Robert Vince, director of the Center for Drug Design at the University of Minnesota, and colleagues Swati More and Ashish Vartak said diacetyl has been the focus of research recently because it is linked to respiratory and other problems in workers at food-flavoring factories.
Vince's team said it realized diacetyl has an architecture similar to a substance that makes beta-amyloid proteins clump together in the brain -- this clumping is the hallmark of Alzheimer's disease.
The study, published in the journal Chemical Research in Toxicology, found diacetyl increased the level of beta-amyloid clumping. In addition, the study found at real-world occupational exposure levels, diacetyl also enhanced beta-amyloid's toxic effects on nerve cells growing in the laboratory.
Other laboratory experiments also showed diacetyl easily penetrated the "blood-brain barrier," which keeps many harmful substances from entering the brain, Vince said.
"In light of the chronic exposure of industry workers to diacetyl, this study raises the troubling possibility of long-term neurological toxicity mediated by diacetyl," the researchers said in a statement.
Several U.S. microwave popcorn brands removed diacetyl in 2007 and 2008 and substituted another butter flavoring.