Chicory root inulin

What is chicory root inulin?

Inulin is a type of soluble fiber made of chains of fructose molecules, which is why scientists call it an inulin-type fructan. It is found naturally in onions, garlic, leeks, bananas and asparagus, but most supplements extract it from chicory root. Humans cannot digest inulin in the small intestine, so it reaches the colon intact. There, certain bacteria ferment it and produce short-chain fatty acids.

That selective feeding effect is what makes inulin a prebiotic. As NCCIH explains, prebiotics are nondigestible food components that selectively stimulate the growth or activity of desirable microorganisms, and products that combine a prebiotic with a probiotic are called synbiotics. PrimeBiome is designed as a synbiotic of this kind.

What the research says

Chicory inulin is one of the best-studied prebiotics. A systematic review and meta-analysis published in Critical Reviews in Food Science and Nutrition included randomized controlled trials lasting at least seven days. Across 50 studies and 2,525 participants aged 0 to 83, chicory-derived inulin-type fructans at 3 to 20 grams a day significantly increased the abundance of Bifidobacterium in the gut. The bifidogenic effect appeared in healthy people and in several groups with health problems, although not clearly in people with gastrointestinal disorders. The researchers also found beneficial effects on bowel function parameters in healthy participants, such as stool frequency and consistency.

This is reasonably solid evidence that inulin changes the gut microbiome in a predictable direction. What remains less certain is how much those changes translate into noticeable health benefits for any given person. It is also worth noting that one co-author group was affiliated with a chicory inulin manufacturer, which the review discloses.

Because the effects are dose-dependent and studies used at least 3 grams a day, we rate the evidence as moderate for gut microbiome and regularity at those doses. Amounts in the milligram range, as found in many gummies and capsule blends, have not been shown to do the same.

How it’s used in supplements

Inulin is sold as a stand-alone powder, added to fiber blends and probiotic products, and used in foods as a sugar or fat replacer. A common approach is to start with 2 to 3 grams a day and increase slowly, because fermentation in the colon can cause gas, bloating and cramping, especially in people who are sensitive to fermentable carbohydrates (often called FODMAPs). People following a low-FODMAP plan on medical advice may need to avoid it.

In PrimeBiome, chicory root inulin is the first item listed in a 430 mg proprietary blend that also contains eight other ingredients. Even if the entire blend were inulin, the dose would be roughly one seventh of the lowest amount used in the meta-analysis above. A gummy is simply too small to deliver research-level fiber. If you want a prebiotic effect, food sources or a measured inulin powder are more practical.