Refers to your bodies ability to break down whatever substances you consume down into their simplest forms is essential to our health.1 Many would argue, and I would agree, that our bodies ability to digest something is of greater importance than what foods we are eating. This is not to say that the quality of the food you’re eating is not important, as it is extremely important, but instead is adding another layer on top of that.

A Simple Description of Why A Healthy Digestive System is Important

In simplest terms, the healthier our digestive systems are the better we digest foods, and/or beverages. The better our ability to digest something the more nutrients our bodies will be able to assimilate (utilize), thus benefiting every one of our metabolic systems (endocrine, cardiovascular, etc). In order to aid our digestive system health, it’s important to first understand how our digestive system works.

Defining the Digestive Tract

Gray’s Anatomy,2 is one of, if not the most comprehensive and definitive publications of human anatomy. This reference defines the human digestive tract as a “Musculo-membranous tube, about 30 feet in length, extending from the mouth to the anus, and lined throughout its entire extent by mucous membrane.” Although this is an oversimplified description of an incredibly complex system it provides an excellent starting overview.

The Digestion Process

Mouth & Esophagus

Digestion begins in the mouth as saliva is produced to begin the chemical breakdown of the organic substance (food/beverage) and chewing acts as the mechanical breakdown. Then the partially broken-down food moves down the esophagus and enters the stomach.


Once in the stomach, the stomach stores the food and mixes it with a variety of different digestive enzymes (dependent upon the type of food consume) creating a substance known as “Chyme.” At the same time gastric glands, the glands in the stomach, secrete Hydrochloric acid (HCL) further breaking down foods so they are ready to pass into the small intestines.3

Small Intestines

The small intestines, as you shall find out later, is probably the most important section of the entire digestive tract. As food passes into the small intestines it stimulates the production of Secretin and CCK (Cholecystokinin), which signals the stomach to moderate contractions (cause the feeling of fullness) and to release digestive/hormonal secretions from Pancreas and Gallbladder. Nutrients are absorbed via villi, microscopic finger-like projections, that cover the small intestines entire inner lining.4

Large Intestines (Colon)

Finally, food reaches the large intestines (the colon) where it is stored as waste then later excreted. Or foods that contain certain substances, such as fiber, which cannot be broken down by our bodies digestion process are broken down by the symbiotic (friendly) bacteria that reside in our large intestines.5

Importance of the Small Intestine

Accounts for Most of Our Digestive Tract

The small intestine is an area of particular interest when talking about the digestive system. As mentioned earlier, it is in my and many experts’ opinions, the most important part of the intestinal (digestive) tract.  The small intestine accounts for over 56% of the entire intestinal tract. Furthermore, it is responsible for 90% of caloric absorption. Yep you read that right 90% of the calories you take in are absorbed in the small intestines, that alone is a big deal.

Impacts Our Immune System

Another factor that is important to mention is that the small intestines has a profound impact on the immune system. For the largest mass of immune cells found in our entire body is seen in the small intestines.7

Optimal Digestion, Plays a Major Role in Overall Health

Adequate, if not optimal, digestive system function is essential to our health. For if even one part of this system does not function well it could result in numerous problems such as not being able to break down foods into their usable forms (nutrients), allowing undigested food particles to get through our intestinal lining and into our bloodstream where they cause an autoimmune reaction, dysregulating hormone production, and will weaken immune defenses.6

Small Intestines, Plays a Major Role in Digestive Health

As you can see maintaining the health of our small intestine is essential to our overall health. The problem is that the small intestines only has a thin, (single cell layer thick) protective mucous membrane and is much more susceptible to damage (which results in what is called leaky gut) than the large intestine. This damage is often what underlies many immune and autoimmune conditions, food intolerances and the malabsorption of nutrients.7 I hope it is now becoming clear why the small intestine is considered to be the most important part of your entire digestive tract. I’ll end with that and next week I’ll go over the small intestines and its association with many diseases and syndromes. I’ll also provide steps that you can take to get your digestive health back on track.

  1. https://en.wikipedia.org/wiki/Human_digestive_system
  2. https://www.amazon.com/Grays-Anatomy-Anatomical-Clinical-Practice/dp/0702052302
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1225731/
  4. https://www.livescience.com/52048-small-intestine.html
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2493210/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513829/
  7. https://www.sciencedirect.com/science/article/pii/S0958166914001657?via%3Dihub