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 eosinophilia-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.

Impact of Cooking, Storage and Processing

How do cooking, storage or processing affect tryptophan?

There is no research showing problematic effects of cooking, storage, or processing on tryptophan levels in food.

Factors that Affect Function

What factors might contribute to a deficiency of tryptophan?

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.

Drug-Nutrient Interactions

What medications affect tryptophan?

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.

Nutrient Interactions

How do other nutrients interact with tryptophan?

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.

Health Conditions

What health conditions require special emphasis on tryptophan?

Tryptophan may play a role in the prevention and/or treatment of the following health conditions::

• Anxiety
• Depression
• Headaches
• Insomnia
• Nightmares
• Obesity
• Obsessive/compulsive disorder
• Pain
• Premenstrual syndrome
• Senile dementia
• Tourette's syndrome

Form in Dietary Supplements

What forms of tryptophan are found in dietary supplements?

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 fementation 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.

Food Sources

What foods provide 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.

 

Introduction to Nutrient Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the World's Healthiest Foods that are either an excellent, very good, or good source of tryptophan. Next to each food name, you'll find the serving size we used to calculate the food's nutrient composition, the calories contained in the serving, the amount of tryptophan contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

World's Healthiest Foods ranked as quality sources of: tryptophan
Food	Serving Size	Cals	Amount (g)	DV (%)	Nutrient Density	World's Healthiest Foods Rating
Shrimp, steamed/boiled	4 oz-wt	112.3	0.33	103.1	16.5	excellent
Tamari (Soy Sauce)	1 tbs	10.8	0.03	9.4	15.6	very good
Crimini mushrooms, raw	5 oz-wt	31.2	0.08	25.0	14.4	excellent
Cod, baked/broiled	4 oz-wt	119.1	0.29	90.6	13.7	excellent
Tuna, yellowfin, baked/broiled	4 oz-wt	157.6	0.38	118.8	13.6	excellent
Snapper, baked/broiled	4 oz-wt	145.2	0.33	103.1	12.8	excellent
Halibut, baked/broiled	4 oz-wt	158.8	0.34	106.3	12.0	excellent
Mustard greens, boiled	1 cup	21.0	0.04	12.5	10.7	excellent
Chicken breast, roasted	4 oz-wt	223.4	0.39	121.9	9.8	excellent
Scallops, baked/broiled	4 oz-wt	151.7	0.26	81.3	9.6	excellent
Spinach, boiled	1 cup	41.4	0.07	21.9	9.5	excellent
Turkey breast, roasted	4 oz-wt	214.3	0.35	109.4	9.2	excellent
Tofu, raw	4 oz-wt	86.2	0.14	43.8	9.1	excellent
Lamb loin, roasted	4 oz-wt	229.1	0.35	109.4	8.6	excellent
Beef tenderloin, lean, broiled	4 oz-wt	240.4	0.36	112.5	8.4	excellent
Calf's liver, braised	4 oz-wt	187.1	0.25	78.1	7.5	excellent
Sardines	3.25 oz can	191.4	0.25	78.1	7.3	excellent
Salmon, chinook, baked/broiled	4 oz-wt	261.9	0.33	103.1	7.1	excellent
Soybeans, cooked	1 cup	297.6	0.37	115.6	7.0	excellent
Kelp (sea vegetable)	0.25 cup	8.6	0.01	3.1	6.5	good
Asparagus, boiled	1 cup	43.2	0.05	15.6	6.5	very good
Broccoli, steamed	1 cup	43.7	0.05	15.6	6.4	very good
Mustard seeds	2 tsp	35.0	0.04	12.5	6.4	very good
Mozzarella cheese, part-skim, shredded	1 oz-wt	72.1	0.08	25.0	6.2	very good
Cauliflower, boiled	1 cup	28.5	0.03	9.4	5.9	very good
Turnip greens, cooked	1 cup	28.8	0.03	9.4	5.9	very good
Egg, whole, boiled	1 each	68.2	0.07	21.9	5.8	very good
Collard greens, boiled	1 cup	49.4	0.05	15.6	5.7	very good
Swiss chard, boiled	1 cup	35.0	0.03	9.4	4.8	very good
Cow's milk, 2%	1 cup	121.2	0.10	31.3	4.6	very good
Kale, boiled	1 cup	36.4	0.03	9.4	4.6	very good
Kidney beans, cooked	1 cup	224.8	0.18	56.3	4.5	very good
Black beans, cooked	1 cup	227.0	0.18	56.3	4.5	very good
Lima beans, cooked	1 cup	216.2	0.17	53.1	4.4	very good
Split peas, cooked	1 cup	231.3	0.18	56.3	4.4	very good
Cucumbers, slices, with peel	1 cup	13.5	0.01	3.1	4.2	good
Navy beans, cooked	1 cup	258.4	0.19	59.4	4.1	very good
Pinto beans, cooked	1 cup	234.3	0.17	53.1	4.1	very good
Miso	1 oz	70.8	0.05	15.6	4.0	very good
Lentils, cooked	1 cup	229.7	0.16	50.0	3.9	very good
Green beans, boiled	1 cup	43.8	0.03	9.4	3.9	very good
Brussel sprouts, boiled	1 cup	60.8	0.04	12.5	3.7	very good
Goat's milk	1 cup	167.9	0.11	34.4	3.7	very good
Romaine lettuce	2 cup	15.7	0.01	3.1	3.6	good
Wheat, bulgur, cooked	1 cup	151.1	0.09	28.1	3.4	very good
Apricots	1 each	16.8	0.01	3.1	3.3	good
Pumpkin seeds, raw	0.25 cup	186.7	0.11	34.4	3.3	good
Sesame seeds	0.25 cup	206.3	0.12	37.5	3.3	good
Oats, whole grain, cooked	1 cup	147.4	0.08	25.0	3.1	good
Celery, raw	1 cup	19.2	0.01	3.1	2.9	good
Garbanzo beans (chickpeas), cooked	1 cup	269.0	0.14	43.8	2.9	good
Buckwheat, cooked	1 cup	154.6	0.08	25.0	2.9	good
Onions, raw	1 cup	60.8	0.03	9.4	2.8	good
Sunflower seeds, raw	0.25 cup	205.2	0.10	31.3	2.7	good
Rye, whole grain, uncooked	0.33 cup	188.7	0.09	28.1	2.7	good
Garlic	1 oz-wt	42.2	0.02	6.3	2.7	good
Green peas, boiled	1 cup	134.4	0.06	18.8	2.5	good
Barley, cooked	1 cup	270.0	0.12	37.5	2.5	good
Peanuts, raw	0.25 cup	207.0	0.09	28.1	2.4	good
Bell peppers, red, raw, slices	1 cup	24.8	0.01	3.1	2.3	good
Beets, Boiled	1 cup	74.8	0.03	9.4	2.3	good
Yogurt, low-fat	1 cup	155.1	0.06	18.8	2.2	good
Quinoa, uncooked	0.25 cup	158.9	0.06	18.8	2.1	good
Winter squash, baked, cubes	1 cup	80.0	0.03	9.4	2.1	good
Eggplant, cooked, cubes	1 cup	27.7	0.01	3.1	2.0	good
Cashews, raw	0.25 cup	196.6	0.07	21.9	2.0	good
Millet, cooked	1 cup	285.6	0.10	31.3	2.0	good
Almonds, dry roasted	0.25 cup	206.0	0.07	21.9	1.9	good
Walnuts	0.25 cup	163.5	0.05	15.6	1.7	good
Cabbage, shredded, boiled	1 cup	33.0	0.01	3.1	1.7	good
Potato, baked, with skin	1 cup	133.0	0.04	12.5	1.7	good
Summer squash, cooked, slices	1 cup	36.0	0.01	3.1	1.6	good
Brown rice, cooked	1 cup	216.4	0.06	18.8	1.6	good
Tomato, ripe	1 cup	37.8	0.01	3.1	1.5	good

