Researchers from American Chemical Society found that the ingredient, diacetyl (DA) used to produce the distinctive buttery flavour and aroma of microwave popcorn, margarines, snack food, candy and other products has an architecture similar to a substance that makes beta-amyloid proteins clump together in the brain forming plaques.
The research found that DA increased the level of beta-amyloid clumping.
Other lab experiments showed that DA easily penetrated the so-called "blood-brain barrier," which keeps many harmful substances from entering the brain.
DA also stopped a protective protein called glyoxalase I from safeguarding nerve cells.
"In light of the chronic exposure of industry workers to DA, this study raises the troubling possibility of long-term neurological toxicity mediated by DA," researchers said in a statement.
The study was published in journal Chemical Research in Toxicology.
Robert Vince and colleagues Swati More and Ashish Vartak explained that DA has been the focus of much research recently because it is linked to respiratory and other problems in workers at microwave popcorn and food-flavouring factories.