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You Are What You Poop
Scientists have long studied waste, not the trash we throw out each week, but the waste that comes from our bodies and the bodies of animals. They’re studying fecal matter to understand better the nutrition we and other animals consume. It could also improve how we control diseases such as diabetes.
One interesting fact is that of earth’s 200,000-300,000 edible plants, humans have only consumed about 7,000. In a typical human, about 10 to 20 plant species and 4 animal species pass through our intestines at any time. Because digestion is an incomplete process, intact pieces of each species’ genome are left and become fecal matter or poop. There’s undigested food, billions of bacteria in our gut that aid digestion, and human cells discarded by our tissues and organs. DNA sequencing shows what and how much was eaten. It’s way more reliable than self-reported accounts since people tend to leave out the poor foods they eat.
One surprising result was that obese children had a higher diversity of plants in their stools. An explanation is that highly processed foods have more diverse ingredients. For example, they found that a Big Mac, fries, and coffee had 19 different plant species. Doctors gather fecal samples from their patients to diagnose disease, but this could also be a way to evaluate a person’s health. It would reveal their nutritional intake and maybe help control or prevent disease.
More Information
Poop Doesn't Lie: What Fecal 'Forensics' Tells Us About Diet
A lightbulb moment hit as Lawrence David was chatting one day with an ecologist who studies the microbiomes and diets of large herbivores in the African savanna. David was envious. He'd been studying the human microbiome, and this ecologist had tons of animal statistics that were way more specific than what David had obtained from people.
A study of the correlation between obesity and intestinal flora in school-age children
With the improvement of living standards and dietary changes, childhood obesity has increased worldwide. This study aimed to understand the differences of intestinal flora structure between obese and normal children at school-age.
Diversity of plant DNA in stool is linked to dietary quality, age, and household income
The past 30 y have seen repeated calls for innovation in dietary assessment of human populations, yet field standard methods in epidemiology all still rely on asking individuals to self-report their diet. We developed a scalable tool for assessment of dietary plant intake in free-living humans by sequencing plant DNA in stool.
