08/05/26

What do people eat? Plant and animal DNA in sewage provide clues

Imagine you wanted to get a general idea of what people are eating in a given community. You could look at grocery store sales, or do surveys, but neither can capture a complete picture.

Microbiome researcher Lawrence David and his lab look to another source of data: genetic material in sewage water. It turns out that detectable DNA signatures of individual plant and animal species remain behind even after they’ve been eaten, digested, excreted, and flushed down the toilet. He joins Host Flora Lichtman to describe his “Edible Atlas” project, the backend limitations of sewage analysis, and where the research might go.


Donate To Science Friday

Invest in quality science journalism by making a donation to Science Friday.

Donate

Segment Guests

Lawrence David

Dr. Lawrence David is an associate professor of molecular genetics and microbiology in the Center for Genomics and Computational Biology. He runs the Edible Atlas project at Duke University.

Segment Transcript

The transcript is being processed. It will be available 2-3 days after this story’s publication date.

Meet the Producers and Host

About Flora Lichtman

Flora Lichtman is a host of Science Friday. In a previous life, she lived on a research ship where apertivi were served on the top deck, hoisted there via pulley by the ship’s chef.

About Charles Bergquist

As Science Friday’s director and senior producer, Charles Bergquist channels the chaos of a live production studio into something sounding like a radio program. Favorite topics include planetary sciences, chemistry, materials, and shiny things with blinking lights.

Explore More