Amino acids can reduce depression

Better Nutrition (1989-90), Feb, 1989 by Deborah Seymour Taylor

Amino Acids Can Reduce Depression

As early as 1951 the Handbook of Nutrition, published by the American Medical Association, stated "Life histories of patients have shown that the earliest effects of nutritive deficiency are not found first in physical ailments, but rather in the mental depression, nervous instability and other forms of personality changes.

The National Institute of Mental Health, Washington, has estimated that approximately 10 million adult Americans currently suffer from chronic depression, characterized by sadness, inactivity, difficulty concentrating and a decrease in appetite. Although many struggle to live "normal" lives, an alarmingly high number -- up to 15 percent -- will eventually commit suicide.

Current research suggests minerals, amino acids and vitamins can alter the biochemistry of the brain and prompt positive changes in behavior. "Today, we no longer ask the foolish question, 'Is there a biochemistry of depression?' Rather, we ask 'What are the biochemical characteristics for each specific type of depression?'" wrote Eric R. Braverman, M.D. and Carl C. Pfeiffer, M.D., in The Healing Nutrients Within.

Researchers first suspected that extreme mood changes might be biochemical in nature in the 1950s, when patients taking reserpine for high blood pressure developed severe depression. Other patients on iproniazid for tuberculosis, experienced mood elevations. After extensive research, scientists discovered that reserpine worked by reducing neurotransmitter levels in the brain, while iproniazid increased them. The studies suggested neurotransmitter levels were somehow linked to mood swings.

Neurotransmitters are "chemical messengers" that transmit information through the central nervous system. The nerve cells, or neurons, that make up the system are separated by a gap called a synapse. Neurotransmitters, acting as carriers, transmit nervous impulses across this synapse to the adjacent neuron. Scientists have found that low levels of certain neurotransmitters -- particularly serotonin and norepinephrine -- can cause depression.

According to Drs. Braverman and Pfeiffer, specific amino acids are required for the formation of neurotransmitters. "The central nervous system is almost completely regulated by amino acids," they said. As such, "amino acid therapies are revolutionizing the treatment of psychiatric disease. Serotonin levels are dependent on dietary intake of tryptophan and dietary intake directly influences the amount of neurotransmitter in the brain."

In a study reported in the British Medical Journal, researchers Bapuji Rao and A.D. Broadhurst administered tryptophan in tablet form to nine patients, all suffering from depression severe enough to warrant hospitalization. Seven patients were given a pharmaceutical antidepressant medication. Both groups showed major improvement over a four-week period, with significant mood elevation. Researchers concluded that the natural amino acid tryptophan was as effective as the prescription drug in relieving severe depression.

Another tryptophan study reported in the Lancet was a collaborative effort of nine Scandinavian doctors. A group of 42 patients with serious recurrent depression participated in the double-blind study, during which researchers concluded that both drug therapy and amino acid therapy showed highly significant results, with less frequent side effects in the tryptophan group.

Another neurotransmitter that has been implicated in mental health is norepinephrine. Researchers have found that low levels of this brain chemical are associated with depression. But without the amino acid tyrosine, the body cannot synthesize it. In studies conducted at the Brain Bio Center, Skillman, N.J., Drs. Braverman and Pfeiffer administered tyrosine to a woman suffering from severe depression. The 22-year-old former student had been forced to drop out of college because of her extreme depression. When she came to the Center she weighed only 92 pounds. "When she was started on tyrosine therapy, as much as 6 grams per day, it began to lift her out of her depression," the doctors wrote. "Gradually, [her depression] subsided and she went back [to school] to train as a nurse. With the increasing prevalence of side effects from antidepressants, tyrosine has become very attractive."

Also critical in the synthesis of both serotonin and norepinephrine is vitamin B6 (pyridoxine). This vitamin acts as a coenzyme in amino acid metabolism and is necessary to the formation of nerve cells. According to Alan Gaby, M.D., author of The Doctor's Guide to Vitamin B6, "vitamin B6 (pyridoxine) is necessary in certain vital enzyme reactions that occur in the brain in the formation of these neurotransmitters involved in mood. If the body's amino acids can simply be given a little 'boost' with vitamin B6 [it seems] lesser amounts of tryptophan or tyrosine might do the job, especially since the amino acids alone may not work in some cases."

Scientific evidence of the role B6 plays in depression also comes from a report published in Nutrition Reports International. Investigators at the Virginia Polytechnic Institute, Blacksburg, and the National Institute of Mental Health found that B6 deficiency may be quite common in depressed individuals. Using an enzyme stimulation test to measure B6 levels, they found that all the depressed patients and none of the controls were deficient.