Diacetyl, an ingredient used in microwave popcorn to get that buttery flavor, can up the risk of Alzheimer's disease according to a new study.

Researchers say that diacetyl intensifies the effects of a key protein's toxicity. The protein, B-Amyloid, is known to be associated with AD.

Aside from popcorn, diacetyl is used in candy, baked goods, pet foods, margarines and snack foods. The distinctive buttery smell and taste are due to this additive.

Diacetyl is regarded as a safe additive in foods by the Food and Drug Association. However, a toxicology report published in March 2012, states that exposure to artificial butter flavoring containing diacetyl can lead to rare but severe form of lung disease, Bronchiolitis obliterans or "popcorn lung", in workers at popcorn plants.

Researchers in the present study say that chronic exposure to diacetyl can increase risk of developing AD in the thousands of workers who are exposed to this chemical every day.

They found that the structure of diacetyl is similar to B-Amyloid, which clumps together in the brain. It is this clumping of B-Amyloid's that leads to AD.

Diacetyl increased clumping of the protein in lab experiments. Researchers say that it is possible that people in ‘real life’ work-setting could be exposed to increased levels of diacetyl which could aid the clumping of the protein in the brain.

Also, they found that diacetyl could easily penetrate the "blood-brain barrier," a protective feature that keeps toxins from entering the brain.

Diacetyl was found to suppress a protein, glyoxalase l, known to safeguard the cells in the brain.

"Whether toxic levels of diacetyl are achieved in various body compartments upon mere (over) consumption of diacetyl-containing food substances is an unanswered but an important question," Robert Vince from University of Minnesota and colleagues said in an American Chemical Society's news release.

The study was published in the journal Chemical Research in Toxicology.