Tryptophan
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.
Amino acids are either essential, which must be supplied by food, or nonessential, which are made in the body.
The U.S. Department of Agriculture's newest food guide, called MyPlate, encourages consumers to make healthier food choices. The guide encourages you to make healthy choices and avoid oversized portions. Half your plate should be filled with fruits and vegetables. At least half of your grains should be whole grains. You also should switch to fat-free or low-fat milk.
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, Taniguchi N. Amino acids and proteins. In: Baynes JW, Dominiczak MH, eds. Medical Biochemistry. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 2.
United States Department of Health and Human Services; United States Department of Agriculture. 2015-2020 Dietary Guidelines for Americans. 8th ed.
Version Info
Last reviewed on: 2/4/2022
Reviewed by: Meagan Bridges, RD, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
