Leaky gut, microbiome, autoimmunity, and the diseases associated with
these terms are coming into relatively common usage.
Few people who use them, however, really know their meaning, how
they are related, and how they influence disease, its prevention, and
A biome is simply any natural community of plants and animals
that occupy some major area like a forest, for example.
It seems to have been coined in 1916 by an American ecologist
named Frederic Clements.
Joshua Lederberg is thought to be the first to use the term microbiome
The word biome comes from two Greek forms: bios meaning life, and -oma,
which is a kind of neutral, neuter, word-forming suffix that indicates
an entity of some kind.
Western medicine has co-opted this suffix to refer to various kinds of
tumor like carcinoma.
Microbiome has come into greater use since about 2008 with the start of
the Human Microbiome Project of our National Institutes of Health.
The purpose of this project is to explore the communities of
human cells and microorganisms that live throughout your body, and how
they affect your health.
These communities exist in various places like your lungs and skin, but
most interest has been shown in the microbiome residing in your gut.
What is your gut?
Often called the gastrointestinal tract, GI tract, or alimentary canal,
your gut consists of all the organs and structures you use to take in
food, digest it, and eliminate the waste products.
That is, your gut includes your mouth, esophagus, stomach, small
and large intestines, and anus as well as your pancreas, liver,
gallbladder, and more.
The processing of food, digestion, is amazingly complex.
It involves not only the precisely controlled release and
absorption of a myriad of chemicals, but also continuous two-way
communication between your gut and your brain.
Some suggest that your gut is really a second brain.
What is a leaky gut?
The wall of the small intestine part of your gut may seem impenetrable,
but it is, in fact, selectively permeable.
That is, its job is to let through the wall nutrients and other
beneficial substances so they can be distributed through your blood to
the parts of your body that need them.
At the same time, it needs to keep out of your bloodstream some
bacteria and the toxins they produce as well as undigested bits of fats
The way it works is that the lining of your intestine, your immune
system’s first line of defense, consists of cells (epithelial cells)
that are connected to each other by what are called tight junctions.
On the surface of these cells are many tiny projections called
microvilli. Their work is to
absorb properly digested nutrients, and carry them through the cells
into your bloodstream.
During normal digestion, the tight junctions remain tight, blocking out
any substance that can’t be absorbed by the microvilli.
Leaky gut means that the tight junctions loosen up so those
larger bits of undigested food can get through into your blood along
with yeasts and other waste.
The next line of defense is your liver.
In response to the presence of these strange, foreign bodies in
your blood, your liver goes into overdrive trying to screen out the
particles your intestine wall was supposed to deal with.
However, no matter how hard it tries, your liver can’t keep up
with the constant influx of waste, which begins to build up in your
Now the big guns, your immune system, come on to get these intruders out
of your body. In general,
the job is too big for your immune system as well, and the foreigners
get absorbed into tissues throughout your body, causing them to become
inflamed. Inflammation is
also part of your natural immune response.
As this war escalates, other natural processes such as fighting off
bacteria, filtering your blood, and regulating your gut tend to be
ignored. The result is your
body fighting itself, which is the meaning of autoimmunity.
That is, your body is now producing extra antibodies that wind up
responding even to chemicals found normally in your food.
It’s easy to see how such conditions can lead to irritable bowel
syndrome, chronic fatigue, and other autoimmune diseases.
What loosens tight junctions?
There is controversy over the causes of leaky gut, but one commonly
accepted probable cause is intestinal inflammation.
Whether it’s inflammation because of low stomach acid letting
through undigested food or the influx environmental toxins, your tight
junctions may be loosened.
In addition, if the mutually beneficial normal balance of yeasts,
bacteria, viruses, and other organisms is disturbed, then your gut may
be compromised as well.
I have more to say about inflammation in my column from June 2.
If inflammation is chronic, you need to remove the cause.
Diet is commonly cited as causative as well.
Inflammation is associated with diets that are high in refined
sugars and processed foods, for example.
In addition, the casein in cow dairy and gluten in refined flour
products are known to be inflammatory.
Chronic stress tends to suppress your immune system, leaving it unable
to do its job normally. It
gets overburdened by pathogens easily, which leads to inflammation of
your gut, and loosening of those tight junctions.
Medications may be complicit as well.
Not only prescription medications, but over-the-counter drugs
containing acetominophen or aspirin can irritate the intestinal lining
and loosen tight junctions.
How to prevent (or fix) a leaky gut
There are four parts to a program that help to keep leaky gut under
control: diet, supplements, probiotics, and some digestive enzymes.
First, and perhaps most important, is to get off sugars, starches,
grains, soy, caffeine, and cow dairy.
Eliminating these inflammatory foods will not only reduce
intestinal irritation, but will also starve any yeast that has taken
over your intestines. A good
diet to consider for these purposes is the Specific Carbohydrate Diet.
I emphasize avoiding cow dairy because it is very high in the
troublesome casein. Sheep
dairy is better, and goat is the best.
These days, incidentally, farmers have learned how to make goat
dairy taste hardly at all goaty.
Second, consider increasing your nutritional supplements.
One problem with leaky gut is that your body is not making good
use of the nutrients you give it.
Fish oils, a multi-vitamin, vitamin D, and zinc are among the
more important supplements to try.
Next, you need to repopulate your gut with good bacteria like
lactobacillus acidophilus using a probiotic.
Fourth, you might wish to add some digestive enzymes to your diet.
Enzymes are chemical compounds that help chemical reactions to
occur. Lipases, for example,
are enzymes that enable the breakdown of fats, and proteases help to
breakdown proteins. There
are enzyme supplements, but there are foods as well that provide enzyme
support. These include
things like pineapple, grapes, avocado, coconut and extra-virgin olive
oil, and raw honey.
What should you do
There are some people who seem to be able to eat as much of anything as
they like, and have no unpleasant side effects.
If you are one of those, then God bless you!
However, I urge you to pay attention.
If you begin to have some of these symptoms chronically then
consider the possibility that your gut may be in trouble: fatigue,
trouble digesting what you eat, pain in your joints, difficulty
sleeping, depression, chronic diarrhea or constipation, intestinal gas,
or feeling bloated. You may
also think your immune system isn’t up to snuff, you may have rashes,
excessive craving for sweets and other carbohydrates, and even some
memory problems. Certainly
rheumatoid arthritis, Crohn’s, lupus, and other autoimmune diseases are
indicators of likely leaky gut.
In the meantime, bon appetite.