Eosinophilia-myalgia syndrome associated with exposure to tryptophan from a single manufacturer

Article Abstract:

Eosinophilia-myalgia syndrome (EMS) is a condition that has been identified only recently. It is characterized by severe myalgia (muscle pain) and an increase in the number of eosinophils (a type of white blood cell), and is associated with the use of tryptophan (a health food supplement). To determine whether tryptophan itself, some factor in the manufacture or distribution of the compound, or some factor in the patients who contracted EMS, is critical for the development of the disorder, an epidemiological study was performed. Information regarding age, sex, symptoms, overall medical condition, use of food supplements other than tryptophan, and tryptophan use was obtained from 58 people with EMS (cases), 30 asymptomatic control subjects, and 63 tryptophan users without EMS symptoms. Selection of cases and controls was based on carefully constructed epidemiological criteria. Twenty-two (38 percent) of the cases had taken tryptophan from the same retail lot, but other cases had taken tryptophan from other lots. Additional product tracing back toward the source of the product was performed for 46 cases and 41 controls, and it was discovered that 45 of the cases had taken tryptophan made by manufacturer X in Japan. Moreover, most of the raw product lots that were case-associated had been produced between January and May 1989. Thus, it appears that EMS is the result of contamination or defective production of a subset of tryptophan; EMS was not caused by the compound itself. Samples of tryptophan from the suspect lot are under analysis by the Centers for Disease Control. Other factors are also consistent with recent contamination as the cause. Similarities between EMS and the illness that developed in 1981 in people who ingested toxic rapeseed oil are discussed, and possible physiologic effects of such contamination are reviewed. (Consumer Summary produced by Reliance Medical Information, Inc.)

Complications and side effects, Health foods, Natural foods, Food contamination

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Analysis of L-tryptophan for the etiology of eosinophilia-myalgia syndrome

Article Abstract:

Eosinophilia-myalgia syndrome (EMS) is characterized by an elevated number of eosinophils and severe muscle pain. The majority of EMS cases have been associated with the ingestion of dietary supplements of L-tryptophan, an essential amino acid. Since many of these patients used the product of a single manufacturer, it is widely suspected that the cause of the syndrome is a contaminant, and not tryptophan itself. Chemical analysis of the implicated tryptophan supplements has uncovered the presence of chief suspects in the etiology of EMS. Using HPLC, or high-pressure liquid chromatography, investigators could separate the closely-related chemicals in the tryptophan product. One particular ''peak'' on the analysis chart seemed to be especially associated with the batches of L-tryptophan that seemed to cause EMS. Further analysis revealed that the molecule represented by the peak had a molecular weight exactly twice that of tryptophan, plus two carbon atoms and two hydrogen atoms. The researchers believe that this is likely to be two tryptophan molecules joined by acetaldehyde to form a compound with the chemical name di-tryptophan aminal of acetaldehyde. Ongoing investigation has revealed other suspects in the tryptophan product, as well. Another suspect is 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid. The only way that any of these contaminants can be conclusively demonstrated to be the cause of EMS, however, is through the development of an animal model. Preliminary results suggest that researchers can produce an EMS-like syndrome in laboratory rats. Further research will determine if this experimental model will prove useful in understanding the cause and development of eosinophilia-myalgia syndrome. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan - United States, through August 24, 1990

Article Abstract:

The Centers for Disease Control (CDC) are charged with the responsibility of collecting data on significant health issues in the United States. Among these issues is the recent appearance of the syndrome now called eosinophilia-myalgia syndrome (EMS). This syndrome involves elevation of the levels of eosinophils, a type of white blood cell, and severe muscle pain. The CDC has established eosinophils greater than 1,000,000 per milliliter and debilitating muscle pain as the required diagnostic criteria for reporting EMS. As of August 24, 1990, the CDC identified 1,536 cases of EMS in the United States, including Washington, D.C. and Puerto Rico. Twenty-seven deaths were reported. The syndrome seems to be associated with the use of L-tryptophan, an essential amino acid, as a dietary supplement; tryptophan ingestion was reported in 96 percent of the cases. The FDA has recalled all supplements of L-tryptophan that supply more than 100 milligrams per day, but some cases of EMS developed after the recall. This suggests that some people are either unaware of the hazard or have chosen to disregard the warnings and the recall. Since the definition of EMS set down by the CDC is somewhat stringent, clinicians should be aware that any alteration in eosinophil count, or myalgia, associated with tryptophan ingestion, may be a variation of EMS and should be monitored appropriately. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, Dietary supplements

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