SIBO and food intolerance

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SIBO and food intolerance

Medically reviewed by:
Dr James Freeman

How SIBO bacteria damages your intestine lining and can lead to food intolerance

SIBO and dysbiosis can make your life a misery and create many challenges in breaking down foods.[1] This leads to discomfort but it actually comes from an inability to break down certain foods.

Although you might test negative for lactose intolerance, you may still be intolerant because of the bacteria living in your small intestine. Therefore, people often find it helpful to go on diets that eliminate a large portion of certain food types. It doesn’t address the root of the issue, but it can mitigate some of the discomfort experienced daily and maybe a step in a multifaceted treatment plan.

The reason behind this is complicated, but we have listed the science below in simple terms to try and help you better understand what is going on.

Issues digesting Carbohydrates

In your small intestine, you have something called the glycocalyx. These take the form of finger-like projections that line your small intestine. You also have microvilli on the cell. They are so small that the naked eye can’t see them, but they have an important job. They absorb nutrients from your food. The glycocalyx is the protective glycoprotein layer that has enzymes for carbohydrate digestion. Carbohydrate digestion becomes a problem in SIBO because the membranous phase is disrupted.

There are three types of carbohydrates:

Monosaccharide – These are carbohydrates with a molecule of sugar in their structure. (Glucose, fructose, ribose)
Example: Table sugar which is made from glucose and fructose.

Disaccharides – These are carbohydrates with two molecules of sugar linked together in their structure (sucrose, maltose, lactose)
Example: lactose (the sugar in dairy) made out of glucose and galactose

Polysaccharides/Polymers – These are carbohydrates with multiple molecules of sugar linked together-
Examples: Starch and cellulose, which are in vegetables, fruits, whole grains and legumes

Carbohydrates digestion on the body goes through many processes, depending on the type of carbohydrate. Larger polysaccharides like starches from fruit, vegetables, and legumes are broken down into disaccharides in the intestine’s lumen by enzymes.

Disaccharides are broken down into monosaccharides by enzymes that are present in the glycocalyx. With SIBO, the membranous phase of digestion is disrupted due to the damage of the glycocalyx by the SIBO bacteria; therefore, SIBO can cause carbohydrate intolerances to things like secondary lactose and fructose intolerance.[2]

That is a little hard to understand, but essentially, a key component of carbohydrate digestion has been impaired by the SIBO bacteria, leaving you unable to break down carbohydrates effectively. Another type of SIBO can cause the recycling of toxins (methane) and lead to weight gain.

1 Rowland et al., 2017
2 ZHAO et al., 2010

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