Originally posted by Dr. Davis on 2014-07-02
on the Wheat Belly Blog,
sourced from and currently found at: Infinite Health Blog.
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the garden called “bowel flora”
I like to think of bowel flora, the thousand or
so species of microorganisms that inhabit the human gastrointestinal
tract, as a garden. Probiotics, i.e., anything that
provides microorganisms believed to be among the desired inhabitants
such as the various Lactobacillus or Bifidobacteria species, are like
planting seeds for peppers and zucchini in your garden in spring time.
But what if you planted your seeds, then
neglected to water and fertilize your garden? If you’re lucky, you
might have a few peppers and zucchini after a few weeks, but you’re
more likely to have a few stunted vegetables or nothing except a few
shriveled vines. A successful garden requires water and fertilizer.
So it goes with bowel flora. You eliminate the
extraordinary bowel-disruptive effects of grains–gliadin,
gliadin-derived peptides, wheat germ agglutinin, indigestible D-amino
acids, trypsin inhibitors, and others–then “plant” some
desired species from a probiotic preparation or fermented food, but then
fail to nourish them. It means that desired species may not
proliferate, they may not outnumber and overpower unhealthy species such
as E. coli, Staphylococcus aureus, Clostridium
difficile, and Firmicutes. Unhealthy species are allowed to
proliferate, thereby increasing intestinal permeability and resulting
in higher blood levels of the bacterial byproduct, lipopolysaccharide,
that is highly inflammatory. It also means that healthy bacteria fail to
produce fatty acids, especially propionate and butyrate, that are
required by intestinal cells for normal metabolism, heal “tight
junctions” between cells (disrupted in conditions such as ulcerative
colitis), and reduce potential for colon cancer. It also means that
metabolic benefits, such as reduced insulin and blood sugar levels,
reduced triglycerides, reduced blood pressure, and reduced visceral fat
do not result–all because desirable bowel flora were not “fertilized.”
So what acts as water and fertilizer to bowel flora?
What feeds them, allows them to proliferate and yield factors such as butyrate?
Fibers. But not all fibers.
In a fascinating tale of symbiosis, the coexistence
of microorganisms and Homo sapiens, a specific class of fibers,
i.e., polysaccharides or polymeric sugars, that are indigestible to the
human digestive apparatus but digestible via the enzymes expressed by
specific bacterial species, allow all these beneficial health effects to
occur. It means that food, chewed, swallowed, bathed in stomach acid,
emulsified by bile, broken down into constituents by pancreatic enzymes,
exposed to 20-some feet of small intestine, finally reaching the colon
where most microorganisms dwell, contains little remaining nutrients to
nourish bacteria. The desirable species that thrive in this unique
environment are those that can digest the undigested remains of your
meal–fibers. But not cellulose fibers, i.e., wood fiber,
of the sort that dominates in grains and is found in bran cereals.
Cellulose is essentially indigestible by both our own digestive apparatus,
as well as the bacteria that humans are capable of carrying. (It is
digestible by ruminants.)
The proper care and feeding of bowel flora therefore
causes proliferation of healthy Bacterioidetes, Lactobacillus, and
Bifidobacteria that produce bacteriocins that suppress growth of unhealthy
species, metabolize fibers to butyrate that yields metabolic benefits,
even improves bowel habits and allows you to have normal, healthy bowel
movements without “crutches” like the bulk of cellulose
fibers, laxatives, or enemas.
Is this evolutionarily appropriate? Is there precedent
in human adaptation on this planet for such unique fibers? I ask this
question because this is my litmus test for the suitability of any dietary
strategy we consider. Recall, for instance, that grains were added 300
generations ago, or 0.4% of our time on earth, a mere moment in time ago.
They are inappropriate for human consumption, now made worse by the genetic
fiddlings of agribusiness. (I have to concede that grains do indeed
have some fibers that have health benefits, such as arabinoxylan in wheat
and beta glucan in oats, but they come with such undesirable other
components that it is simply not worth it.) Yes, consuming such
fibers is evolutionarily appropriate, as it dates back well over
8000 generations of human existence, predating even the appearance of the
Homo species, even predating carnivory, as it was practiced by pre-Homo
hominids, Australopithecus (especially “robust” strains). It
is therefore deeply instilled (I almost said
“ingrained”–acchhh!) into the adaptive physiology of our species.
So how do we obtain such indigestible fibers that
nourish healthy bowel flora, so-called “prebiotics” or
“resistant starches”? Well, do what a member of the Hadza
of sub-Saharan Africa or Yanomamo of the Brazilian rainforest would do
and grab a stick, stone, or bone fragment and dig in a field or forest
for the underground tubers of plants. If you don’t want to do that,
you can incorporate foods available in modern grocery stores that mimic
such practices. Among the foods that yield such fibers:
- Green unripe bananas or plantains–with around 27 grams
prebiotic fibers per medium sized banana
- Raw peeled potato–with around 20 grams per 3½ inch medium
- Inulin powder–with 5 grams per teaspoon
- Bob’s Red Mill raw unmodified potato starch–8 grams per tablespoon
- Legumes, lentils, chickpeas, hummus–Around 3 grams per ¼-cup.
But we have to be careful here, as any more than this quantity and blood
sugars start to climb to unhealthy levels.
(Thanks, by the way, to Richard Nikoley, the
prolific blogger of the Free the
Animal blog, who has done a spectacular job of providing meaningful
discussions around the science behind resistant starches, as well as
identifying the Bob’s Red Mill product as a convenient and available source.)
These are the most efficient sources, with lesser
quantities in other below-ground vegetables. I pick one of the above
foods and include them in a smoothie every morning along with, for instance,
a cup of unsweetened coconut milk, some blueberries or other berries, a few
drops of stevia, etc. If you choose the banana, peel it like an apple or
chop off the ends and slit the skin, as it is very tough to skin when green.
Chop both banana and potato coarsely before putting in the blender; a blender
with a strong motor is advised.
The science that examines bowel flora composition
tells us that 20 grams of such fibers yield substantial effects. While
the average grain-consuming human obtains around 3 or 4 grams per day,
us grain-deniers can fall below this and experience undesirable bowel and
metabolic effects. Benefits begin around 8 or 9 grams per day, with
maximal benefit likely around 20 grams. (Interestingly, there is
anthropological evidence of intakes as high as 135 grams per day.)
When new to this experience, start with no more than 10 grams fiber
per day; more and abdominal pain and bloating can occur; build up over days
to weeks. Full benefits, such as reductions in blood pressure and blood sugar,
require 4 to 8 weeks to show themselves, likely due to the shifts in
bowel flora species.
Every once in a while, a new strategy declares
itself that yields unexpected outsize benefits. Vitamin D was that
way, as well as wheat elimination. Now add restoration and management of
healthy bowel flora with probiotic and prebiotic strategies to that list,
strategies that acquire even greater importance in the grain-free lifestyle.