Groundbreaking research published in the Science Translational Medical Journal this week details a connection between a common food preservative called propionate and the increased risk of obesity and diabetes.

The study was conducted jointly between researchers at Harvard T.H. Chan School of Public Health, Brigham and Women’s Hospital in Boston and Sheba Medical Center at Tel HaShomer in Ramat Gan, Israel.

Researchers examined propionate, a food preservative that is used to extend the life of baked goods, such as bread or cake, by inhibiting the growth of mold. Researchers administered the preservative to mice and discovered that it set off a chain reaction resulting in a hormonal surge, producing more glucose and ultimately hyperglycemia, a defining characteristic of diabetes.

When the researchers gave the mice an amount of propionate that equaled the amount used in a serving of food, the mice gained weight and developed an insulin resistance.

Following this study, the researchers conducted a double-blinded placebo-controlled study on 14 healthy humans. Those who had ingested propionate showed higher levels of certain hormones, including glucagon, indicating that the additive plays a role in the metabolic process, and could potentially be contributing to the rise of obesity and diabetes.

“The dramatic increase in the incidence of obesity and diabetes over the past 50 years cannot be attributed to genetic changes, and involve contributing environmental and dietary factors,” said Dr. Amir Tirosh, director of the Institute of Endocrinology at Sheba Medical Center and one of the researchers of this study. “One such factor that warrants attention is the extensive use of chemicals in the processing, preservation and packaging of foods. We are exposed to hundreds of these chemicals on a daily basis, and most have never been tested for their long-term metabolic effects.”

Though propionate has been approved by the U.S. Food and Drug Administration, this study suggests that alternative methods for food preservation should be explored.