Tryptophan

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Tryptophan

Definition

Tryptophan is an amino acid needed for normal growth in infants and for the production and maintenance of the body's proteins, muscles, enzymes, and neurotransmitters. It is an essential amino acid. This means your body cannot produce it, so you must get it from your diet.

Function

The body uses tryptophan to help make melatonin and serotonin. Melatonin helps regulate the sleep-wake cycle, and serotonin is thought to help regulate appetite, sleep, mood, and pain.

The liver can also use tryptophan to produce niacin (vitamin B3), which is needed for energy metabolism and DNA production. In order for tryptophan in the diet to be changed into niacin, the body needs to have enough:

Iron
Riboflavin
Vitamin B6

Food Sources

Tryptophan can be found in:

Cheese
Chicken
Egg whites
Fish
Milk
Sunflower seeds
Peanuts
Pumpkin seeds
Sesame seeds
Soy beans
Turkey

References

Nagai R. Amino acids and proteins. In: Baynes JW, Dominiczak MH, eds. Medical Biochemistry. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 2.

US Department of Agriculture and US Department of Health and Human Services. Dietary guidelines for Americans, 2020-2025. 9th edition. www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf. Updated December 2020. Accessed May 3, 2024.

Snetselaar LG, de Jesus JM, DeSilva DM, Stoody EE. Dietary guidelines for Americans, 2020-2025: understanding the scientific process, guidelines, and key recommendations. Nutr Today. 2021;56(6):287-295. PMID: 34987271. pubmed.ncbi.nlm.nih.gov/34987271/.

Review Date: 5/4/2024
Reviewed By: Stefania Manetti, RDN, CDCES, RYT200, My Vita Sana LLC - Nourish and heal through food, San Jose, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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