A Digestive Journey: From Top to Bottom - and How to Improve it!

When you put something in your mouth, are you thinking about how it gets from point A to point B? 

Digestion is a fascinating process that begins even before food enters our mouth, and continues its journey through the various stages of the digestive system. Our digestive system is almost a separate world from the rest of our body (if it’s working correctly), and is an extension of the outside world. 

Today, we'll explore the journey of food from the top down, aiming to understand each digestive organ and its vital role. The main goal of digestion: Breaking down large, insoluble food molecules into smaller, water-soluble ones for absorption into the bloodstream and eventual energy production. In other words, turning food into energy. 

Mouth: The Gateway to Digestion

The journey begins when we put food into our mouths – even slightly before that. When we see and smell the food we are preparing, the salivary glands kick in to produce more saliva in anticipation. Then once we start to eat, the saliva contains an enzyme, known as amylase, that starts breaking down the food. Our taste buds not only allow us to taste the flavor, but they evaluate nutrients and signal to the body that we’re about to start digesting. 

Do you love/crave sweets? Sweetness in our food often indicated safety in the wild for our ancestors as opposed to bitter or sour (maybe our chocolate cravings are evolutionary and not our fault!) 

We renew our taste buds weekly, and their decline as we age impacts our perception of flavors. So if you have noticed yourself adding more and more salt as you age, this is likely why. And if you take a break from sugar for a week, you will notice that it doesn’t take much to get that sweet taste after - even a raspberry can be like dessert because your taste buds have changed during your break. Give it a try!

This is also where I have to highlight the importance of chewing our food. Our stomach doesn’t have teeth. This is our chance to ease the entire digestive process, right at the beginning! Ideally, we’re chewing 25 times per bite. (yes, 25 times!) If we don’t chew properly then we are asking so much more of the rest of our digestive tract. So see if you can slow down and chew a bit longer. And eating mindfully, without the distractions of work or electronics, has been shown to increase our digestive enzyme production and improve our digestion. 

The next organ we encounter along our trip is the esophagus.

Esophagus

This 8-10 inch long pink tube connects the mouth to the stomach. Peristalsis, the wavelike muscular motions of the esophagus, move food downward. The lower esophageal sphincter (or LES) acts as a valve and gatekeeper, determining what goes into the stomach, and keeps stomach acid down where it belongs, in the stomach. When this process is working optimally, food is worked down with small muscle contractions and moved into the stomach.

Conditions like gastroesophageal reflux disease (GERD) can lead to food regurgitation and burning sensations – also known as heartburn or acid reflux. High stomach acid tells our LES to stay closed, creating a barrier between the esophagus and stomach. 

When stomach acid is too low, our LES will open, creating an opening for food and acid to come back up. Heartburn is mainly caused by LOW stomach acid, not high. It’s quite the opposite of what we’ve been taught. You see, when there isn’t enough acid, the LES doesn’t close tightly and food from the stomach - which is still more acidic than what the esophagus likes - comes back up and we feel a burn.

Lifestyle changes are crucial for managing GERD – like managing stress and paying attention to diet. Spicy foods, fried foods, coffee, tomato sauces, citrus, chocolate, smoking, and eating close to bedtime are all triggers too. 

There are other factors that can cause heartburn like hiatal hernias, which is when the stomach is moving up into the diaphragm, and H. pylori which is an infection in the stomach that causes heartburn and ulcers. Managing these factors will keep your heartburn to a minimum.

Stomach

Positioned on the left side of the upper abdomen, the stomach is a muscular organ that churns food and releases acid and enzymes to break it down. Acidic conditions not only aid digestion but also protect against germs. No matter if we wash our food and hands, buy organic, or grow our own food, we will be consuming some bacteria. The conditions in our stomach should be acidic enough to take care of it.

However, age-related decreases in stomach acid and the use of proton pump inhibitors (PPIs) can pose challenges. PPIs may lead to infections, decrease nutrient absorption, and have a rebound effect upon discontinuation. If you’re on a PPI, quitting cold turkey would cause a rebound effect. If you plan to discontinue use at any time, it’s best to do it very slowly and with a doctor’s guidance. 

After our food gets processed here, it moves on to the small intestine. 

Small Intestine

The small intestine, a tubelike organ about 20 feet long, connects the stomach to the large intestine. This is where the absorption of nutrients takes place, facilitated by segmentation and peristalsis (the tiny wavelike motions we talked about before). 

The small intestine is not really “small” at all, except that it has a smaller diameter than the large intestine. It has grooves and waves that create a massive surface area for optimal absorption of nutrients and water. If we laid out our small intestine, it would have the same surface area as a tennis court! Not so small after all. 

Supporting players like the gallbladder and pancreas contribute bile and digestive enzymes, respectively. Bile is made in the liver and stored in the gallbladder until we eat a meal that contains fat. Then the bile is released into the small intestine and helps emulsify fats for absorption. In allowing fat to be absorbed, bile also allows us to absorb our fat soluble vitamins - A, D, E and K. 

Digestive enzymes made in the pancreas are released into the small intestine when we eat. These help to break down proteins, fats and carbohydrates. Each day our pancreas makes about 8 ounces of digestive juices for us! 

The small intestine is a very important organ. As the food passes through here, we absorb our nutrients to later be used to make energy. To do this, the small intestine has a very thin lining - only one cell layer thick. This lining acts like a screen door to let only the nutrients in but keep the bad things out - bacteria, viruses, undigested food, etc. When this very delicate lining breaks down, we get intestinal permeability, otherwise known as leaky gut. 

Leaky gut, a condition where the selective barrier breaks down, occurs due to factors like medications (NSAIDs, PPIs, birth control pills, steroids and antibiotics), stress, infections, and a poor diet. 

I’ve talked in depth about the effect of leaky gut on the body (trigger for many, many chronic conditions), as well as some ways to remedy it. But some places to start are to switch to an anti-inflammatory whole foods diet, manage stress daily, lessen your dependence on certain medications and support digestion with enzymes and probiotics. Please don’t stop any prescription medications without discussing this with your doctor.

Large Intestine

Despite its name, the large intestine is only about 5 feet long. The large intestine (or colon) absorbs mostly water and electrolytes from indigestible food waste, forming a solid stool. 

The large intestine is home to most of our microbiome - a rainforest of bacteria, viruses, parasites and yeast that help protect the gut. The bacteria in the microbiome break down complex dietary fibers that we can’t break down on our own into short chain fatty acids, which act as fuel for the cells in the gut lining.. The microbiome also produces enzymes necessary to make certain B vitamins and vitamin K. Other important roles of the microbiome include maintaining a healthy immune system and producing neurotransmitters that can affect our mood through the gut-brain axis. 

The colon can experience various digestive issues, including diverticular disease, inflammatory bowel disease, constipation, diarrhea, infections and colon cancer. Allowing the stool to leave our body daily is so critical. Our body is trying to rid itself of harmful toxins and waste products so pooping everyday is a must. If you are not having a bowel movement everyday, please see our blog called Tips for Healthy Bowel Movements. As you can see maintaining a healthy colon is critical.

Anus: The Final Stop

Finally, the digestive journey concludes at the anus, where stool is expelled. 

As you can see, the process of digestion is not only complex, but is so important in maintaining health. There are lots of places for this process to break down. I suggest starting with improving your diet, sleep, exercise and stress management to help improve your digestion. If you still need help, that’s what I’m here for. Sometimes doing a functional stool test can give us many answers as to what’s at the root cause of your struggles. Reach out if you need some help.