Excerpts from “Tryptophan: Powerful Serotonin Booster,” by barbra Wexler, MPH
Chances are you’ve heard of L-tryptophan, the biologically active form of the amino acid tryptophan, so let’s find out why tryptophan is “essential” and what it does in the body.
Tryptophan is found in many animal and plant proteins and is considered essential because it’s not produced by the human body; we have to get tryptophan, along with eight other essential amino acids, from outside sources, i.e. our diet or a nutritional supplement.
Tryptophan is a building block that the body uses to make 5-hydroxytryptophan (5-HTP), an aromatic amino acid that is a precursor of serotonin, an important neurotransmitter. Neurotransmitters are naturally occurring chemicals in the brain that transmit messages from one nerve cell to another. Serotonin is involved in thought, emotions and behavior, and in the production of melatonin, a neurohormone associated with regulating sleep-wake cycles.
The Role of Tryptophan in Human Health
Tryptophan is an organic compound, 1 of 20 amino acids commonly found in animal sources of protein. It’s formed from proteins during digestion by the action of proteolytic enzymes, substances produced by the pancreas that break ingested proteins down into peptides or amino acids.
Tryptophan is necessary for normal growth and development of infants and for nitrogen balance in adults. Nitrogen balance refers to the relationship between nitrogen taken into the body, usually as food, and nitrogen excreted from the body. A negative nitrogen balance means that some parts of the body, such as muscles, are breaking down faster than they are replaced.
Supplemental tryptophan is available as L-tryptophan, the biologically active form of the amino acid. It is also important to understand that for humans, only L-tryptophan is effective; the D-isomer, or acetyl-D form, of tryptophan is not useful. L-tryptophan has been used to treat sleep problems, such as insomnia, and to improve the quality and duration of sleep. It also has been used to aid relaxation and to relieve symptoms of occasional anxiety, depression and menstrual discomfort.
L-tryptophan may also be helpful for relieving migraine headaches and may assist with weight management, smoking cessation and attention deficit disorder.
In addition, tryptophan is necessary for the production of niacin. Also known as vitamin B3, niacin supports healthy skin, nerves and digestion.
Dietary Sources of Tryptophan
Foods rich in tryptophan include bananas, chocolate, cottage cheese, dried dates, fish, meat, milk, oats, peanuts and turkey. Other dietary sources with lower concentrations of tryptophan include corn, cereal grains, legumes (peas and beans), flesh foods, eggs, dairy products, some nuts and seeds and the casein component of milk. A 3-ounce serving of meat, tuna or peanuts contains about 300 milligrams of tryptophan.
Human breast milk is also a potent source of tryptophan. In fact, some studies have found that breast-fed infants have higher plasma tryptophan concentrations than formula-fed infants, despite the higher protein concentration of formulas.
Higher plasma concentrations of tryptophan may help explain the lower food intake of breast-fed infants. Because breast-fed infants and those fed formula rich in lactalbumin have higher plasma concentrations of tryptophan than of other amino acids, it is predictable that their brain tryptophan concentrations would be higher. Tryptophan is a precursor for the synthesis of serotonin, and increased synthesis and release of serotonin likely improve infants’ satiety.
Stress Compromises Heart Health, Immunity, and Healing
One of the most popular uses of L-tryptophan is as an aid to relieve stress and promote relaxation. There is a wealth of medical and scientif- ic literature that provides evidence linking serotonin, tryptophan and 5-HTP with reduced stress and depression. We’ve all experienced stress at one time or another. Although it may be hard to precisely define, stress has something to do with being pushed beyond our limits. Stress is any influence that engages and challenges our physical, mental, emotional or spiritual capacity for adaptation. It is what we feel when circumstances force us beyond our natural ability to respond and adapt, challenging us to regain a sense of balance and normalcy in our lives.
The relationship between stress and cardiovascular disease is complicated. Does being a workaholic or having a Type A personality cause heart disease? Does stress raise blood pressure? Although there are many opinions about the exact nature of the relationship between stress and heart disease, research has shown that stress does contribute to heart disease in some people.
Stress may not directly cause high blood pressure, high cholesterol or other cardiac risk factors, but it can exacerbate them. What’s even worse is that many of the lifestyle choices people make when they are under stress—smoking, overeating and consuming alcohol—independently increase risk for cardiovascular disease.
Scientists have known for years that major, acute stressors and chronic life stress can compromise immune function and increase susceptibility to disease. Stress increases your susceptibility to several types of infections, from the common cold to tuberculosis, as well as to autoimmune disorders, in which the body produces immune responses against its own cells.
The immune system relies on two types of white blood cells—neutrophils, the larger and more numerous white blood cells involved in fighting infection, and leukocytes, the main fighter cells. There are three kinds of leukocytes—lymphocytes, monocytes and granulocytes— each with its own unique function.
Stress-induced increases in hormone levels affect the immune system in two ways: first, they increase the quantity of neutrophils; second, they decrease the quantity of lymphocytes, which produce antibodies and other substances that fight infection and disease.
As a result of these altered levels of white blood cells, chronic stress can prolong healing and recovery from illness or injury. Laboratory and clinical studies have demonstrated that psychological stress is associated with slower healing of injuries and surgical wounds and with more complicated postoperative recovery.