World's Healthiest Foods Rating	Rule
excellent	DV>=75%	OR	Density>=7.6	AND	DV>=10%
very good	DV>=50%	OR	Density>=3.4	AND	DV>=5%
good	DV>=25%	OR	Density>=1.5	AND	DV>=2.5%

Public Health Recommendations

What are current public health recommendations for tryptophan?

In its most recent 2005 public health recommendations for amino acids (published as the Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients), National Academies Press, 2005), the National Academy of Sciences (NAS) established a general principle for tryptophan intake. The NAS recommended that all individuals 1 year of age or greater consume 7 milligrams of tryptophan for every 1 gram of food protein. Here is how that recommendation would look for each age and gender group, assuming RDA-level protein intake for each group:

• Children 1-3 years: 91 mg of tryptophan
• Children 4-8 years: 133 mg of tryptophan
• Males 9-13 years: 238 mg of tryptophan
• Males 14-18 years: 364 mg of tryptophan
• Males 19 years and older: 392 mg of tryptophan
• Females 9-13 years: 238 mg of tryptophan
• Females 14 years and older: 322 mg of tryptophan
• Pregnant or lactating females: 497 mg of tryptophan

References

• Bell C, Abrams J, Nutt D. Tryptophan depletion and its implications for psychiatry. Br J Psychiatry 2001 May;178:399-405 2001. PMID:15990.
• Celenza JL. Metabolism of tyrosine and tryptophan--new genes for old pathways. Curr Opin Plant Biol 2001 Jun;4(3):234-40 2001. PMID:16010.
• Crean J, Richards JB, and de Wit H. Effect of tryptophan depletion on impulsive behavior in men with or without a family history of alcoholism. Behav Brain Res 2002 Nov 15;136(2):349-57 2002.
• Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995 1995.
• Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima Health, Rocklin, CA, 2000 2000.
• Mahan K, Escott-Stump S. Krause's Food, Nutrition, and Diet Therapy. WB Saunders Company; Philadelphia, 1996 1996.
• Martinez A, Knappskog PM, Haavik J. A structural approach into human tryptophan hydroxylase and its implications for the regulation of serotonin biosynthesis. Curr Med Chem 2001 Jul;8(9):1077-91 2001. PMID:15980.
• Moore P, Landolt HP, Seifritz E, et al. Clinical and physiological consequences of rapid tryptophan depletion. Neuropsychopharmacology 2000 Dec;23(6):601-22 2000. PMID:16020.
• Van der Does AJ. The effects of tryptophan depletion on mood and psychiatric symptoms. J Affect Disord 2001 May;64(2-3):107-19 2001. PMID:16000.
• Widner B, Wirleitner B, Baier-Bitterlich G, et al. Cellular immune activation, neopterin production, tryptophan degradation and the development of immunodeficiency. Arch Immunol Ther Exp (Warsz) 2000;48(4):251-8 2000. PMID:16030.

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