The Story of the American Gut

As National Skilled Nursing Care Week winds down at Park Crescent, let’s add another story to all the narratives we’ve shared over the last few days. It’s the story of the American gut. The latest reports from The American Gut, part of an ongoing global microbiome project, tell us more about what’s going on inside our bodies. Our eating habits, lifestyle choices, and even mental health seem to have a direct relationship with our gut health.

What is the American Gut project?

Did you know that you have trillions of tiny organisms living inside you and on your skin? We are literally crawling with bacteria—billions and trillions of them. Most of the bacteria in the human biome are neutral or even beneficial. There’s a growing body of evidence that the makeup of the bacteria in our guts—or our gut microbiota—plays a significant role in our health.

The American Gut is a crowd-sourced project founded in 2012 by  Dr. Rob Knight, Dr. Jeff Leach, and Dr. Jack Gilbert. They call their project “citizen science,” where the general public can join in discovering and sharing scientific knowledge. Participants collect samples of their fecal, oral, and skin bacteria, and send them to the lab. They also answer a survey about their food and lifestyle choices, as well as their overall health. Participants cover the costs of processing, sequencing, and analyzing their samples.

Because of the diverse response to this project—15,000 samples from 45 countries in 3 years—the researchers collected a wealth of scientific information. The recent results offer some fascinating insight into how our guts function.

Result 1: Possible benefit to eating a diverse, plant-based diet

The sample analysis found that people who eat more than 30 different types of plant-based foods a week have more diverse bacteria than those who eat 10 or fewer types of plants. It’s important to maintain a rich and balanced bacterial makeup in our guts at all times. Without all the “good” bacteria to counteract the bad, we’re more likely to develop infections and inflammation. Those who ate a primarily plant-based diet also had fewer drug-resistant genes in their gut microbiomes. These findings tell us how important eating fruits, vegetables, and grains are. Besides for offering their own benefits, when you eat many different plant-based foods, you probably eat less meat and processed foods. Most meat today is full of antibiotics, as are processed foods. Consuming too much antibiotics will mess up the delicate balance in your gut.

Similarly, participants who took antibiotics within a month before giving their sample had less bacterial diversity in their gut than those who didn’t.

Result 2: Mental health linked to gut microbiome

The researchers analyzed the microbiomes of participants who reported having mental health problems. They compared each participant who reported mental illness to similar participants without any of these conditions. The findings showed that people with poor mental health are more closely related to each other—in terms of gut microbiota—than to their peers. It’s hard to tell which one caused the other, or if there’s any causality there at all. However, future research might shed light on this fascinating link between the gut and the brain.