"Putrefying Protein and 'Toxifying' Enzymes"
Colon cancer is a leading cancer killer, yet there's this paradox in Africa
where they rarely get the disease even in modern times
when they are no longer eating their traditional whole food diet.
So they're no longer eating lots of fiber and fresh fruits and vegetables.
It is likely, therefore, that their continued low prevalence of colon cancer —
50 times lower than ours —
is related to their low intake of animal protein and fat
as I explored previously.
But why would animal protein and fat increase cancer risk?
Well, as I noted in Bowel Wars, if you eat egg whites, for example,
some of the protein isn't digested, isn't absorbed,
and ends up in our colon, where it undergoes
a process called putrefaction.
When animal protein putrefies in the gut, it can lead to the production
of the rotten egg gas, hydrogen sulfide, which, over and above
its objectionable odor, can produce changes that increase cancer risk.
Putrefying protein also produces ammonia.
Over a lifetime on a standard Western diet, the bacteria in our colon may
release the amount of ammonia found in a thousand gallons of Windex.
At concentrations found day-to-day inside the colon
on usual Western diets, ammonia destroys cells, alters DNA synthesis,
increases cellular proliferation, may increases virus infection,
favor the growth of cancerous cells, and evidently increase
virus infections a second time.
And it's the products of protein and fat digestion that are to blame,
such that you can double ammonia concentrations
in the colon by eating a lot of meat.
But put people on a plant-based diet, and within just one week
the enzyme activity that creates the ammonia in the colon drops like a rock.
Other bacterial enzymes are affected as well.
Remember how broccoli family vegetables
can boost detoxifying enzymes in the liver?
These so called phase 2 enzymes, UDP-glucuronosyltransferases,
they detoxify drugs and chemicals by applying a chemical straightjacket,
here shown in red, deactivating the date rape drug GHB,
or taking the carcinogens in meat like benzopyrene
and rendering them harmless before dumping them back
into the intestine for disposal.
But if our liver detoxifies it, why is benzopyrene in meat
still associated with rectal cancer?
Well, certain bacteria in our gut contain the opposite enzyme,
a 'toxifying' enzyme that removes the straightjacket
and frees the carcinogen to wreak
a last bit of havoc before it leaves the body.
But within one week of eating plant-based,
we can drop that enzyme activity in our colon by about 30%.
But this was with a raw, 'extreme' vegan diet.
What about a regular vegetarian diet?
Compared to a pound-of-meat-a-day diet, those placed on a meat-free diet
for a month experienced a 70% drop in 'toxifying' activity,
which may raise the amount of carcinogens, within the colon.
And long-time vegetarians exhibit just a fraction of carcinogen-releasing activity
compared to those on a standard American diet.
So this may all help explain the increased risk in the United States.
Researchers put it to the test, though,
by taking biopsies from the lining of the colons
of Americans versus Africans, to measure proliferation rates,
how fast the cells are dividing, a marker for increased cancer risk,
and decreased cancer survival.
This is what they found.
The black dots denote proliferating cells, which we can see throughout the colons
of Caucasian-Americans and African-Americans,
but only a few were seen in the African biopsies.
Dramatically lower proliferation rates.
Overall, higher colorectal cancer risk was associated with higher dietary intakes
of animal products and higher colonic populations
of potentially toxic hydrogen and secondary bile-salt-producing bacteria.
And while they were in there to get biopsies,
they looked around a little bit, and out of all the African colons they looked at,
they only detected four issues out of 18 colons.
But out of the 17 African American or Caucasian colons
they found 21 problems each: polyps, diverticulosis, lots of hemorrhoids.
The remarkably pristine condition of the colons of our African volunteers
further supports our impression that African colons were,
in general, far healthier than American colons.