Wastewater surveillance gained prominence over the last few years for monitoring diseases, but researchers at Arizona State University (ASU) are now investigating the use of wastewater to better understand dietary trends that could be used to improve public health.
For seven consecutive days each month over a period of two years from 2017 to 2019, a team of ASU scientists collected daily samples from a sewer catchment serving less than 10,000 residents of Tempe, Arizona, to dive deep into the human gut microbiome.
In total, the team collected 156 samples and analyzed them with a focus on chemical and biological indicators of phytoestrogen consumption, common in plant-based diets and rich in foods like soy beans, lentils and sprouts.
“For example, at the beginning of each year during this study, we saw huge spikes in phytoestrogen levels that strongly suggest behavioral change along the lines of New Year’s resolutions to eat healthier foods,” announced Devin Bowes, who helped lead the study during her doctoral work in biological design at ASU.
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Phytoestrogen consumption was also slightly lower overall on weekends versus weekdays, according to the study, recently published in Nature.
People in the U.S. consume on average between one to three milligrams of phytoestrogens per day, but the study found that average consumption over the two years was four to five milligrams per day.
“That’s a big difference, so we wanted to dig deeper to find out why,” Bowes said.
Ultimately, the researchers determined that the Asian demographic in the study’s catchment area (about 25% of the local population compared to 5% nationwide) contributed to the phytoestrogen boost due to an increased intake of soy-based products common in many Asian diets.
Being able to gauge these dietary changes could be useful for places such as schools, Bowes said, where changes in lunch programs, for instance, could be evaluated in near real-time.
“They also could add other biomarkers that can indicate the presence of nutrition-related chronic diseases so health professionals could customize how they intervene,” Bowes explained.
Using liquid chromatography with tandem mass spectrometry, the ASU team was even able to detect surges in alcohol consumption during the St. Patrick’s Day holiday by measuring the alcohol metabolite ethyl sulfate.
Wastewater surveillance techniques can be used to assess many factors influencing community health, such as local diets, alcohol, illicit drugs and tobacco, and even exposure to hazardous chemicals, pharmaceuticals, personal care products, viruses and antibiotic-resistant microbes.
