The Most Important Part of Our Digestive Tract

Last week, I introduced that the small intestine is currently thought of, as the most important part of the entire digestive tract. This is very logical since it makes up most of our digestive system and 90% of caloric absorption, thus most nutrient absorption happens in this organ.1 Additionally, if we look at the bodies entire gut ecosystem and the methods for creating a healthy internal environment in your gut ecosystem, it’s usually the intervention that works best for the small intestines that have the most overall benefit.

The Small Intestines is Fragile

Why do the interventions that work best for the small intestines have the greatest effects? Because it is most commonly the small intestine that is damaged since it is fragile and more prone to dysfunction than any other section of our digestive system. This fact is supported by the small intestines association with diseases such as celiac disease, hypothyroidism, and irritable bowel syndrome.

Celiac Disease & The Small Intestines

Celiac disease is considered the most severe form of gluten intolerance as it causes inflammation and autoimmune damage to your gut. Several human studies have shown that there are increased amounts of bacteria and increased bacterial diversity in the small intestines of those with celiac disease. Essentially, this means they have a bacterial overgrowth in the small intestines.Interestingly bacteria that are considered to be healthy bacteria can also overpopulate the gut and cause problems. As one study showed that many children with celiac disease, when compared to healthy control participants, have an increased diversity of the healthy species bifidobacteria.3 Another study showed this same increase of bifidobacteria in adults with celiac disease.4 Although not all research agrees with, there is certainly enough evidence that suggests that those with celiac disease may or often have bacterial overgrowth in the small intestines.

Hypothyroidism & The Small Intestines

Hypothyroidism, otherwise known as an underactive thyroid, is a condition in which the thyroid gland doesn’t produce enough of certain important hormones. It is one of the most common thyroid disorders. Hypothyroidism also seems to have the same potential cause behind it as celiac disease, too much bacteria in the small intestines. As there is research showing that this thyroid condition is associated with small-intestinal bacterial overgrowth.5 However, it is important to ask the question does this overgrowth of bacteria occur because of the hypothyroidism itself? Or said another way does hypothyroidism cause the overgrowth, rather than the overgrowth causing the hypothyroidism? Experts don’t know for sure, but bacterial overgrowth has been seen in both hypothyroidism and hyperthyroidism (over-active thyroid).6 This suggests that the bacterial overgrowth is not being caused by thyroid disease but rather that the overgrowth is causing the thyroid disease, or at least potentially.

Irritable Bowel Syndrome & The Small Intestines

The small intestine also has a strong connection with irritable bowel syndrome (IBS). SIBO is known to cause gas, bloating, constipation, diarrhea, and abdominal pain – all of which are the primary symptoms of IBS. It is of no surprise then, that research has shown up to 78% of IBS may be caused by an overgrowth of bacteria in the small intestines.7

The First Step In Healing the Digestive System

(If an overgrowth of bacteria is the problem)

As you can see, what’s associated with all three of these conditions, and many others is an overgrowth of bacteria. Therefore, following the current guidelines for SIBO may also be the guidelines one should follow if they have celiac disease, hypothyroidism, or IBS. The current treatment guidelines for those with SIBO state that one should not feed their gut bacteria, or at least should do so very cautiously.8 This means that those with any form of bacterial overgrowth shouldn’t be eating high amounts of fiber or starch, foods that are considered pre-biotics, fermented foods, foods high in natural sugars, and especially foods with added sugars and refined carbohydrates. Although this is true for anyone dealing with a bacterial overgrowth, it is not true for everyone.

A Great Start. But…

And while this is a good place to start, as many who eat a typical western diet typically have an overgrowth of bacteria, it is only that – a good place to start. Next week, I’ll dive into what you can do if you want to optimize the health of your gut.