Could a popular food ingredient increase the risk of diabetes and obesity?

According to new research conducted by Harvard TH, the consumption of propionate, a food ingredient widely used in baked goods, animal feeds and artificial flavors, increases the levels of several hormones associated with the risk of obesity and diabetes. Chan School of Public Health in collaboration with researchers from the Brigham and Women's Hospital and the Sheba Medical Center in Israel.

The study, which combined data from a randomized placebo-controlled trial in humans and in mice, indicated that propionate can trigger a cascade of metabolic events leading to resistance. insulin and hyperinsulinemia, a condition characterized by excessive levels of insulin. The results also showed that in mice, chronic exposure to propionate resulted in weight gain and insulin resistance.

The study will be published online in Translational medicine science April 24, 2019.

"Understanding how food ingredients affect the body's metabolism at the molecular and cellular levels could help us develop simple but effective measures to combat the dual epidemic of obesity and diabetes," said Gökhan S. Hotamisligil, Professor of Genetics and Metabolism James Stevens Simmons. Director of the Sabri Ülker Center for Metabolic Research at Harvard Chan School.

More than 400 million people worldwide have diabetes and the incidence rate of diabetes is expected to increase by 40% by 2040, despite considerable efforts to control the disease. The rising rates of diabetes and obesity over the last 50 years indicate that environmental and dietary factors must influence the growth of this epidemic. Researchers have suggested that food components, including ingredients used in food preparation or preservation, may be a contributing factor, but little research has been done on these compounds.

For this study, researchers focused on propionate, a short-chain natural fatty acid that helps prevent the formation of mold on foods. They first administered this fatty acid to mice and found that it rapidly activated the sympathetic nervous system, which resulted in a surge of hormones, including glucagon, norepinephrine, and a gluconeogenic hormone. recently discovered, called fatty acid binding protein 4 (FABP4). . This led the mice to produce more glucose from their liver cells, which resulted in hyperglycemia, a hallmark of diabetes. In addition, the researchers found that chronic treatment of mice with a dose of propionate equivalent to the amount typically consumed by humans resulted in significant weight gain in mice and resistance to the disease. insulin.

To determine how results in mice could translate into humans, the researchers developed a double-blind, placebo-controlled study of 14 healthy participants. Participants were randomized into two groups: one group received a meal containing one gram of propionate as an additive and the other group a meal containing a placebo. Blood samples were taken before the meal, within 15 minutes after the meal and then every 30 minutes for four hours.

The researchers found that people consuming the meal containing propionate had significant increases in noradrenaline, as well as increases in glucagon and FABP4 shortly after the meal. The results indicate that propionate may act as a "metabolic disruptor" that potentially increases the risk of diabetes and obesity in humans. The researchers noted that while propionate is generally recognized as safe by the US Food and Drug Administration, these new findings warrant further research on propionate and alternatives that can be used in food preparation.

"The dramatic increase in the incidence of obesity and diabetes over the last 50 years suggests the involvement of contributing environmental and dietary factors." One factor that deserves our attention is the the ingredients in everyday foods – we are exposed to hundreds of these chemicals daily. " Amir Tirosh, Associate Professor of Medicine at the Sackler School of Medicine, Tel Aviv University, Director of the Division of Endocrinology, Sheba Medical Center, Israel. and researcher at Harvard Chan School.