"Preventing Inflammatory Bowel Disease with Diet"
If you go online and search for Crohn's disease and diet,
or ulcerative colitis and diet, the top results are a hodgepodge
of conflicting advice. What does the science say?
If you do a systematic review of the medical literature on dietary
intake and the risk of developing inflammatory bowel disease,
Crohn's disease is associated with the intake of fat and meat,
whereas dietary fiber and fruits appear protective.
The same foods are associated with the other major inflammatory
bowel disease, ulcerative colitis: fat and meat,
with a protective association found for vegetable intake.
Why—according to this meta-analysis of nine separate studies—
do meat consumers have about a 50% greater risk
for inflammatory bowel disease?
Well, one possibility is that meat may be a vehicle for bacteria
that play a role in the development of such diseases.
Meat contains huge amounts of Yersinia, for example.
Yes, maybe antibiotic residues in the meat could be
theoretically kind of mucking with our microbiome,
but Yersinia are so-called psychrotrophic bacteria,
meaning they're able to grow at fridge temperatures.
It has been found to be significantly associated with inflammatory bowel
disease, supporting this concept that Yersinia infection
may be a trigger for chronic inflammatory bowel disease.
One reason why specifically animal protein was associated
with triple the risk of inflammatory bowel disease—
but plant protein was not— is because it can lead
to the formation of toxic bacterial end products,
such as the rotten egg gas, hydrogen sulfide,
which is not just one of the main malodorous compounds in human
flatus; it's a poison that has been implicated in ulcerative colitis.
So go on some meat-heavy, low-carb diet
and we're not just talking about some malodorous rectal flatus,
but increased risk of irritable bowel, inflammatory bowel syndrome,
and eventually colorectal cancer.
Hydrogen sulfide in the colon comes from sulphur-containing amino acids
like methionine that are concentrated in animal proteins,
though there are also sulfites added as preservatives
to some nonorganic wine and nonorganic dried fruit.
But it's the sulphur-containing amino acids that may be the more
important of the two. Give people increasing quantities of meat,
and you can get an exponential rise in fecal sulfides.
Specific bacteria, like Biophilia wadsworthia, can take this sulfur
that ends up in our colon and produce hydrogen sulfide.
And give people an animal product- based diet packed with meat
and eggs and dairy, and you can specifically increase
the growth of this bacteria. People underestimate the dramatic effect
diet can have on our gut bacteria.
Give people a fecal transplant and it can take three days
to shift your microbiome.
Take a powerful antibiotic like Cipro and it can take a week.
But start packing in the meat and eggs, and within a single day
you can change your microbiome— and not for the better.
You can more than double the bad bacterial machinery
that churns out hydrogen sulfide, consistent with the thinking
that diet-induced changes to the gut flora may contribute
to the development of inflammatory bowel disease.
In other words, the increase in sulfur compounds in the colon
when you eat meat is not only of interest in the field of flatology:
the study of human farts.