Researchers in the American Gut Project who are studying microbe contents of human guts in the United States released their first report on September 17, 2013. Based on over 800 people, they can show how many are growing harmful organisms like E. coli as well as the beneficial microbe populations.
It turns out the two most common bacterial phyla in our guts are Firmicutes and Bacteroidetes. The proportions vary widely depending on diet. Paleo eaters who avoid grains, processed foods, and dairy have over 75 percent Firmicutes. Those with celiac disease on gluten-free diets have less than 50 percent Firmicutes. Further study determined that age makes a bigger difference than diet, exercise or sex, with babies having the most diverse intestinal microbes.
Regarding health, palio dieters have lower levels of Proteobacteria which are linked to inflammation, but more Firmicutes linked to high obesity rates. Proteobacteria also includes harmful species like E. coli and Salmonella. The conclusion is that it is going to take a more detailed analysis to understand the complexity.
Once concept that was verified is that taking antibiotics takes a toll on the digestive tract. One participant on antibiotics lost half of his Firmicutes. Even three weeks after finishing the antibiotics, he had not regained his previous balance. This validates the suggestion that antibiotic users should eat probiotics like yogurt to restore their gut populations.
View the list for the most important foods for a healthy digestive system.