Summary: Mice with dysregulated cytokine IL-23 that consumed diets containing the artificial colorants FD&C Red 40 and Yellow 6 developed colitis, according to a new study.
Source: Mount Sinai Hospital
Researchers at the Icahn School of Medicine at Mount Sinai report that artificial food colorants can trigger intestinal inflammation when the immune system is already out of balance.
Published in Cell Metabolism in May, this study is the first to demonstrate that widely used synthetic food dyes can provoke colitis in an animal model when a specific immune pathway is dysregulated.
In carefully controlled experiments using mice engineered to have altered expression of the cytokine IL-23, investigators observed that animals developed colitis after consuming diets that contained FD&C Red 40 or Yellow 6. By contrast, mice with a normal IL-23 immune profile did not develop inflammatory bowel disease (IBD) when fed the same dye-containing diets.
The research team tested exposure both through food and through drinking water. Mice with dysregulated IL-23 developed disease only after consuming the colorants; when these mice were given dye-free food and water, colitis did not develop. The investigators replicated this outcome across several dietary formulations and with multiple synthetic colorants, strengthening the link between dye exposure and inflammation in the context of IL-23 dysregulation.
Colitis is one form of inflammatory bowel disease, a group of chronic inflammatory conditions of the gastrointestinal tract. Dysregulation of cytokine IL-23 is already implicated in human IBD, and therapies that block IL-23 signaling are used successfully in patients. FD&C Red 40 and Yellow 6 are among the most commonly used synthetic dyes in foods, beverages, and some medications, which raises questions about environmental contributors to disease risk.
Both genetic susceptibility and environmental exposures are thought to influence whether an individual develops IBD, but identifying specific environmental triggers has been challenging. This study provides experimental evidence that, in a susceptible immune setting, common food additives can act as environmental factors that promote intestinal inflammation.
Senior author Sergio Lira, MD, PhD, Leona M. and Harry B. Helmsley Charitable Trust Professor of Immunology at the Precision Immunology Institute at Icahn Mount Sinai, noted the broader context: “The dramatic rise in air and water pollutants and the increased use of processed foods and additives over the past century track with growing rates of inflammatory and autoimmune diseases. These changes likely play a role in disease development, but how they do so is not well understood. We hope this work advances our understanding of how food colorants may affect human health.”
While the mouse findings are clear within the experimental model, it remains uncertain whether the same mechanisms apply to people. The investigators plan further work to define how IL-23 promotes colitis after exposure to synthetic colorants, to identify the molecular and cellular pathways involved, and to determine whether there is relevance to human disease risk or progression.
The study was led by Zhengxiang He, PhD, Instructor of Medicine and Clinical Immunology, and Lili Chen, PhD, Assistant Professor of Medicine and Clinical Immunology at Icahn Mount Sinai. Funding for the research was provided by grants from the National Institutes of Health.
About this immune system research news
Source: Mount Sinai Hospital
Contact: Marlene Naanes – Mount Sinai Hospital
Image: The image is in the public domain
Original Research: The findings are published in Cell Metabolism