Wastewater reveals the diets of entire communities – Earth.com
07-21-2026
Wastewater reveals what entire communities are really eating
ByAndrei Ionescu
Earth.com staff writer
Community wastewater is turning out to be an unlikelyentire neighborhoods are eating without relying on surveys or food diaries
A recent study analyzed DNA fragments from sewage across North Carolina and found that what shows up in the drain closely tracks with income, immigration patterns, and geography
The study was led by researchers at Duke University School of Medicine and the University of North Carolina at Chapel Hill.
The team analyzed wastewater samples from 19 North Carolina communities representing 2.1 million people, extracting tiny fragments of plant and animal DNA to reconstruct broad dietary patterns across each population
Beer, fruit, and fish tell different stories
The patterns that emerged tracked closely with demographic and economic differences between communities.
Wealthier neighborhoods were more likely to show traces of hops, a key ingredient in beer. Areas with larger foreign-born populations revealed evidence of tropical fruit and bean consumption
Along the coast, wastewater carried clear signatures of seafood-heavy diets, including locally caught species like drum, Spanish mackerel, and triggerfish
“Poor diet is one of the world’s biggest drivers of chronic disease, but we’ve never had a fast objective way to measure what people eat,” said senior author Lawrence A. David, a member of the Duke Microbiome Center.
“This study helps fill that gap so we can better connect diet to health.”
A gap in nutrition research
For decades, nutrition researchers have relied on food diaries and surveys to track what people eat. Such methods that are notoriously expensive, time-consuming, and unreliable.
People forget what they ate, underreport unhealthy choices, or simply never get surveyed in the first place.
In addition, the communities most affected by diet-related disease are often exactly the ones hardest to measure using these traditional tools
To get around those limitations, Duke researchers developed FoodSeq-FLOW, a DNA-sequencing platform designed to mine wastewater for clues about what communities are actually eating and preparing.
Lead study author Mengyi Dong led the genomic analysis while at Duke, translating raw DNA sequences into identifiable plant and animal species
COVID-era wastewater tracking
The approach builds directly on wastewater surveillance infrastructure that expanded rapidly during COVID-19
Virus fragments shed in human waste helped public health officials detect and track outbreaks in real time.
That same infrastructure is now used to monitor a range of infectious and respiratory diseases, and researchers are pushing it further still, beyond disease detection entirely
Using their new sequencing platform, the team analyzed wastewater samples collected from eight treatment plants across three North Carolina regions during two separate study periods spanning June through December 2020 and June 2021
“Wastewater offers an objective way to monitor dietary patterns across entire communities and could help guide more targeted nutrition and food security programs,” said Dong, now an associate professor at Virginia Tech’s Seafood Agricultural Research and Extension Center
“Food security isn’t just about whether enough food is available. It’s also about ensuring communities can access healthy, nutritious options.”
A tool with real-world applications
The potential applications are already drawing interest from local communities.
In Durham’s historic Hayti neighborhood, local leaders are working to bring in a Black-owned full-service grocery store
They see this kind of data as a way to demonstrate the measurable impact such a store could have in an area that’s been described as a food desert
“It would allow us to eat healthier foods more regularly because we wouldn’t have to travel so far to get them,” said Erin Dooley, co-founder of BLK South and resident of the Grant Street Community.
“What’s unique about Dr. David’s research is that it’s not just hard facts and data, but it supports our lived experiences.”
Validating the method
To confirm the wastewater data was actually reliable, researchers compared the DNA patterns they found against dietary data from 14 stool samples collected in Durham in June 2021.
The two data accurately reflect local diets rather than just offering a rough approximation
Importantly, the researchers emphasize that the goal isn’t to monitor individuals, but to measure broad community-level patterns instead.
“The result is a snapshot of the community that helps understand where ref marine sciences at UNC-Chapel Hill
Implications for local food communities
Noble notes that the DNA markers developed at Duke can identify food
For example, the data showed that inland communities rely heavily on just a handful of seafood varieties, particularly farmed fish like Atlantic salmon, rather than drawing on the broader range of local or regional options available elsewhere in the state
“Could we be doing more to support local fisheries and make their seafood more available? It looks like we certainly could,” Noble concluded
The study is published in the journal Proceedings of the National Academy of Sciences
—-
Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates
Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com
——
