Is Diacetyl Harmful? 

We are all familiar with the delicious, characteristic taste of butter. Butter naturally contains two compounds that create this flavour: acetoin and diacetyl. This compound is a natural byproduct of fermentation, and because of its buttery flavour, manufacturers often add these chemicals to processed foods to give them an artificial butter flavour. Researchers have linked diacetyl to diseases including popcorn worker's lung (bronchiolitis obliterans), and Alzheimer’s Disease. More research is needed.

What Foods Contain Diacetyl?

Diacetyl is a natural by-product of the fermentation process in certain alcoholic beverages, mainly wine and beer. Brewers may increase or reduce diacetylmorphine during production. These changes affect the beverage's final flavour.

Potential Health Risks of Diacetyl

Manufacturers use this by-product to create buttery flavours in margarine, processed foods, beverages, and oil-based products. It also enhances mouthfeel.

Popcorn Worker’s Lung

In the mid-2000’s, it became apparent that workers in several factories manufacturing artificial popcorn flavouring were coming down with serious lung conditions. Prolonged exposure to the inhalation of diacetyl vapours has been shown to cause bronchiolitis obliterans. In this disease, the normal lung tissue becomes inflamed and scarred, which eventually completely obstructs the airways.  At this time, the only known cure for this disease is a lung transplant. 

Lawmakers introduced safety measures in 2009 and 2010 to protect workers who manufacture diacetyl. Many manufacturers are also voluntarily reducing their use of this compound in products, especially heated products like microwave popcorn, to help prevent exposure to consumers. Microwaving popcorn vaporizes diacetyl. Steam from the bag can release the compound into the air.

Alzheimer’s Disease

There is some preliminary evidence that this compound may also contribute to the progression of Alzheimer’s Disease. It was found that in a test tube, diacetyl increases beta-amyloid aggregation, one of the processes linked to the progressive loss of neurons in the brain.

How Can I Avoid Diacetyl Exposure?

The only proven health risk of this compound is its inhalation over time.  If you simply MUST have your butter flavoured microwave popcorn, then be sure to avoid inhaling the fumes, especially when it is fresh and steaming. Make freshly popped popcorn and add your own butter instead to completely avoid the risk. There is very little evidence that eating this compound is a health concern. Researchers need further studies to confirm the risks. Avoid artificial butter flavouring and some fermented alcoholic beverages to reduce exposure.