Day 28: The Gastrointestinal Tract

Dinner: Omelette; salmon; sauerkraut; veg shake.

Exercise: Jog in the morning; weights in the evening

78.5kg this morning. I absolutely did not get away with it. Just shows you what one night of drinking can do. I’ve decided to give up booze for the next month. That’s the plan anyway.

Gluten is probably the most vilified substance in the Paleo community. I discussed my experiences with it previously and briefly discussed how it causes damage to the gut. In order to understand this process better, we need to understand how food is digested. Today I’m going to explain the role of the Gastrointestinal Tract (GI Tract) in that process.

The intestines, gut, or bowels, are basically the same thing. They are part of your GI Tract; the system responsible for digesting food, sending the nutrition where it needs to go, and getting rid of the rest. By digestion we mean both the breakdown of the food, and the extraction and absorption of nutrition by your body.

Initially food enters your body via your mouth (hopefully). Chewing and saliva turn the food into a form that can be swallowed. Once swallowed, it travels down the oesophagus into the stomach. The stomach releases enzymes and churns the food into goo called chyme.

The next step is the small intestine. Up to this point no nutrition has been extracted. The stomach just breaks food down into a form from which the nutrition can be taken, it doesn’t extract any food. The small intestine contains bacteria that can extract nutrition from food. These are the probiotics referred to in yoghurt ads. You want healthy bacteria in your intestines. The small intestine itself is jumbled, like a pile of rope. This ensures that the food makes frequent contact the walls as it passes through. The walls are also curved to increase surface contact. The walls are further covered in villi to increase absorption again. This is important, as the walls of the small intestine are where the majority of the nutrition is removed and passes into the bloodstream.

The food passes from the small intestine to the large intestine, also known as the colon. The “food” is really faeces at this stage, however there is still some nutrition left. Bacteria in the colon digest the faecal matter to extract nutrients and water, much as the small intestine. Once this is done the faecal matter is passed on to the rectum, and you know what happens from there.

That, very simply, is the process of digestion. Clearly the small and large intestines play the most important roles. They determine which parts of our food are allowed to pass into our bloodstream, and which parts are sent to the rectum. It is crucial that this function is not compromised. How would you feel if they sent the nutrition to the rectum, and the faeces into the bloodstream?

Unfortunately, that is what can happen when you eat gluten. Gluten can create holes in the lining of your gut. If that happens your “leaky gut” allows toxins, microbes, undigested food particles and antibodies to travel throughout your body via your bloodstream. This often leads to a plethora of further problems. But that’s enough for today. I’ll discuss how gluten causes leaky gut tomorrow.