Toxins, Gut Microbiome and Kids: New Study Scratches Surface of Possible Big Link

Scientists from numerous fields have recently begun investigating the role that our digestive tract microbiome (bacteria, fungus and viruses) play in a variety of adverse health conditions as well as overall health and well-being. Now researchers have completed the most comprehensive study to date on how a class of persistent toxins called semi-volatile organic compounds (SVOCs) are associated with the gut microbiome in human children.

SVOCs are a broad class of odorless chemicals that are emitted from building materials and consumer products, often slowly evaporating and settling on dust particles and water droplets. Almost everyone in the developed world is exposed regularly to at least some of these compounds, due to their common use in industrial and consumer products.

Children typically have higher exposure rates, due to spending more time playing on dusty floors where SVOCs accumulate, and because their growing bodies are more susceptible to novel environmental stressors. Of importance is the fact that the gut microbiome has been shown to have a clear importance to childhood development, as well as adult health. While some studies have already shown that certain SVOCs have an impact on the gut microbiome of children, the chemicals studied are just a tiny fraction of those that people are routinely exposed to. According to one of the researchers in this study, Dr. Courtney Gardner, “…we need to get a sense of which SVOC classes seem to be the most negatively associated with microbiome communities.”

Study overview

Researchers measured the levels of dozens of SVOCs circulating in the bodies of almost 80 children between the ages of three and six. They also characterized each of the children’s gut microbiome and then looked for relationships between the differences they found and exposures to SVOCs.

Study findings overview

The researchers found 29 SVOC compounds in more than 95% of the samples taken. They also found relationships between the compounds present in children’s blood or urine and the relative amounts of key microbes, including 61 bacteria and 24 fungi. After working through the various biomarkers and relationships, the researchers discovered that children with high levels of halogenated SVOCs have some unusual guests in their guts…

Takeaway

The results demonstrated that certain SVOCs are correlated with the abundance of bacterial and fungal species living in the human digestive tract and may affect them differently, providing a potential mechanism for measuring exposure to a wide variety of these substances. The study also suggests that exposure to toxic halogenated compounds–chemicals containing carbon and a halogen such as chlorine and bromine–may create a niche for bacteria that feed off of them. It should be noted that these bacteria are not usually found in the human digestive tract.

“We found bacteria that researchers use for soil bioremediation to remove chlorinated solvents, which is not an organism that you would expect to find in somebody’s gut.”                                    

-Dr. Claudia Gunsch, researcher, Theodore Kennedy Professor of Civil and Environmental Engineering, Duke University


Journal Reference:  Courtney M. Gardner, Kate Hoffman, Heather M. Stapleton, Claudia K. Gunsch. Exposures to Semivolatile Organic Compounds in Indoor Environments and Associations with the Gut Microbiomes of Children. Environmental Science & Technology Letters, 2020;

DOI: 10.1021/acs.estlett.0c00776