Welcome back. I'm Chandler. In this lesson, we're going to take a deep dive in understanding how
our digestive system works. Our digestive system is responsible for breaking down our food,
absorbing it, and helping to disseminate those nutrients throughout the body. My goal is that
by the end of this lesson, you'll not only understand how the digestive system works,
but have a basic understanding that if we work to support it and work with it,
we can give our bodies what it needs to complete its many functions. To start,
we know that we have a digestive system. Our digestive system is comprised of many organs
working together to break down, digest, and assimilate the nutrients in our food to fuel
everything in our body. Food digestion starts in our mouth through chewing and the secretion
of saliva that begins to break down our food. Food then travels down our esophagus to our
stomach where digestion continues through stomach acid and the churning motion of our stomach. If
you don't have enough stomach acid, you can't digest food properly or absorb its nutrients.
This can lead to indigestion, malnutrition, and sometimes even bacterial overgrowth. Your
stomach will hold the food until it's ready to go into the small intestine. Our small intestine is
where the bulk of our digestion and assimilation of our nutrients occur. As food enters the small
intestine, it mixes with digestive juices from your liver and your pancreas. Your intestinal
wall absorbs nutrients and the water from food and then sends waste products to the large intestine.
So let's take a closer look at the accessory organs to our digestive system now. So as food
enters the small intestine, like I said, the food is going to mix with digestive juices that help to
further break down and digest what is consumed. Your liver works around the clock to keep you
healthy. It has many roles, not only in digestion, but in detoxification for the body as well. Among
its many roles, it produces bile, which is stored in the gallbladder. This is a chemical that helps
turn fats into energy that your body uses. Bile is necessary for the digestive process. The liver
helps your body maintain a healthy level of blood sugar. Your liver supplies glucose, otherwise known
as sugar, to your blood when it's needed. It also removes glucose from your blood when there's too
much. In addition to aiding in digestion, your liver does a few other things that I believe are
really important to note. First, your liver creates albumin. This is a blood protein that
helps carry hormones, drugs, and fatty acids throughout your body. Next, your liver helps
your body get rid of bilirubin. Bilirubin is created through the breakdown of your red blood
cells. Too much bilirubin in the body can cause jaundice. This is when somebody might have the
yellowing of the skin and the eyes. Next, your liver is responsible for filtering toxins. When
you take in a potentially toxic substance like alcohol or medicine, for example, your liver
helps alter it and remove it from the body. Lastly, your liver controls immune response. So
when bacteria, viruses, and other harmful organisms enter your body, your liver can find and destroy
them. This is done by specialized cells in your liver. Next, we have your pancreas. Your pancreas
is another accessory organ to digestion that I want to make sure to highlight. It is located
inside your abdomen, just behind your stomach, and is about the size of your hand. During digestion,
your pancreas makes pancreatic juices called enzymes. These enzymes help to break down sugars,
fats, and starches. Your pancreas also helps your digestive system by making hormones,
which regulate your blood sugar, regulate your appetite, stimulate stomach acids, and tell your
stomach when they need to empty. The pancreatic enzymes that are secreted are three things. First,
we have lipase. This enzyme works together with bile, which your liver produces to break down
fat in your diet. If you don't have enough lipase, your body will have trouble absorbing fat and the
important fat-soluble vitamins, vitamins A, D, E, and K. Protease is your next enzyme. This
enzyme breaks down proteins in your diet. It also helps protect from germs that may be living in
your intestines, like certain bacteria and yeast. Undigested proteins can cause allergic reactions
in some individuals.
Lastly, you're going to have amylase. This enzyme help breaks down starches into sugar,
which your body can then use for energy. If you don't have enough amylase,
you may get things like diarrhea from undigested carbohydrates.
In addition to making enzymes that are released into your digestive system to aid in the digestion
of food, your pancreas releases hormones into the blood that carry messages to other parts
of your body and parts of your digestive system. These pancreatic hormones include insulin.
Insulin is the hormone that helps your body use sugars for energy. Without enough insulin,
your sugar levels rise in your blood and you can develop things like diabetes.
Glucagon is the next thing. If your blood sugar gets too low,
glucagon helps raise it by sending a message to your liver to release stored sugar.
Lastly, you have gastrin and amylin. Gastrin is primarily made in the G cells in the stomach,
but some is made in the pancreas too. It stimulates your stomach to make gastric acid.
Amylin is made in the beta cells and helps control appetite and stomach emptying.
Now that you have a basic understanding of what the accessory organs do to our
digestive system, let's look inside our small intestine to understand what is going on.
Once food passes into the small intestine, organisms that live in the GI tract help to
digest our food further. Our intestine is structured as follows. Our intestinal lining
has folds called villi that have deep crypts between them. These villi are lined with cells
called enterocytes that are responsible for digesting and absorbing nutrients from your
food. These enterocyte cells need to be young and healthy to do their job.
If you look in the middle image, you can see what a fold in the intestinal lining looks like.
To the right of that, you can see that the villi have these deep crypts within them.
And to the very right, you can see an enterocyte that lines the villi. The way it works is that
the youngest enterocytes are at the base of the villi, and as they age, they travel to the top
where they eventually die off and fall off, and the process will continue over again.
