How to Change Your Enterotype


“How to Change Your Enterotype” If whatever gut flora enterotype we are
could play an important role in our risk of developing chronic diet-associated
diseases, the next question is can we alter our gut microbiom
by altering our diet? And the answer is diet can rapidly and
reproducibly alter the bacteria in our gut. There’s been growing concern
that recent lifestyle innovations, most notably the high-fat/high-sugar
‘Western’ diet, have altered the composition and activity of our resident gut flora. Such diet-induced changes to gut-
associated microbial communities are now suspected of contributing to
growing epidemics of chronic disease in the developed world,
yet it remained unclear how quickly our gut bacteria
could respond to dietary change. So they prepared two diets:
a ‘plant-based diet’ rich in grains, beans, fruits and vegetables; and an ‘animal-based diet’ which was
composed of meats, eggs, and cheeses. Note no refined sugars in either—they
just wanted to test plant versus animal. And within just one day of the
animal-based diet hitting the gut, there was a significant shift. For
example, the lifelong vegetarian. What happens when you put
him on an animal-based diet? Well, he started out Prevotella, like
the one vegan in the typing study, but unlike everyone else, because they were
eating a more standard American diet. Remarkably, the animal-based
diet inverted the vegetarian’s Prevotella to Bacteroides ratio, causing the Bacteroides to
outnumber the Prevotella within just four days on
an animal-based diet. His entire gut flora got
turned on its head. The fact that our gut can so rapidly switch
between herbivorous and carnivorous functional profiles is probably
a good thing evolution-wise. I mean, if you bring down a mammoth
and you’re eating meat for a couple days before falling back to plants, you
want your gut to be able to deal, and this flexibility is manifest in the
diversity of human diets to this day, but what’s the healthier state
to be in most of the time? They looked at a number
of different factors. First, the amount of short chain
fatty acids produced. Short-chain fatty acids like acetate, butyrate,
function to suppress inflammation, suppress cancer, and our gut flora
on plant-based diets produced more than on animal-based diets. Other microbial metabolites,
such as secondary bile acids, promote the development of cancer,
and with a significant increase in bacterial enzyme activity to create
these secondary bile acids on an animal-based diet, no surprise:
significant increase in carcinogens like DCA, a secondary bile acid known to promote
DNA damage and liver cancer. Microbial enzyme activity to produce
the rotten egg gas hydrogen sulfide also shoots up on an animal-based diet,
which stinks because it… stinks, and because it damages DNA, and has
been implicated in the development of inflammatory bowel diseases
like ulcerative colitis. Hydrogen sulfide is made by pathogens
like Bilophila wadsworthia, which is increased on the animal-
based diet, again within just days, supporting the link between diet and
the outgrowth of microorganisms capable of triggering
inflammatory bowel disease. Whereas the only pathogen you
see more of on a plant-based diet is just a virus
that infects spinach.