New research suggests that common food additives called emulsifiers may have lasting effects on health across generations. Scientists found that when mother mice consumed dietary emulsifiers before and during pregnancy, the gut microbiomes of their offspring changed early in life. These changes disrupted immune development and raised the risk of inflammation and metabolic issues later on.

What the study found

Researchers from the Institute Pasteur and Inserm conducted the study in laboratory mice. They gave female mice two widely used emulsifiers — carboxymethyl cellulose (E466) and polysorbate 80 (E433) — for ten weeks before pregnancy and continued during pregnancy and breastfeeding.

The key finding was that offspring of these mothers displayed noticeable changes in their gut microbiota within the first weeks of life. These changes occurred despite the offspring never consuming emulsifiers directly.

How gut microbiota changed

The altered microbiome included higher levels of flagellated bacteria. These bacteria are known to activate immune responses and promote inflammation. Scientists also observed increased bacterial contact with the gut lining, a pattern called “encroachment.”

Under normal conditions, certain pathways allow small bacterial fragments to cross the gut lining. This helps the immune system learn to tolerate friendly microbes. However, in the offspring of emulsifier-exposed mothers, some of these pathways closed too early.

The result was a disruption in communication between the gut microbiota and the immune system. As the animals reached adulthood, this led to overactive immune responses, chronic inflammation, and a higher risk of disorders like inflammatory bowel disease and obesity.

Why this matters for health

This research shows that substances added to food may influence not just the direct consumer, but also future generations. In humans, emulsifiers are common in processed foods, including dairy items, baked goods, ice cream, and even some infant formulas.

“It is crucial for us to develop a better understanding of how what we eat can influence future generations’ health,” said Benoit Chassaing, lead author of the study. “These findings highlight how important it is to regulate the use of food additives.”

Researchers urge clinical trials in humans to explore how early-life exposure to emulsifiers affects the gut microbiota, immune development, and long-term disease risk.

Study background and publication

The research was funded by grants from the European Research Council (ERC) and published in the peer-reviewed journal Nature Communications. It taps into a growing field of interest — how diet shapes not only the gut microbiome but also lifelong health outcomes.