Side Effects of Inulin

Intestinal Discomfort from Inulin

You may have heard of the many benefits of inulin, but what do you know about inulin side effects? Any time you decide to try new diet products and aids, it is always important to learn about side effects or other concerns ahead of time, and inulin is no exception. While most people tolerate this product well, being aware of potential side effects and how to prevent them will make your experience with inulin a much more agreeable one.

Intestinal Discomfort

By far, the most commonly reported side effect of inulin ingestion is intestinal discomfort. As a prebiotic, inulin feeds the bacteria that live in your digestive system. This is one of the benefits of inulin and is a commonly cited reason for inulin use. However, as your intestinal flora digest the carbohydrate, they release metabolic gases as a product of digestion.

According to the Journal of Nutrition, you may experience the effects of bacterial metabolism in a number of ways, including:

  • Flatulence
  • Bloating
  • Stomach noises
  • Belching
  • Cramping

Whether these symptoms are severe enough to warrant discontinuation of the product depends on a variety of factors. Some individuals seem to simply be more sensitive to the effects of inulin. In the book Inulin-type Fructans, author M.B. Roberfroid notes that while the majority of individuals using inulin experience no significant side effects at high doses, roughly one to four percent of test subjects experience bothersome symptoms even at very low doses of the product. This may be due to individual morphology, biochemistry, or the existing populations of microflora in the gut. Additionally, personal aesthetic factors will determine what level of symptoms can be described as bothersome. An acceptable amount of intestinal gas for one person might be unacceptable by another's standards, which makes it difficult for researchers to accurately quantify these types of inulin side effects.


Inulin is classified as a dietary fiber. Like any dietary fiber, inulin encourages transport of water into the intestines. Inulin has a relatively small particle size compared to other fiber types, such as wheat bran or oat bran. The small particle size tends to exaggerate this water-drawing property. Most people will not encounter serious diarrhea when taking inulin at low doses, but caution is required to be sure you do not accidentally initiate an unpleasant reaction.

Proliferation of Harmful Bacteria

As a prebiotic, inulin is intended to encourage the development of good bacteria in your digestive system. It accomplishes this by feeding existing populations of bifidobacteria and lactobacillus, allowing these friendly bacteria to crowd out disease-causing microorganisms and create an inhospitable environment for pathogens. However, some would argue that providing food specifically for gut flora could create more problems than it solves. If the existing populations of bacteria contain certain harmful bacteria, there is no guarantee these organisms will not take advantage of the ready food source in the same way good bacteria do.

Allergic Reaction

There has been one reported case of anaphylactic allergic reaction to inulin. The product has been used for decades to assess kidney filtration rate in individuals with certain kinds of kidney disease. In 2007, and 11-year-old boy was undergoing such a test using inulin, and experienced severe allergic reaction and relapse of kidney disease. While this is an extremely rare occurrence, it is important to be aware the risk is there,

Preventing Inulin Side Effects

When you first start using inulin, it is recommended you begin with a very small amount to assess how your body reacts to the substance. If you tolerate the substance well, increase the dosage gradually until you are able to use the amount you require. By gradually introducing inulin to your system, you will be able to accurately gauge your personal tolerance of the product and prevent any severe side effects that may otherwise occur.

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Side Effects of Inulin