WASHINGTON -- The Food and Drug Administration called Friday for a nationwide recall on the sale of L-tryptophan, an over-the-counter dietary supplement linked to a mysterious blood and muscle ailment.
An FDA statement issued late Friday urged consumers to stop using dietary supplements containing L-tryptophan, an amino acid, which is widely available in health food stores, supermarkets and drug stores.
FDA field offices on Monday will be asked to notify all manufacturers of the food supplement in their area, asking them to recall the products. Each manufacturer would be expected to contact places where the products are sold.
The action came after federal health officials warned consumers to stop taking L-tryptophan, saying they have received 243 reports in 35 states of a mysterious blood and muscle ailment called eosinophilia-myalgia syndrome, or EMS, that may be linked to the pills.
One death in New York may be linked to EMS, health authorities said.
While the investigation continues into the substance, the FDA, the federal Centers for Disease Control in Atlanta and state health officials have concluded that there is a 'strong, virtually unequivocal link between consumption of L-tryptophan tablets or capsules and the syndrome,' the FDA statement said.
The disease is characterized by an elevated count of eosinophils, a white blood cell, and severe muscle pain and an absence of infection or illness that can explain the symptoms.
Some states, including California, Massachusetts, New York and New Mexico, have taken their own action banning sale of the food supplement following reports this week of health problems associated with L-tryptophan.
Scientists have not determined a cause-and-effect relationship between L-tryptophan and the recent outbreak of EMS, whose symptoms include an unsually high number of white blood cells known as eosinophils, severe muscle pain, weakness, joint pain, swelling of the arms and legs, fever, skin rash and respiratory problems.
But most victims became ill after taking tablets or capsules containing a concentrated form of the amino acid, according to California Health Director Ken Kizer, who noted that the link between L-tryptophan and the illness was 'very strong and very compelling.'
The FDA said that based on all the available information, the disease posed a 'moderate to severe and perhaps life-threatening hazard to certain individuals' and that some victims may suffer chronic after-effects in the future.
Because L-tryptophan, which is manufactured in Japan, is sold as a food supplement rather than a drug, it is not subject to the same stringent testing process as drugs are.
Most major manufacturers and wholesale distributors were expected to voluntarily stop selling L-tryptophan by Friday at the request of the Council for Responsible Nutrition, a trade group that represents about 70 dietary supplement companies.
Doctors are not sure whether the illness has existed for years and escaped detection until it turned up in New Mexico last month, or if it is a new syndrome.
L-tryptophan has been sold in the United States for 30 years, but has grown popular only in the last decade. Some doctors recommend it for people having trouble sleeping, but who want to avoid prescription sleeping pills. The amino acid also reportedly is used by some people for premenstrual syndrome, stress, depression and alcohol and drug abuse.