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Study finds first evidence linking exposure to household chemicals to changes in the gut health of children
A study out of Washington State University, in collaboration with Duke University, has found the first evidence linking exposure to household chemicals with impacts on the gut microbiomes of children.
Published in the journal Environmental Science and Technology Letters, the pioneering study could lead to better awareness of the hazards of repeated exposures to common chemicals generally regarded as safe for use in the home.
Chemicals at Home: A Veiled Threat
The study,[i] based in North Carolina and funded by the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences, sought to gauge the average toddler's exposure to semivolatile organic compounds (SVOCs) in the indoor environment.
Researchers measured levels of SVOCs in urine, blood and fecal samples obtained from 69 children between the ages of 3 and 6 years. Mothers and children were enrolled as a cohort from participants in the larger Newborn Epigenetics Study (NEST). Medical data for each child was obtained from NEST records.
Among the chemicals detected in the children's biological samples were phthalates, found in consumer plastics and personal care products like soap and lotion, and per- and polyfluoroalkyl substances (PFASs), found in the coatings on cookware, carpets and furnishings, as well as in paint, cleaning products and more.
Toddlers More Susceptible to Chemical Exposures
Extensive data were collected from mothers regarding their child's home environment, diet, health, and behavior, with dietary questions limited to potential exposures to PFAS and phthalates. Common sources of dietary exposure to these chemicals include foods in single-use plastic or microwavable packaging, and frequent restaurant meals, as many restaurants serve food that has been stored in plastic containers.
Blood and urine samples were analyzed for 44 SVOC biomarkers, including organophosphate esters, parabens, phenols, antimicrobials, phthalate compounds and PFASs. Fecal samples were tested for the presence of bacterial and fungal colonies that indicate the health of the human gut microbiome.
After analyzing the samples, researchers found that children with higher levels of certain chemicals in their bloodstream had lower amounts of specific bacterial colonies and less bacterial diversity in their gastrointestinal tract. Specifically, higher levels of PFASs in the blood correlated to a reduction in types and numbers of certain bacterial strains, and increased phthalates were associated with reduced fungal populations.[ii]
The Microbiome Works to Maintain Balance
Researchers were surprised to discover the presence of several types of dehalogenating bacteria in the guts of children with high levels of chemical exposures.[iii] Dehalogenating bacteria are a class of bacteria often used to remediate persistent chemical contaminants in the soil and groundwater.[iv] Dehalogenating bacteria are not commonly found in the human gut.
According to the study, this appears to be an attempt by the microbiome to self-regulate an environment under attack from chemicals. According to Courtney Gardner, lead author on the study, "Finding the increased levels of these type of bacteria … means that, potentially, the gut microbiome is trying to correct itself."[v]
According to Gardner, the correlation between chemical exposure and less abundant bacterial organisms in the gut was the most pronounced takeaway from the study, and potentially the most concerning.[vi] With our scientific understanding of the microbiome still limited, what we don't know could hurt us. She said:
"These microbes are perhaps not the main drivers [of health] and may have more subtle roles in our biology, but it might be the case that one of these microbes does have a unique function and decreasing its levels may have significant health impacts."[vii]
More Chemical Exposures: Fewer Healthy Microbes
Children, especially toddlers, are more vulnerable to ingesting environmental toxins for many reasons, including closer proximity to carpets, dirt and dust, and a tendency to put toys and household items into their mouths.[viii]
Kids are also at greater risk from toxic exposure due to their smaller size, dietary habits and inability to modify their environment.[ix] It's up to adults to protect them, which begins with awareness of the causes and effects of chemical exposures.
Gardner hopes the study will prompt more research into diagnostic tools for detecting chemical exposures, as well as probiotic interventions to improve health outcomes.[x] "Gaining a more holistic understanding of the interactions between human-made chemicals, the gut microbiome, and human health is a critical step in advancing public health," she said.
Are Microbes the Key to Human Health?
The human microbiome refers to the collection of microbes, including bacteria, fungi, viruses, parasites and protozoa, living in and on the human body. It is estimated that there are 200 times more microbial genes in the human body than human genes.[xi] Not acknowledged by science until the 1990s, much of the functioning of the microbiome remains to be discovered.
Put simply, the microbiome is responsible for supporting human life. So far, science has credited the bacteria in our bodies with helping digest food, metabolizing vitamins and minerals, regulating the immune system and protecting the body from diseases caused by unhealthy microbes.
Many autoimmune diseases, such as rheumatoid arthritis and multiple sclerosis, are associated with dysfunction in the microbiome. You may even be the recipient of ancestral bacteria in the form of a microbiome inheritance that functions not unlike the passing of DNA from generation to generation.[xii]
Dietary support for the microbiome is one of the most powerful ways to please your microbes. Fruits, vegetables and seeds like flax and chia are excellent prebiotics that not only boost the immune system but also balance the microbiome. For more information about the microbiome, consult GreenMedInfo.com, the world's most widely referenced, evidence-based natural medical resource.
[i] 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
[ii] Washington State University. (2020, November 12). Connection between household chemicals and gut microbiome. ScienceDaily. www.sciencedaily.com/releases/2020/11/201112080906.htm
[iii] Washington State University. (2020, November 12). Connection between household chemicals and gut microbiome. ScienceDaily. www.sciencedaily.com/releases/2020/11/201112080906.htm
[iv] EPA.gov, Ground Water Issue: Reductive Dehalogenation of Organic Contaminants in Soils and Ground Water. https://www.epa.gov/sites/production/files/2015-06/documents/reductive_dehalo.pdf
[v] Washington State University. (2020, November 12). Connection between household chemicals and gut microbiome. ScienceDaily. www.sciencedaily.com/releases/2020/11/201112080906.htm
[vi] Washington State University. (2020, November 12). Connection between household chemicals and gut microbiome. ScienceDaily. www.sciencedaily.com/releases/2020/11/201112080906.htm
[vii] Washington State University. (2020, November 12). Connection between household chemicals and gut microbiome. ScienceDaily. www.sciencedaily.com/releases/2020/11/201112080906.htm
[x] Washington State University. (2020, November 12). Connection between household chemicals and gut microbiome. ScienceDaily. www.sciencedaily.com/releases/2020/11/201112080906.htm
[xi] University of Washington, Center for Ecogenetics & Environmental Health, Fast Facts About the Human Microbiome, https://depts.washington.edu/ceeh/downloads/FF_Microbiome.pdf
[xii] University of Washington, Center for Ecogenetics & Environmental Health, Fast Facts About the Human Microbiome, https://depts.washington.edu/ceeh/downloads/FF_Microbiome.pdf