The Effect of Roundup® on Human Gut Bacteria

Aria Eppinger discussing researchA childhood head injury left Aria Eppinger, Class of 2020, with painful memories—and the premise for her pioneering and prizewinning research into the effects of Roundup®, the world’s top-selling herbicide, on the human gut microbiome.

“I was inspired by science magazine articles showing correlations between head trauma and gut dysbiosis,” relays Eppinger, now a teenager and fully recovered. “I learned that gut dysbiosis is an imbalance in beneficial and harmful gut bacteria, and is associated with diseases such as diabetes and cancer.” Digging deeper, she discovered that food exposure to Roundup can cause gut dysbiosis in animals—and that no studies had been conducted on the effects of Roundup on the human gut microbiome.

“Roundup is the most common herbicide sprayed on genetically modified crops,” says Eppinger. “However, we are only beginning to understand the impact it may have on our health. The purpose of my experiment was to determine those effects.”

RAPID Lab gave her the space – and tools – to do it.

As a student in RAPID Lab, the Middle School STEM elective that empowers students to investigate scientific principles, create inventions, and design solutions to real-world problems, Eppinger enjoyed the freedom—and resources—to explore her idea for a full academic year. Headquartered in the Upper School research science lab, she devised a unique protocol to compare the growth pattern of beneficial and detrimental gut bacteria, and to measure the effect of glyphosate, the major active ingredient in Roundup, on that growth.

At the beginning of the year, Eppinger formulated serial dilutions of Roundup— “…different concentrations of Roundup in a 1:10 ratio created by putting 9mL of water with 1mL of Roundup”—repeating the process until she had glyphosate dilutions ranging from 2% to 0.0002%. Next, she used an incubator shaker to grow both kinds of bacteria and expose them to the dilutions. Growing the bacteria in a way that worked with her class schedule—thus allowing her to conduct the necessary trials—presented a challenge, which she surmounted by ‘MacGyvering’ available technology.

“Standard lab procedures for growing bacteria and measuring growth require OD (optical density) 600 measured every 10 minutes using a spectrophotometer for six hours,” explains Eppinger. “Since this was not realistic with my schedule, colorimeters were placed in an incubator to measure optical density. This allowed the bacteria to grow and be measured every 10 minutes for 12 hours without me being present.”

Finding that my data does support my hypothesis was really cool.

After months of work, it was awesome to see how it all added up to the conclusion I drew.

Aria Eppinger, Class of 2020

Finally, in the spring, Eppinger analyzed the data and ran statistical analysis, using both statistical software and LabQuest, a computer interface that collects, graphs, and analyzes data. The conclusion: Roundup exposure affected beneficial bacteria more than it did detrimental bacteria.

“Finding that my data does support my hypothesis was really cool,” enthuses Eppinger, who has long loved analyzing data and looking for patterns, whether in her artwork or in her favorite subject, math. “After months of work, it was awesome to see how it all added up to the conclusion I drew.”

An Award-Winning Project

Eppinger’s work not only shed light on Roundup’s effect on the human gut microbiome; it garnered several awards, winning first place in the Medicine, Health, and Microbiology category at the Pittsburgh Regional Science and Engineering Fair; Best Intermediate Project; and a Carnegie Science Award. Most prestigious of all, Eppinger was one of 30 finalists and an award winner at Broadcom MASTERS ( Math, Applied Science, Technology, and Engineering Rising Stars), a national STEM competition for middle school students. Her project earned the Robert Wood Johnson Foundation Award for Health Advancement, which honors the student who shows the most promise in health-related fields. But the budding biostatistician isn’t stopping there.

“I plan to hopefully publish my work in a journal of some kind. I also intend to further research the effects of Roundup, or glyphosate, on the gut microbiome, because Roundup’s effects are still not fully known.”

Aria winning award
Aria wins the Robert Wood Johnson Foundation Award for Health Advancement.

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