"Preventing Ulcerative Colitis with Diet"
What has driven the dramatic increase
in prevalence of the inflammatory bowel disease,
Crohn's disease, in societies that are rapidly
westernized - a disease practically
unknown just a century ago?
What has truly changed in our
internal and external environment
that has led to the appearance
of this horrible disease?
Well, Japan suffered one of
the most dramatic increases,
and of all the changing dietary components,
animal protein appeared to be the strongest factor,
an exponential increase in
newly diagnosed Crohn's patients
and daily animal protein intake.
Whereas the more vegetable protein,
the fewer the cases of Crohn's,
which is consistent with data showing
a more plant-based diet may be successful
in both preventing Crohn's disease
and in treating Crohn's disease.
But what about inflammatory
bowel diseases in general?
The largest study of its kind,
60,000 people followed for over a decade
found that high total protein intake,
specifically animal protein, was associated
with a significantly increased risk of the other
big inflammatory bowel disease
as well, called ulcerative colitis.
Not just protein in general;
the association between high protein intake
and inflammatory bowel disease risk
was restricted to animal protein intake.
And since World War II,
animal protein intake has increased
not only in Japan but also
in all developed countries.
This increase in animal protein consumption
may explain some of the increased incidence
of Inflammatory Bowel Disease
in the second half of the 20th century.
And it's not just this study;
it's about what most other
studies found as well, but why?
What's the difference between
animal protein and plant protein?
Well, animal proteins tend to have more
sulfur containing amino acids like methionine,
which bacteria in our gut can turn into
the toxic rotten egg smell gas, hydrogen sulfide.
Emerging evidence suggests that sulfur compounds
may play a role in the development of ulcerative colitis,
this chronic inflammatory bowel disease
of the colon and rectum
characterized by bloody diarrhea.
The first hint as to the importance
of our gut flora in general was in the 1970s
when analysis of stools showed
that their bulk was made up of mostly
bacteria, not undigested material.
Most of our stool by weight is pure bacteria.
We're pushing out trillions of bacteria a day.
They just keep multiplying and multiplying.
And they do wonderful things for us
like create the protective compound butyrate
from the fiber we eat.
But it depends on what we feed them.
Bacteria may also elaborate toxic products
from food residues such as hydrogen sulfide
in response to a high-meat diet.
Hydrogen sulfide is a bacterially derived cell poison
that has been implicated in ulcerative colitis.
We had always assumed that sulfide generation
in the colon is driven by dietary components
such as sulfur-containing amino acids,
but we didn't know for sure, until this study.
They had folks eat five different diets
each with escalating meat contents
from vegetarian all the way up to like a steak a day.
And the more meat, the more sulfide;
10 times more meat meant 10 times more sulfide.
They conclude that dietary protein from meat
is an important substrate for sulfide generation
by bacteria in the human large intestine.
Hydrogen sulfide can then act as a free radical
and damage our DNA at concentrations way below
what our poor colon lining is exposed
to on a routine basis, which may help
explain why diets higher in meat and lower in fiber
may produce so-called "fecal water"
that causes about twice as much DNA damage.
Fecal water is like when researchers
make a tea from someone's stool.
The biology of sulfur in the human gut
has escaped serious attention until recently.
Previously it was just thought of as the rotten egg smell
in malodorous intestinal gas.
But the increase in sulfur compounds in response
to a supplement of animal protein
is not only of interest in the field of flatology,
which is the formal study of farts,
but may also be of importance
in the development of ulcerative colitis.