On the surface of the enterocytes and the villi, you have a layer of beneficial bacteria living
right on top, which you can see on the image to the left. When everything is in balance,
this bacteria not only helps keep the opportunistic or bad bacteria in check,
but the bacteria also provides 60-70% of the energy needed to the gut lining.
When this microbiome is disrupted and bacteria is not in the proper balance,
then the bad bacteria can overgrow and things can happen like leaky gut or increased intestinal
permeability, which is a condition that creates gaps in the linings of the intestinal walls.
These gaps then allow things like food particles, bacteria, and waste products
to seep directly into your bloodstream. Think of it like this. With a bacterial
layer over our cells and villi, which you can see on the left, there is a thick layer of turf
on the surface of the gut, which provides a protective layer against potential invaders
like bacteria, yeast, parasites, and viruses. What you see on the right is an image of what
happens when we have increased intestinal permeability, otherwise known as leaky gut.
You can see in this image that the bad bacteria are at a higher percentage than the good bacteria,
which slowly degrades the gut lining, allowing for increased permeability and for things like
undigested food, viruses, toxins, and other things to leak straight through and go into
your bloodstream, which can then lead to disease and other issues around the body.
So now that I have explained that there needs to be a good balance between good and bad bacteria
in the gut, I want to explain a little further what type of bacteria we have in our gut and
the role of that bacteria. There are actually three types of bacteria that you can find in
your gut. First is your essential flora. These we need in large, large quantities to keep everything
else in check. So you want to think of these kind of like your little soldiers in your gut.
Next we have opportunistic flora. Opportunistic flora is found in our gut and when kept in check,
doesn't cause any issues. However, when there is an overgrowth of this type of bacteria,
they can wreak havoc on our overall gut health and our immune system. Lastly,
we have transitional flora. These are gram negative bacilli that are actually found in
and when our gut ecosystem is in check,
no issues will arise.
I wanna highlight what our beneficial
or essential flora actually does for the body.
This flora is considered beneficial
because it keeps the pH of the gut to four to five,
making it a very uncomfortable living environment
for the bad bacteria.
This bacteria actually works synergistically
with our bodies to help digest the food we eat,
and then it actually helps deliver 60 to 70%
of the energy we need to our gut lining.
So now that we have looked at what our gut does,
I want us to take a look at some examples
of digestion occurring in a correct way in a healthy gut.
Let's look at the digestion of milk and wheat proteins,
since these are two very common offenders for people today.
The digestion of milk and wheat happen actually
in two stages.
The first stage occurs in the stomach,
where the stomach juices split the proteins into peptides.
Different peptides can have different structures
actually when they're broken down.
Some of these peptides can actually have things
like morphine-like structures to them.
These peptides then move to the second stage of digestion,
which occurs in our small intestine,
where they mix with pancreatic juices secreted
from the pancreas into the small intestine
and work to break down them even further.
When they reach the intestinal wall,
they're broken down by enzymes called peptidases
on the microvilli of your enterocytes.
So in a normal healthy person,
this can all occur without any hiccups.
When people have gut dysbiosis or leaky gut,
or a decreased ability to secrete stomach acid,
pancreatic juices, or they don't even have
enough good bacteria in their gut to help this digestion,
these morphine-like peptides are absorbed
straight into the bloodstream
because of those gaps in the gut lining.
This can then interfere with brain function
and the overall immune function of your body.
So as you can see, when our gut microbiome
isn't functioning correctly due to leaky gut
and improper balance of good and bad gut bacteria,
food isn't gonna properly be digested
and can cause things like allergies
and even lead to disease.
So to wrap up, I wanna quickly look at
how this all plays a role in the immune system.
Our lymphatic system, which is part of our immune system,
is located all throughout the body,
including in our intestinal wall.
This lymphatic tissue in our gut
has a large amount of lymphocytes,
which produce immunoglobulins,
one of the biggest ones being something called IgA.
IgA's main job is to protect the mucous membranes
from invaders like bacteria, viruses, fungi, and parasites.
Science has actually shown us that in an unhealthy gut,
these cells are compromised,
which decreases our defense against bacteria,
viruses, fungi, and parasites.
Neutrophils and macrophages are the cells
that gather in infected and inflamed tissues
to work to clean them and rid them of any bacteria
or toxins that are causing infection or inflammation.
In an unhealthy gut, these cells can't function properly.
A healthy gut also plays a huge role
in the production of interferons, cytokines,
and other regulators of the immune system
that are responsible for fighting off viruses.
So in simple terms, what does this mean?
In a healthy gut, we can fight off against invaders
through the cells listed on the screen.
When our gut is compromised, so is our immune system,
leaving us at risk for a whole slew of problems
like viruses, autoimmune disorders, cancers,
among many other things.
So in closing, we can see how important it is
for our gut to be functioning properly.
When we don't have a healthy functioning digestive system
and all of our accessory organs aren't doing their part,
it can lead to illness and disease.
In the next lesson, I wanna take a deep dive
into metabolism and thyroid health
to help us complete the picture of how the body works
so we can have a foundational understanding of health.
This will allow us then to appropriately understand
how to apply the six pillars of health for optimal wellness.
So I will see you in the next lesson.