Tryptophan: An Essential Amino Acid

Amino acids are the building blocks of protein. It is a two-step process in which amino acids gather and form peptides or polypeptides. From these groupings, proteins are made. A total of 20 different kinds of amino acids form proteins.

One of the best known amino acids is Tryptophan, which is an essential amino acid, meaning it cannot be synthesized by the body and must be ingested through food. Tryptophan is necessary for normal growth in infants and for nitrogen balance in adults. The body also uses tryptophan to help make:

• Niacin (vitamin B3): essential for normal gastrointestinal and nerve processes
• Serotonin: involved in controlling moods and appetite
• Melatonin: important in regulating sleep

In order for tryptophan to be changed into niacin, there needs to be enough B-6, riboflavin, and iron in the body. Niacin, in turn, helps the body produce serotonin, which is a neurotransmitter that acts as a calming agent in the brain and plays a key role in sleep.

Because of its conversion into serotonin, tryptophan is well known for its antidepressant effects. Tryptophan actually increases the amount of serotonin in the blood, unlike antidepressant drugs known as selective serotonin reuptake inhibitors (SSRIs) which only preserve the amounts of serotonin already in circulation.

Recent studies have shown that individuals who are extremely overweight have chronically low levels of tryptophan. Blood levels of tryptophan are also known to fall during intense dieting. This resulting serotonin imbalance may be a contributing factor to eating disorders such as anorexia nervosa.

Study results also show that raising tryptophan levels in the body may decrease appetite, especially for sugars and starchy foods such as bread (carbohydrates). Consuming carbohydrates is known to increase serotonin levels, which in turn makes most people feel less depressed. Therefore, substituting tryptophan for carbohydrates may reduce depressed feelings and help to control the over consumption of these “comfort foods”.

Tryptophan is also involved in the regulation of sleep. Human clinical trials have shown that low levels of tryptophan contribute to insomnia. Consequently, increasing tryptophan may help to normalize sleep patterns. It is important to note, however, that higher than usual levels of tryptophan in the blood have been associated with conditions such as chronic fatigue syndrome. It is unclear whether the high tryptophan levels cause the condition or result from it. More studies are underway to better understand the role tryptophan plays in both depression and sleep disorders.

Foods which can provide an ample amount of tryptophan are:

• Chicken and turkey
• Milk and cheese
• Eggs
• Fish
• Soy
• Tofu
• Pumpkin and sesame seeds
• Peanuts and peanut butter

While turkey does have the making of a natural sedative, it is unlikely that the “calm, want a nap” feeling you have on Thanksgiving Day can be blamed on turkey alone. Nutritionists say that tryptophan actually works best on an empty stomach and only a portion of the tryptophan from the turkey actually makes it to the brain to help produce serotonin. It is, in reality, a combination of the type of food, amount of food, and celebratory atmosphere of Thanksgiving Day that gives you that comfortable feeling.

In 1990, tryptophan supplements were banned because of an outbreak of eosinophilia-myalgia, a syndrome that causes muscle pain and even death. However, the FDA said that contaminated tryptophan supplements caused the outbreak and is was thought to have been limited to products made by only one manufacturer, and the ban was soon lifted.

Certain side effects have been associated with oral supplemental tryptophan such as blurry vision, drowsiness, dry mouth, headaches, and nausea.

Also keep in mind that when tryptophan is used with prescription drugs that promote sleepiness, the effects of the drug may be exaggerated, resulting in sedation or mental impairment.