New study finds how pesticide exposure causes obesity

BEIJING -- A new study has found that the use of pesticides increases the risk of developing obesity by impairing gut and gut microbiota.

Chlorpyrifos has been a residential insecticide since the late 19th century, and it is still among the most commonly used type of pesticide around the world due to its ideal bioactivity. Previous studies show that exposure to the pesticide may cause obesity and diabetes, but the underlying mechanism of how it works remains unknown.

Researchers from China Agriculture University focused on the human gut microbiota, the most important micro-ecosystem in the body.

Gut microbiota, containing tens of trillions of microorganisms, has important effects including in immunity and body weight. It can help the body digest certain foods that the stomach and small intestine have not been able to digest.

In animal experiments, researchers put the pesticide into the food and water of mice. They found the pesticide intake broke the integrity of the gut barrier, leading to an increased entry of a toxin into the body and finally inflammation, which ultimately induced insulin resistance and obesity.

Insulin resistance is commonly seen in obese people and plays a key role in the development of diabetes.

According to Wang Peng, lead researcher, the increased toxin-bearing bacteria population in the body further disrupts the gut microbiota balance, making the mice gain more fat.

Moreover, similar results were observed in mice with different genetic backgrounds and diet habits, indicating that genes and diet had limited influence on the altered gut and gut microbiota.

The research was published in the international journal Microbiome.

"Our results suggest that widespread use of pesticides may contribute to the worldwide epidemic of inflammation-related diseases," Wang said.