digestion · Foundations · nourish

Digestion: Turning Food Into Stuff

This is the second post in a series on the Foundations of Health. Go here to read part one.

This post is about digestion,  perhaps the most important foundation for health, which is why it gets to go first (well, second after food 🙂 )

On an unrelated note, I signed up for Roller Derby. I’ve been to two Derby 101 practices, and man am I feeling it! Turns out, I’m not terrible. Looks like those 12 years of figure skating are finally paying off. Thanks Mom! Don’t ask me why I decided to go from not skating since I was a kid to the most badass form of roller skating one can do. Apparently that’s just the way I roll…literally. It will be a while before I earn my derby name, but suggestions are always appreciated!

My new skates!
My new skates!

Ok, back to business.

Digestion: An amazing process that each of us do multiple times a day. But how many of us actually know what the heck is going on? And how can you address any of the number of things that can wrong with digestion if you don’t know how it’s supposed to happen?

Before going back to school for nutritional therapy, this was pretty much my understanding of digestion (it’s a video…you should watch it):


Mind. Blown.

But there all kinds of things that happen before the food you eat becomes something the body can actually use. A wise instructor I once had said something to the effect of most people know more about how their cell phone works than how their own body does. I never ceased to be amazed by the way the body operates.

For those of you reading who are like me and have no idea how digestion works, here is the quick and dirty tour of your digestive system:

Step 1: Digestion truly begins in the brain. When you think about/see/smell food, your brain starts sending out the alert to all the major players that something is going down.

Step 2: You put food in your mouth and start to chew. Your teeth break food down into smaller chunks.Chemicals in your saliva start the chemical breakdown of the food. Hopefully you’re chewing thoroughly to really get things broken down.

Step 3: Food travels down your esophagus to your stomach, where bolus (broken down food) is churned and mixed with  gastric juices secreted from millions of cells in the lining of the stomach. This highly volatile mixture serves many functions. Hydrochloric acid helps kill pathogens you may have ingested. Pepsinogen works with HCl to break down proteins into peptides (smalls strings of amino acids).

Step 4: After the contents of the stomach have been churned for a while and the pH level of the stomach is juuuuust right, it triggers the pyloric sphincter to open and release the chyme (all the stuff you just ate) into the first part of the small intestine, called the duodenum.

Step 5: This is where the magic happens. Most of the absorption of nutrients happens here, in the small intestine, with the help of a few friends like the gallbladder and pancreas. When the very acidic chyme enters the duodenum, mucous is secreted from the intestinal lining to protect it and to make the chyme less acidic. While this is happening. the small intestine is also secreting two hormones: secretin and cholecystokinin (CCK). The secretin tells the pancreas it’s time to start re;easing bicarbonate and pancreatic juices, which further break the chyme down into usable nutrients. CCK tells the gallbladder it’s time to start releasing bile, which is necessary to break down fats. CCK also happens to send a message to your brain that says you’re full…hence the advice to eat slowly!

Step 6: Now that the stuff you’ve eaten has been broken down, it somehow needs to get to where it’s needed to you know…actually do stuff! Chyme is now broken down into amino acids and polypeptides (proteins), glucose (carbs), and fatty acids and glycerol (fats), and as the whole gang moves through the rest of the small intestine nutrients are absorbed by millions of finger-like villi. The nutrients are then transported through the lymphatic system and the bloodstream to fulfill any number of needs: energy, repair, growth, you name it.

Step 7: The large intestine brings up the rear of the digestive train. Some leftover nutrients are absorbed in the small intestine, thanks to you friendly neighborhood gut flora. Water is recycled back into the body. This is also the stage where the poop is made. Solid waste is formed and leaves the body.

By then, you’ve probably eaten again and the whole wondrous event happens again!

So there you have it, the quick and dirty version of digestion.

Stay tuned for the next part: Blood Sugar!


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