I’m sure you have all heard the expression, “we are what we eat”, well that’s only partly true because actually, “we are what we absorb”. Only when our digestive system is working properly by breaking down the food we eat into basic molecules of amino acids, fatty acids and simple sugars, can our bodies actually use those building blocks to produce energy and be used to make proteins.
There are so many steps along the way:
1. Digestion (the physical breaking down of the foods).
2. Assimilation (the taking in of the broken down foods as basic simple molecules through our gut wall).
3. Nutrient distribution (the movement of those molecules to where they are needed).
4. Tissue uptake (the movement of the molecules into our cells).
5. Use of those molecules within each cell to make it function, grow, replicate or not.
As all osteopaths and other manual therapists learn, structure governs function, so lets start by looking at the physical structure of the intestinal wall and how that governs the job it has to do.
The digestive Tube
This tube leads from our mouth to our anus with organs attached to it along the way. Although inside our bodies, our digestive tube is constantly exposed to everything we put into our mouths from the outside world. So that’s not only food & drink but also bacteria, yeasts, parasites and viruses. As a consequence, our body needs a really well-functioning immune system to ward off the unwanted microorganisms.
Our body has to be able to identify and sort the “wanted” from the “unwanted”, an amazing task. It has to absorb what it wants and excrete that which is doesn’t want. So remember, the food that we’ve eaten is not strictly part of us until it is taken across the all-important intestinal membranes into our blood and lymphatic system, ready to be transported to our cells.
So let’s look at those membranes…
You can see that the wall itself is folded over and over on itself, like little waves or the woollen loops of a long fluffy carpet. This makes a massive difference to the surface area over which food can be absorbed. This, coupled with the fact that the whole tube measures some 10-15 meters, gives it a surface area that has been measured at 200 times the area of our skin!
Now let’s look at the individual cells of the intestinal wall.
They look like little elongated bricks, packed very closely together without any mortar in between. They have several jobs to do:
1. They secrete an anti-bacterial, mucus covering, to protect themselves. This mucus layer is also where all our beneficial bacteria live. More on that very important topic in another post.
2. With the help of signals from our immune system and our resident bacteria, the cells allow digested proteins and sugars in and onward, through to the blood stream and fats into our lymphatic system.
3. They recognise unwanted foreign material and keep it out.
4. They release or export the body’s waste products and toxins into the digestive tube for elimination, the reverse of absorption.
These gastrointestinal cells are called enterocytes. They have a tremendously important job to do for the sake of our whole body’s health. A poorly functioning gut lining or membrane can lead to a whole host of problems, so it’s important to know how to look after it. More of this in another post.