Change your diet.
From NPR, http://n.pr/JeWCh4, an excerpt:
Switching to a diet packed with meat and cheese — and very few carbohydrates — alters the trillions of microbes living in the gut, scientists report Wednesday [12/111/13] in the journal Nature.
The change happens quickly. Within two days, the types of microbes thriving in the gut shuffle around. And there are signs that some of these shifts might not be so good for your gut: One type of bacterium that flourishes under the meat-rich diet has been linked to inflammation and intestinal diseases in mice.
“I mean, I love meat,” says microbiologist Lawrence David, who contributed to the study and is now at Duke University.
[The researchers] wanted to know whether fiber — or lack of it — could alter gut bacteria more rapidly.
To figure that out, the researchers got nine volunteers to go on two extreme diets for five days each.
The first diet was all about meat and cheese. “Breakfast was eggs and bacon,” David says. “Lunch was ribs and briskets, and then for dinner, it was salami and prosciutto with an assortment of cheeses. The volunteers had pork rinds for snacks.”
Then, after a break, the nine volunteers began a second, fiber-rich diet at the other end of the spectrum: It all came from plants. “Breakfast was granola cereal,” David says. “For lunch, it was jasmine rice, cooked onions, tomatoes, squash, garlic, peas and lentils.” Dinner looked similar, and the volunteers could snack on bananas and mangoes.
“The animal-based diet is admittedly a little extreme,” he says. “But the plant-based diet is one you might find in a developing country.”
David and the team analyzed the volunteers’ microbiomes before, during and after each diet. And the effects of all that meat and cheese were immediately apparent.
“The relative abundance of various bacteria species looked like it shifted within a day after the food hit the gut,” David says. After the volunteers had spent about three days on each diet, the bacteria in the gut even started to change their behavior. “The kind of genes turned on in the microbes changed in both diets,” he says.
In particular, microbes that “love bile” — the Bilophila — started to dominate the volunteers’ guts during the animal-based diet. Bile helps the stomach digest fats. So people make more bile when their diet is rich in meat and dairy fats.
A study last year found that blooms of Bilophila cause inflammation and colitis in mice. “But we didn’t measure levels of inflammation in our subjects,” David says. “That’s the next step.”