As we know from watching ads for probiotic yogurt on TV, stomach-resident microorganisms play a big part in how well we digest food, and how well we feel. Get the balance right, and you can feel like the woman putting strawberry flavor in her mouth, and grinning like sunshine. Get it wrong, and you’re bloated and irregular.
The gut is a complex place. Millions of good and bad bacteria compete for available nutrients, microbes help us to absorb vitamins, and the composition is constantly changing. Antibiotic drugs wipe out beneficial and non-beneficial bacteria indiscriminately, and what’s in our guts is affected by the types of food we eat, and other demographic and lifestyle factors.
Understanding the role of these variables is the key point of the American Gut Project, a citizen science project that has raised nearly $400,000 since last November, and gathered more than 4,000 volunteers so far. It has just completed its second round on Indiegogo, and will start another soon, hoping to reach 20,000 volunteers in all.
The idea is simple: in return for a donation that covers the cost of a self-sampling kit, you get a read-out of what’s in your personal microbiome. The kit is basically a glorified Q-tip that you use to take a small bit of stool. You fill in an extensive survey covering where you live, where you’ve traveled, and what’s in your diet (for example, what percentage of carbohydrate, fat, and protein you eat). Then you send in the sample, and wait for the results. The cheapest test costs $99, and allows you to compare yourself to people with similar, and dissimilar, lifestyles and eating habits. For more money, you can also test other parts of your body, such as the mouth and skin.
Jeff Leach, one of the leaders of the project, explains that research so far into microbiomes has been deep, but not wide. NIH funded the Human Microbiome Project to the tune of $173 million, but it studied only about 250 subjects. "They were all healthy people—average BMI, no diabetes, no high blood pressure—basically not the average American," he says. "We want anyone in America to sign up. It doesn’t matter if you’re a couch-potato or an ultra marathoner, vegan or vegetarian, we want the variability."
In fact, the project, which is based at the University of Colorado, is not limited to Americans, despite the name. About 10% of the volunteers so far have been out of country. And the researchers are not only interested in humans. They want samples from dogs, too. People’s gut may be affected by keeping pets, and the animals are certainly affected by the food they eat.
Leach, who has an anthropology background, hopes to use the American Gut data to study differences between humans from the developed world and less industrialized countries. This summer, he’s traveling to Tanzania to study the microbiomes of hunter-gatherers. "We’ll be able to compare people from America with people who are still foraging and don’t take antibiotics, eat McDonald’s, or drink tequila," he says.
Eventually, the aim is to help people understand not only what’s a healthy diet and lifestyle in a generalized sense, but what’s a healthy diet and lifestyle for them. Without a large group of citizens gathering online, answering that question would be a lot more difficult.