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.

 

Description

What is tryptophan?

Tryptophan is one of the 10 essential amino acids that the body uses to synthesize the proteins it needs. Many of us may be familiar with tryptophan as the purported cause of the post-Thanksgiving Dinner nap.

While the sleepy feeling that follows Thanksgiving dinner probably has multiple causes, turkey does contain a significant amount of tryptophan, and tryptophan is believed, under certain circumstances, to produce a sense of relaxation and/or drowsiness.

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

Introduction to Nutrient Rating System Chart

The following chart shows the foods which are either excellent, very good or good sources of this nutrient. Next to each food name you will find the following information: the serving size of the food; the number of calories in one serving; DV% (percent daily value) of the nutrient contained in one serving (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. For more detailed information on our Nutrient Rating System, please click here.

 

Foods Ranked as quality sources of:
tryptophan
Food Serving
Size
Cals Amount
(g)
DV
(%)
Nutrient
Density
World's
Healthiest
Foods Rating
Shrimp, MixedSpecies, 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
Mushrooms, Crimini, Raw 5 oz-wt 31.2 0.08 25.0 14.4 excellent
Cod, Pacific, Fillet, 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 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
Greens, Mustard, 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, with salt) 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
Liver, Calf 4 oz-wt 187.1 0.25 78.1 7.5 excellent
Chinook Salmon Fillet-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
Asparagus, Boiled 1 cup 43.2 0.05 15.6 6.5 very good
Broccoli (pieces, steamed) 1 cup 43.7 0.05 15.6 6.4 very good
Seeds, Mustard 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, drained) 1 cup 28.5 0.03 9.4 5.9 very good
Greens, Turnip, Cooked 1 cup 28.8 0.03 9.4 5.9 very good
Egg, Hen, Whole, Boiled 1 each 68.2 0.07 21.9 5.8 very good
Collard Greens, Boiled, Drained 1 cup 49.4 0.05 15.6 5.7 very good
Peppermint Leaves, Fresh 1 oz-wt 19.9 0.02 6.3 5.7 very good
Parsley, Fresh 1 oz-wt 10.2 0.01 3.1 5.5 good
Chard, Boiled 1 cup 35.0 0.03 9.4 4.8 very good
Milk, Cow, 2% 1 cup 121.2 0.10 31.3 4.6 very good
Kale, Fresh, Boiled 1 cup 36.4 0.03 9.4 4.6 very good
Beans, Kidney, Cooked 1 cup 224.8 0.18 56.3 4.5 very good
Beans, Black, Boiled 1 cup 227.0 0.18 56.3 4.5 very good
Beans, Lima, Cooked 1 cup 216.2 0.17 53.1 4.4 very good
Split Peas, Boiled 1 cup 231.3 0.18 56.3 4.4 very good
Cucumber, Raw 1 cup 13.5 0.01 3.1 4.2 good
Beans, Navy, Cooked 1 cup 258.4 0.19 59.4 4.1 very good
Beans, Pinto, Cooked 1 cup 234.3 0.17 53.1 4.1 very good
Miso (Soybean) 1 oz 70.8 0.05 15.6 4.0 very good
Lentils, Boiled 1 cup 229.7 0.16 50.0 3.9 very good
Green Snap/String Beans, Boiled 1 cup 43.8 0.03 9.4 3.9 very good
Brussels Sprouts, Boiled 1 cup 60.8 0.04 12.5 3.7 very good
Milk, Goat 1 cup 167.9 0.11 34.4 3.7 very good
Lettuce, Romaine 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, Raw 1 each 16.8 0.01 3.1 3.3 good
Pumpkin Seeds, Dried 0.25 cup 186.7 0.11 34.4 3.3 good
Seeds, Sesame 0.25 cup 206.3 0.12 37.5 3.3 good
Oats, Whole Grain 1 cup 145.1 0.08 25.0 3.1 good
Almonds 0.25 cup 205.2 0.11 34.4 3.0 good
Spelt WholeGrain Flour 2 oz-wt 189.0 0.10 31.3 3.0 good
Celery, Raw 1 cup 19.2 0.01 3.1 2.9 good
Beans, Garbanzo, Cooked 1 cup 269.0 0.14 43.8 2.9 good
Buckwheat Groats, 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, Dried 0.25 cup 205.2 0.10 31.3 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 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
Red Bell Peppers (sliced, raw) 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, Cow Milk, Low Fat 1 cup 155.1 0.06 18.8 2.2 good
Quinoa, Dry 0.25 cup 158.9 0.06 18.8 2.1 good
Squash, Winter, All Varieties 1 cup 80.0 0.03 9.4 2.1 good
Eggplant, Boiled 1 cup 27.7 0.01 3.1 2.0 good
Nuts, 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
Nuts, 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
Squash, Summer, All Varieties 1 cup 36.0 0.01 3.1 1.6 good
Rice, Long Grain Brown, Cooked 1 cup 216.4 0.06 18.8 1.6 good
Rye Cereal, Cream of, Cooked 1 cup 108.6 0.03 9.4 1.6 good
Tomato, Red, Raw, 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?

To date, the Institute of Medicine has not established Dietary Reference Intakes for tryptophan. However, various organizations, including the World Health Organization, have estimated the amount of tryptophan necessary to maintain health. The estimated daily tryptophan requirements appear below:

  • Infants up to two years: 17 mg/kg
  • Children 2-10 years: 12.5 mg/kg
  • Males and females 10-18 years: 3.3 mg/kg
  • Adults: 3.5 mg/kg

References

  • Bell C, Abrams J, Nutt D. Tryptophan depletion and its implications for psychiatry. Br J Psychiatry 2001 May;178:399-405.
  • Celenza JL. Metabolism of tyrosine and tryptophan--new genes for old pathways. Curr Opin Plant Biol 2001 Jun;4(3):234-40.
  • 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.
  • Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995.
  • Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima Health, Rocklin, CA, 2000.
  • Mahan K, Escott-Stump S. Krause's Food, Nutrition, and Diet Therapy. WB Saunders Company; Philadelphia, 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.
  • Moore P, Landolt HP, Seifritz E, et al. Clinical and physiological consequences of rapid tryptophan depletion. Neuropsychopharmacology 2000 Dec;23(6):601-22.
  • Van der Does AJ. The effects of tryptophan depletion on mood and psychiatric symptoms. J Affect Disord 2001 May;64(2-3):107-19.
  • 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.

This page was updated on: 2003-12-11 20:14:43
© 2002 The George Mateljan Foundation