Contaminant Found in Herbal Remedy
In a new analysis of several samples of the dietary supplement 5-HTP made public today, Mayo Clinic scientists found traces of a chemical they say is linked to a sometimes deadly immune-system disease.
The scientists analyzed six store-bought samples of 5-HTP, an increasingly popular supplement touted as a natural remedy for mild depression, anxiety and sleeplessness.
All the samples tested contained very small amounts of a chemical contaminant implicated in a notorious 1991 case of a painful white blood cell disease called eosinophilia-myalgia syndrome.
The presence of the contaminant in retail products raises the possibility that consumers may be at risk of developing the disease, said Stephen Naylor, a Mayo Clinic pharmacologist, who led the analysis.
“Our findings give very real cause for concern,” he said. “We would absolutely recommend that consumers don’t take high doses of this supplement.”
Researchers are especially concerned because the findings hark back to an outbreak of the disease in the late 1980s. That was linked to a similar supplement, tryptophan.
Federal researchers have reported that at least 30 people died and 1,500 developed the immune-system disease after ingesting tryptophan supplements with numerous impurities.
After the Food and Drug Administration banned those tryptophan supplements, companies started promoting 5-HTP, or 5-hydroxy-tryptophan, as a substitute.
Both compounds, known as amino acids, are used by the human body to synthesize the neurochemical serotonin, which helps regulate mood. Some researchers say that taking the supplements may ease anxiety and facilitate sleep by boosting serotonin levels.
The new results are based on the case of a Canadian woman who developed eosinophila-myalgia syndrome in 1991 after being exposed to small amounts of 5-HTP. When the Mayo Clinic scientists analyzed some 5-HTP the woman was exposed to, they identified a chemical in it that may have caused the disease.
Then, analyzing 5-HTP supplements bought in Minneapolis and New York City, the scientists found that the products had 3% to 15% of the same chemical contaminant, known as “peak X,” because it appears as a peak on the instrument used to analyze the substance.
The scientists, who published their findings as a letter to the journal Nature Medicine, did not provide the brand names of the supplements tested.
An FDA spokeswoman said the agency was repeating the Mayo tests but had no comment on the matter.
The findings are a “matter of concern,” said Annette Dickinson, director of scientific and regulatory affairs at the Council for Responsible Nutrition, an industry trade group. “This might be dealt with by improved [manufacturing practices] to assure that the peak does not show up.”
