No. 02 Digestion 101

Gut health has become a hot topic in recent years, and for good reason.

Everywhere you look, there are new products and growing awareness around how to improve your gut. We’ve all heard that gut health is vital, but why exactly does it matter so much? What is the gut, and how can you tell if yours is healthy? These are the questions we’ll
explore in the coming weeks. Albert Einstein once said, “If you can’t explain it simply, you don’t understand it well enough.” We will explore & work to understand the gut so we can take better care of it — and it can take better care of us.

The gut is often referred to as the “second brain” as it plays a central role not only in digestion but also in regulating many aspects of our overall health. From breaking down food and absorbing nutrients to influencing our immune system and even our mood, the functions of the gut are far-reaching and complex. Today, we will gain a deeper understanding of what the gut is and how it operates inside us . Thanks to advancing research into the gut microbiome, scientists are learning just how powerful an impact our gut health has on everything from metabolism to mental health. In this article, we’ll explore the fascinating functions of the gut and we will start to peek into why maintaining gut health is crucial for living a vibrant, balanced life. Don’t worry about sounding professional. Sound like you. There are over 1.5 billion websites out there, but your story is what’s going to separate this one from the rest. If you read the words back and don’t hear your own voice in your head, that’s a good sign you still have more work to do.

Maybe this isn’t news to you but, the gut is not an organ. I repeat the gut is not a single organ. The gut encompasses our entire digestive system. And more specifically the
gastrointestinal (GI) tract, which includes all the organs involved in processing food, absorbing nutrients and eliminating waste. Often when people talk about "gut health,"
they are referring to the health of the stomach and intestines, where a lot of important processes occur but ultimately are just two parts of a larger whole.

Here’s a quick breakdown of the gutsy major components:

1. Mouth– Where digestion starts, with saliva breaking down food.

2. Esophagus – The tube that moves food from your mouth to your stomach.

3. Stomach – Where food is mixed with stomach acids to further break it down.

4. Small intestine – The long tube where most digestion and nutrient absorption happen.

5. Large intestine (colon) – Absorbs water and salts, leaving behind solid waste.

6. Rectum and anus – Where waste is expelled from the body.

And let’s not forget the trillions of microorganisms living in your gut — bacteria, fungi, and viruses — which help break down food, protect against harmful bacteria, impact immunity and mood regulation. We’ll dive deeper into these gut microbes in upcoming content.

The digestive process actually begins as soon as food enters your mouth. Picture this, you see a cookie. You want that cookie, you’ve been a very good girl (or boy) today and feel you should treat yourself to that cookie. As soon as you start taking those sweet sweet bites, your gut begins to get to work. You think you are just enjoying a circular dessert, but in fact your chewing is a sign to your body to start up the old digestive system. As you
continue to chew your food into smaller pieces, this increases the surface area for enzymes to work on. Your saliva contains amylase, which is an enzyme that starts breaking down carbohydrates into simple sugars right there inside your mouth. Even before you swallow, your body is starting to process that cookie!

 But wait there's more! Once you swallow, the cookie travels down your esophagus, imagine a water slide that has walls lined with muscles. This muscular tube connects the mouth to the stomach. The movement of food down this muscle tube happens through a process called peristalsis, which is a series of wave-like muscle contractions. These contractions push the food along, much like squeezing toothpaste out of a tube. To summarize your esophagus is similar to a toothpaste tube muscle water slide and your food is tooth paste. It's as simple as that. 

Just as you would exit a water slide into a pool panicking trying to make sure your swimsuit is intact and none of your bits are exposed.  The food you’ve eaten exits the esophagus into the stomach, met by a pool of powerful stomach acids (mostly hydrochloric acid) and digestive enzymes like pepsin, which help break down proteins. How does the stomach contain this powerful mixture without being singed from the inside out you ask, well the stomach's lining is coated in a mucus to protect your tummy’s inner walls from these strong acids. The stomach churns food into a semi- liquid substance called chyme (yum). This process can take a few hours, depending on the type of food you’ve eaten. For instance, fatty rib stickin foods stay in the stomach longer than simple carbs… like your cookie. Unless you are a sociopath and your chose oatmeal bran
raisin over chocolate chip. 

Next up on our journey down the bod is what I would personally consider the humble star of the show, the small intestine. This is where most of the nutrient absorption happens, and this process is divided into three important parts:

The duodenum is the first section of the small intestine, where digestion is completed. Receiving partially digested food from the stomach, bile from the liver, and digestive enzymes from the pancreas, these substances get to work breaking the fats, proteins, and carbohydrates down into smaller molecules for absorption. The duodenum also plays a
role in neutralizing stomach acid to protect the intestinal lining. The duodenum acts as a crucial mixing chamber that prepares food for further digestion and nutrient absorption in the upcoming jejunum and ileum.

The jejunum is the middle section of the small intestine and is primarily responsible for absorbing most of the nutrients from digested food. It’s lined with tiny projections called villi, which increases the surface area for maximum nutrient absorption. The villi are also lined with tiny projections called microvilli. Imagine it like fingers that then have hundreds of tinier fingers all over them. (Terrifying? Yes. Efficient? Also yes.)  The jejunum
absorbs carbohydrates, proteins, fats, vitamins, and minerals, transporting them into the bloodstream for use throughout the body. This section is crucial for providing the body with the energy and nutrients it needs to function properly. Any damage to the jejunum can lead to malnutrition and deficiencies.

The final part of the journey through the small intestine goes through the ileum, responsible for absorbing any remaining nutrients not absorbed by the jejunum. (one jejunum’s trash is another Ileum’s treasure I always like to say...)  Ileum plays a key role in absorbing vitamin B12, bile salts, and any leftover water-soluble vitamins. The ileum also has villi, though they are smaller and less dense than those in the jejunum. Ileum connects to the large intestine and helps regulate the flow of undigested material into the colon. The ileum is essential for completing nutrient absorption and ensuring the body gets everything it needs from the food before sending it off to the large intestine.

After most nutrients are absorbed, the remaining waste moves into the large intestine (street name: the colon). This section absorbs water and electrolytes, turning what's leftover into solid waste (poop). It also houses bacteria that help digest fiber and produce beneficial compounds like short-chain fatty acids (SCFAs), which support gut health and
we will explore further in the future. The colon plays a key role in immune function, monitoring and protecting against harmful pathogens.

Finally, after the nutrients have been absorbed and most of the water removed, the remaining waste moves into the rectum, where it’s temporarily stored until the body is ready to eliminate (poop). The rectum acts as a holding chamber, giving your body a chance to monitor and prepare for waste expulsion (like an actor waiting in their
changing room anticipating a show stopping performance). When the time is right, the waste is expelled through the anus, a process controlled by two key muscles: the internal anal sphincter and the external anal sphincter. The internal sphincter is involuntary and keeps the anus closed until it’s time to go. The external sphincter, however, gives us conscious control, allowing us to decide when to release the waste. This system ensures we don’t just eliminate waste at any random moment (thank goodness for that little feature).

This concludes our journey through the digestive system. My hope is that this has given you a more solid grasp on the powerhouse that is your gut. It’s not just about digestion — it’s the command center for your health, controlling everything from your immune system to your mood. This is just the tip of the iceberg. If you haven’t already, please make sure to subscribe to Boochi Mama’s email so you can continue to follow along as we go where no woman has gone before. (or as we learn more about your gut.) Next we will venture into the foreign world of the gut microbiome — and those tiny but mighty organisms living inside us. Do not miss it.