Still Searching for Better Butter Flavoring

Food Additives still searching for Better Butter FlavoringAfter diacetyl (2,3-butanedione) was shown to cause bronchiolitis obliterans in workers who inhaled high levels of this volatile butter flavoring at microwave popcorn processing plants, 1,2,3 some manufacturers switched to a substitute assumed to be safer.Recent rodent studies, however, suggest that the substitute, 2,3-pentanedione, may be as damaging to the respiratory tract as the diacetyl it replaced. 4,5ronchiolitis obliterans, or "popcorn lung," is a rare, irreversible, debilitating lung disease in which inflammation and scarring obstruct the smallest airways, the bronchioles.There is no good treatment for the disease short of a lung transplant. 6ronically, lung transplant itself can trigger bronchiolitis obliterans through organ rejection mechanisms, limiting the survival of many transplant patients. 7fter the disease was identified in popcorn workers, researchers at the National Institute for Occupational Safety and Health (NIOSH) reported bronchial epithelial damage in rats inhaling vapors of butter flavoring. 8This type of injury causes fibrosis (thickening and scarring) of the bronchioles, which is the underlying cause of bronchiolitis obliterans.In 2008 some of the same NIOSH researchers narrowed their studies to diacetyl, a major component of butter flavoring vapors, and reported similar acute damage in rats. 9he same year, Daniel Morgan, head of the Respiratory Toxicology Group at the National Institute of Environmental Health Sciences, and colleagues reported that mice develop bronchial epithelial damage after inhaling diacetyl vapors at concentrations equivalent to worker exposures. 6Rats proved even more susceptible than mice and developed full-blown bronchiolitis obliterans after repeated exposure to diacetyl. 4,10ecause diacetyl and 2,3-pentanedione,