We chew, we swallow, then we wait a wee while and eventually something comes out the other end.. simple right?!.... not so fast.
What many of us fail to give a second thought to is the amazingly complex and clever processes that our various organs go through. They take this food, break it down into a more usable form, whip out the bits that are useful to us, and send the rest cruising through the lower bowels and out into the open.
Only the very beginning and end of this process is conscious action. We chew our food, breaking it down, making it easier to digest. Then we swallow. Here our autonomic nervous system instantly kicks in and we are essentially running on auto-pilot. The nerves and muscles in our neck work together to move the food down the oesophagus and into the stomach… and the speed that this happens is quite amazing!
The stomach is a sac-like organ with several super important functions. Firstly, it secretes hydrochloric acid creating a highly acidic environment. This acid acts as our first line of defence against any bugs or germs in food, as generally they cannot survive these conditions. The stomach also releases digestive enzymes that begin to break down protein and fats into smaller pieces. Finally, it has a rigorous churning action, like a cake mixer, but with strong muscles instead of the mixing blade. These work to mix the food well and break it down ready to move onto the next stage.
Once the stomach has done its job, it doesn’t just dump all it’s contents into the small intestine in one go – it has a clever little sphincter, which acts like a bouncer at a nightclub, letting in a little in at a time, depending on how full it is on the other side.
The small intestine is the major site of digestion and absorption.. and it needs a little help to do its job well. This is where the pancreas comes in to play.. nestled next to the top of the small intestine, it releases bicarbonate which neutralises the highly acidic stomach contents so they don’t damage the rest of the digestive tract. The presence of partially digested food in the small intestine also stimulates the release of digestive fluid from the pancreas, containing enzymes that break down carbohydrates, protein and fats into even smaller pieces. Our body is so clever - it releases these enzymes in an inactive form and once in the small intestine, their activation is triggered. This is to stop these enzymes digesting the pancreas itself. The protective lining of the small intestine prevents this from happening there.
Next, we have some help from the liver and gallbladder. The liver produces bile which is then stored in the gallbladder until needed. When fat is detected in the small intestine, this bile is released. Biles job is to emulsify the fat. Fat likes to cling together in clumps, so the role of an emulsifier is to break this down and disperse small particles of fat. This process is similar to when emulsifiers are added to some of our foods – things like salad dressings. If they were not included the fat would all clump together and separate from the liquid part.
Once everything is broken down, we absorb what we can, and the rest makes its way down to the large intestine – humble home to our trillions of gut bugs!
There are SO many different kinds of gut bugs and their composition largely depends on our eating habits. Large amounts of nutrient and fibre poor processed food promote a less favourable composition, while a wholefood, adequate fibre diet feeds the good bugs and helps them to thrive.
They have lots of different jobs like releasing more energy from food in the form of short chain fatty acids, and producing Vitamin K and some B Vitamins. Once they are done, the remaining food then moves into the rectum. Here our conscious action kicks back in (well, for most of us anyway), and we have conscious control over when we open the gates and let everything out, i.e we poop.
As you can see even from this simplified explanation, these processes required coordinated activity from many tissues organs and tissues for things to go well. Sometimes our lifestyles, what we eat, and how we eat can cause things to go a little wrong. Look out for part 2 for tell-tale signs and symptoms + how I can help you get your gastro function back on track.