The amino acid called tryptophan is necessary in the diet and is therefore considered to be an essential amino acid as the biochemical synthesis does not occur in the human body. The amino acid is also essential for the biochemical manufacture of the vitamin B3 (niacin) in the human body. Tryptophan is converted into the neurotransmitter serotonin in the brain; this compound is an essential neurotransmitter involved in the transfer of nerve impulses from one neuron to another - it has an important role in generating normal sleep in humans. The amino acid tryptophan therefore aids in stabilizing the mood and combating persistent depression and insomnia in people. The hyperactivity affecting children is also alleviated by this amino acid. Tryptophan also alleviates stress and is considered vital for the health of the heart, it helps in controlling weight and brings about a reduction in appetite, and it also enhances the release of the human growth hormone. Supplements of the amino acid tryptophan are also considered very good for the treatment of severe headaches associated with chronic migraine. Supplements of tryptophan may also reduce some of the effects of nicotine in the brain. The formation of tryptophan in the body requires the presence of a sufficient amount of the vitamin B6 - also called pyridoxine - this vitamin is in its turn essential for serotonin formation. Coronary arterial spasms may be actuated by a deficiency of the amino acid tryptophan and the essential mineral magnesium in the body. Good sources of dietary tryptophan are grains such as brown rice, dairy products like cottage cheese, fruits like bananas, all meats and poultry, peanuts and soy protein, dried dates. Drug stores in the United States do not sell the supplemental form of this amino acid. This is due to a report, dated November 1989, when the U.S. Centers for Disease Control - CDC, came up with evidence linking supplemental L-tryptophan to a form of blood disorder called eosinophilia myalgia syndrome - EMS in short. This is a disease of the blood where patients are affected by an elevation in the white blood cell count and is often accompanied by such physical symptoms as physical fatigue, the presence of muscular aches, various respiratory ailments, problems like edema and a persistent rash. Several hundred cases of this disease were reported, with at least one confirmed death attributable to the outbreak of the disease. The sale of products containing tryptophan was affected following the CDC’s study which established a link between the incidence of the blood disorder and all supplemental products that contained L-tryptophan in the state of New Mexico. Initially, the Food and Drug Administration - FDA of the US warned consumers not to take L-tryptophan supplements without further studies; it then recalled all the marketed products that had L-tryptophan as the sole or a major component in the supplement. This finding was disproved by later research that pointed out that contaminants in the supplements and not the tryptophan, were probably the causative agents for the disorder.