Inside Guide to Your Digestive System
Today we are deep diving into your digestive system.
Digestion refers to the process through which your body extracts the nutrients it needs from the food you eat. Having a healthy digestive system is important for your overall health and wellbeing. Your digestive system includes your gastrointestinal tract, all the way from your mouth to the loo.
Understanding your digestive system is a cool way to be more mindful when eating and also appreciate the unique ways your body is working to extract vital nutrients for you everytime you eat.
Have you ever walked past a bakery and smelt freshly baked bread wafting through the air and you noticed your mouth start to salivate or a slight grumble in your stomach? At this moment you are experiencing the smell, sight and thought of food and in anticipation your brain sends signals to your digestive system to get ready - food is on its way! This process is known as cephalic digestion.
Once the warm, freshly baked bread enters your mouth little proteins in your saliva known as ‘enzymes’ get to work breaking down the carbohydrate components of the bread, while also providing moisture to help form a ball (bolus) ready to swallow!
Meanwhile, through chewing your teeth and tongue start mechanically breaking down the bread into smaller pieces, this increases the surface area that enzymes have to work on and allows food to move throughout your gastrointestinal tract more easily. Once you swallow the bolus (ball of food) it moves into your oesophagus and then into your stomach.
Now the party really gets started.
Your stomach acts kind of like a muscley washing machine, churning the food into smaller and smaller pieces. The lining of your stomach releases acid (bile) which helps in breaking down the protein component of the food (making it easier to digest in your small intestine) and also warding off any potential pathogens (i.e. bacteria) in the food. Your stomach acid also helps in releasing certain nutrients in the food (i.e. iron). Once the food, enzymes and stomach acid are nicely mixed into a semi-liquid substance (chyme) it’s ready to enter your small intestine.
Slowly your stomach releases small amounts of chyme into your small intestine where the food comes into contact with bile from your gallbladder and digestive enzymes from your pancreas. The bile from your gallbladder (produced by your liver) is kind of like dishwashing liquid - as it helps in breaking down (emulsifying) the fat particles making it ready for absorption. Once inside your small intestine the bile and digestive enzymes work to further breakdown the food.
Your small intestine is lined with tiny hair-like projections (called villi) which considerably increase the surface area for absorption (to about 200 square meters!). The villi inside your small intestine are about 1mm thick which allows for nutrients to be absorbed directly into your bloodstream. Approximately 90% of nutrient absorption occurs in your small intestine. Your small intestine is very long (varies between 3-5 meters) and requires special muscle contractions (peristalsis) to help in moving the food along (another reason our gut grumbles) and into our large intestine. The process of moving food along your small intestine can take between 2-6 hours.
Ok, so now the food has entered your large intestine (colon) which funnily is shorter than your small intestine (about 1.5 meters long), and gets its name due to its width (about 7cm wide). This is where excess fluid and electrolytes are reabsorbed and undigested food and waste products are turned into stool (poop). Your large intestine is also home to your gut microbiota (your gut bacteria) and here is where the clever little critters get down to business fermenting your undigested food (namely fibre) and producing beneficial compounds like short-chain fatty acids that have a range of health benefits, as well as producing vitamin K.
Voilà, the inside guide through your digestive system.
Next time you have something to eat, try taking time to notice the feeling of saliva in your mouth and how it softens your food, or maybe the little grumbles in your gut! Oh and make sure to include something to eat for your gut critters (gut microbiota) like fibre found in plant foods or fermented foods and of course lots of water to keep things moving!