The human gut is home to thousands of different bacterial species, totaling 100 trillion bacterial cells—that’s about four pounds of bacteria, or the weight of a brick. The composition of this bacterial population (also known as the gut microbiota), is currently being studied. Dr. Smith recently blogged on it.
A new study by researchers from the University of Pennsylvania, published in Science, takes the findings further. This new study found two major gut types—Bacteroides and Prevotella—based on gut bacterial population groups in 98 healthy volunteers who were asked to fill out questionnaires that assessed dietary habits. Stool samples were collected to determine their gut microbiota composition.
The researchers found a link between dietary habits and gut types. People who ate a diet high in meat and saturated fat were higher in Bacteroides bacteria, and people who had a diet high in carbohydrates had more Prevotella bacteria. Researchers then took ten volunteers and fed half of them a diet high in fat and low in fiber, and fed the other half a low-fat, high-fiber diet. By the end of ten days the bacterial populations had begun to change, but were still predominantly the same Bacteroides and Prevotella groups. This indicates that it’s possible to change the gut microbiota with diet, but it will take more than a short term change to see any major difference.
Next steps will be to replicate these findings to confirm them, and to take the studies further by looking at whether these gut types are associated with health or disease. It’s an exciting area of research, working out the details of what I have said all along—your gut is the foundation of the health of the rest of your body. It all begins in the gut.