Researchers at the Institut Pasteur and Inserm discovered that common food emulsifiers consumed by mother mice altered the gut microbiome of their offspring from the first weeks of life, potentially leading to long-term health consequences. The study, published December 26, 2025, revealed that these changes interfered with normal immune system development, resulting in chronic inflammation. As adult mice, the offspring exhibited increased susceptibility to gut disorders and obesity.

The research highlights the possibility that food additives may have previously unrecognized, lasting effects that extend beyond the individuals who directly consume them. The team focused on dietary emulsifiers, which are widely used in processed foods to improve texture and prevent separation of ingredients.

"We observed that maternal consumption of emulsifiers significantly reshaped the gut microbiota of their offspring," said Dr. Clara Delaroque, a researcher at the Institut Pasteur and lead author of the study. "This early alteration disrupted the delicate balance of bacteria in the gut, impacting the development of a healthy immune system."

The gut microbiome plays a crucial role in training the immune system to distinguish between harmless and harmful substances. Disruptions to this process can lead to chronic inflammation, a key factor in the development of various diseases, including inflammatory bowel disease (IBD) and metabolic disorders like obesity.

Dr. Benoit Chassaing, another researcher involved in the study, explained that the altered gut microbiota in the offspring led to increased permeability of the intestinal lining, often referred to as "leaky gut." This allows molecules to pass through the colon epithelium, triggering an inflammatory response. "The impaired gut barrier function and subsequent inflammation contributed to the increased vulnerability to gut disorders and obesity observed in the adult offspring," Chassaing said.

While the study was conducted on mice, the researchers believe the findings have important implications for human health. "The widespread use of emulsifiers in the modern diet raises concerns about their potential impact on the developing gut microbiome of infants and children," Delaroque noted.

Medical experts emphasize that more research is needed to fully understand the effects of emulsifiers on human health. Dr. Emily Carter, a gastroenterologist not involved in the study, commented, "This research provides a compelling reason to investigate the long-term effects of food additives on the gut microbiome and immune development in humans. It underscores the importance of a balanced diet, especially during pregnancy and early childhood."

The findings suggest that pregnant women and young children may be particularly vulnerable to the effects of emulsifiers. Health professionals recommend that individuals focus on consuming whole, unprocessed foods whenever possible to minimize exposure to these additives. Further research is planned to identify specific emulsifiers that pose the greatest risk and to explore potential interventions to mitigate their effects on the gut microbiome.