Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome.
Level 5 - mechanism / opinion, no new human data
Bench analytical chemistry research with no human clinical outcome data
PubMed 29800716 · doi:10.1016/j.toxlet.2018.05.027
What was done
Using online HPLC-electrospray ionization mass spectrometry (LC-MS) and precursor/product ion tandem mass spectrometry (MS/MS), the authors characterized a homologous family of condensation products related to Peak AAA isomers (AAA 1-343 and AAA 2-343) present in Showa Denko L-tryptophan associated with the 1989 eosinophilia-myalgia syndrome (EMS) outbreak.
What was found
The authors structurally characterized eight new homolog contaminants (AAA 1-XXX and AAA 2-XXX) formed by condensation of L-tryptophan with bacterial cell membrane fatty acids: AAA 1-315 (5-methylheptanoic acid, anteiso-C8:0), AAA 2-315 (n-octanoic acid, n-C8:0), AAA 1-329 (6-methyloctanoic acid, anteiso-C9:0), AAA 2-329 (n-nonanoic acid, n-C9:0), AAA 1-385 (10-methyldodecanoic acid, anteiso-C13:0), AAA 2-385 (n-tridecanoic acid, n-C13:0), AAA 1-399 (11-methyltridecanoic acid, anteiso-C14:0), and AAA 2-399 (n-tetradecanoic acid, n-C14:0). Contaminant concentration levels were estimated at 0.1-7.9 µg per 500 mg of an individual L-tryptophan tablet or capsule.
Why it matters
This study identifies a wider family of trace bacterial-derived lipid condensation contaminants in historical EMS-associated L-tryptophan, providing structural parallels to investigate alongside related conditions such as Spanish Toxic Oil Syndrome.
Limits
The study is restricted to analytical chemistry and mass spectrometry. It contains no biological, toxicological, or clinical assays to evaluate whether these specific newly identified homologs causally trigger eosinophilia-myalgia syndrome in humans or animals. The total number of supplement samples tested is not reported in the abstract.
Cited by
- supports Contaminated tryptophan batches originating from Japan caused severe illness and death, leading to a long-term ban on its sale.