A recent study has proposed a model linking the butter flavoring known as diacetyl to bronchiolitis obliterans syndrome, a lung disease diagnosed in microwave popcorn plant workers. James Mathews, et al., “Reaction of the Butter Flavorant Diacetyl (2,3-Butanedione) with N-α-Acetylarginine: A Model for Epitope Formation with Pulmonary Proteins in the Etiology of Obliterative Bronchiolitis,” Journal of Agriculture and Food Chemistry, November 2010. Researchers with RTI International and the National Institute of Environmental Health Sciences evidently analyzed the effects of diacetyl on N-R-acetylarginine in an effort to understand how the chemical reacts with cell membranes containing the amino acid arginine. According to the study abstract, “Because diacetyl modifies arginine residues, an immunological basis for its toxicity is under investigation.”

“Currently, the mechanism(s) of diacetyl toxicity (are) unknown; however, the results of this study suggest that injury to the airway epithelium may involve alteration of cellular proteins containing arginine, including those on cell membranes,” wrote the authors.