A new technique using DNA barcoding to identify the plant matter in human feces may get at the truth, improving clinical trials, nutrition studies, and more.
Building on earlier studies that attempted to compare DNA found in feces with reported diets, researchers in the lab of MGM's Lawrence David have developed a genetic marker for plant-based foods that can be retrieved from poop.
The marker is a region of DNA plants use to power chloroplasts, the organelle that converts sunlight into sugars. Every plant has this genomic region, called trnL-P6, but it varies slightly from species to species. In a series of experiments, they tested the marker on more than 1,000 fecal samples from 324 study participants across five different studies, about twenty of whom had high-quality records of their diet.
In findings in the Proceedings of the National Academy of Sciences, the researchers show that these DNA markers can indicate not only what was consumed, but the relative amounts of certain food species, and that the diversity of plant DNA found in feces varies according to a person’s diet, age, and household income.
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