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Two Gut Organisms: A Destructive Co-Dependent Relationship

Balance of bacteria and organisms in your gut matters more than you may think. When the bacteria are out of balance you may experience symptoms such as bloating, cramping, gas, belching, constipation and diarrhea.

There are two types of organisms in the gut. One group is bacteria, the other is an archaea—a one-celled organism like a bacteria that also inhabits the gut. An over growth of archaea that produce methane gas causes constipation, while overgrowth of hydrogen sulfide producing bacteria causes diarrhea. Archaea can also cause gastroparesis, a condition in which the signals to the digestive system falter or slow down, thus slowing the digestive processes down.

The Vicious Cycle Inside Your Gut

If you have diarrhea-related Small Intestinal Bowel Overgrowth – SIBO, you are suffering from an overgrowth of hydrogen-producing bacteria in your small intestine. Bacteria produce hydrogen gas as a byproduct of carbohydrate fermentation in the gut. An overgrowth of bacteria also produces toxins that irritate the gastrointestinal lining that causes diarrhea. Most of these toxins overload the TRPV1 receptors in our gut, greatly increasing water concentration and gut movements (peristalsis) that causes diarrhea as a defensive mechanism to protect the body from the toxins and bacteria.

If you suffer from constipation, you likely have an overgrowth of archaea. Archaea in the digestive system feed off of hydrogen that other bacteria produce during the fermentation of carbohydrates in our gut. Archaea then produce methane as a byproduct of their digestion. The more fermentation and hydrogen gas that occurs in the intestines, the more methane archaea will be able to produce. Methanobrevibacter smithii seems to be the most dominant of the archaea species in the gut, compromising at least 90 percent of the archaea gut flora.

Increased hydrogen-producing bacteria and poor lactose absorption have been correlated with an overgrowth of archaea in the gut and gastroparesis (slowing of digestive activities) and constipation. Decreased migrating motor complex function (or MMC, the process by which the digestive system eliminates waste) also leads to an increase of hydrogen (feeds archaea) and methane concentrations in the gut, which causes excessive bloating. People suffering from archaea overgrowth also have significantly lower colon pH, which can help protect the bacterial overgrowth from immune elimination.

How does archaea dysbiosis further hinder MMC function to the point of chronic constipation? Serotonin (5-HT3 / 5-HT4) is one of the biggest neurotransmitters in the gut associated with regulating proper gut function. Lower amounts of serotonin in the gut leads to reduced function and chronic constipation in methane-dominant SIBO. Reduced activation of the serotonin receptors in the ileum greatly slow down both gastric emptying of the stomach, which can cause gastroparesis symptoms, and emptying of the small intestine, which can lead to SIBO.

Stopping the Cycle

Bacteria and archaea in the gut feed off of each other, so how do you stop the back and forth of bacterial or archaeal overgrowth?

Taking a probiotic while following the FODMAP diet (explained in this article) is usually the best way to maintain balance of the gut bacteria. Without testing to determine exactly what your imbalance is, take a full-spectrum probiotic. Reducing FODMAP foods takes away the food source for these bacteria. If your problems are pronounced and doing the diet does not result in symptoms, I recommend seeing a functional medicine practitioner for additional help. Once you’ve achieved balance (are no longer experiencing symptoms), often the FODMOP diet isn’t necessary, though a plant-centric with adequate protein and healthy fat such as the Paleo diet is still recommended. Regular exercise can also help to regulate the MMC function of the gut.