We're all aware of how vital a fiber-rich diet is for heart health, digestive health, bowel movements, and more. But did you know that specific types of fibers have benefits beyond what we typically think about fiber?
One, in particular, called inulin, is a type of fiber touted for its beneficial role in gut and metabolic health, besides the typical roles in digestive health.
Although there are several types of inulin, they all have one thing in common: their ability to act like prebiotic fiber. Never heard of it?
Nope, it's not the conventional probiotics we hear about all over the health news. They're a dietary fiber that serves as food for the beneficial bacteria in your gut. Because it can't be broken down or absorbed in the GI tract, it offers body-wide benefits.
The same goes for inulin—because humans don't possess the enzymes needed to break it down, it passes through the digestive tract intact and feeds the good gut bugs (these guys are the probiotics) while offering other benefits such as lowering cholesterol and promoting satiety. Sounds like a real winner, right?
So, if you're unfamiliar with inulin, you're in the right place. This article explains what you need to know about the prebiotic fiber inulin and how it supports gut health (and overall full-body health).
What Is Inulin?
At first glance, you may think we're talking about insulin, but we're not. Inulin is a soluble plant fiber found in high amounts in thousands of plant species, especially chicory root.
You'll also find it in things like bananas, onions, garlic, asparagus, and Jerusalem artichokes—all foods we call prebiotic foods.
As a prebiotic fiber, humans don't possess the enzymes necessary to break it down, so it travels through the digestive system relatively untouched.
While you may think, "what's the point of eating something that's not going to be absorbed?" we get it—but there are plenty of benefits.
Dietary fibers like inulin have been consumed for hundreds of years to improve bowel regularity, digestive health, and heart health. And best of all, it's completely natural!
On a technical level, inulin is a type of fructan, oligofructose carbohydrate 1. It's naturally present in plant roots and stems as a source of energy.
And although you may not think about fiber as a source of sugar, it is—and it contains about 75% fewer calories than white sugar per gram and has minimal effect on blood glucose, making it a good option for people with diabetes and those with glucose imbalances. Because of its osmotically active properties, it resists breakdown by digestive enzymes.
Of the bacterial species that utilize prebiotics, inulin-type fructans have a specific colonic fermentation directed toward bifidobacteria, which can break down and use inulin-type fructans as a result of possessing the fructofuranosidase enzyme 2. So, they have a competitive advantage in a mixed species environment such as the gut.
But what's so good about inulin? Studies show that inulin is essential for human health because of its "prebiotic effect," meaning it allows the healthy bacterial species (probiotics) that make up the gut (microbiome) to thrive and proliferate 3. But it also binds to cholesterol, which can reduce levels and the associated risk of metabolic syndrome.
Related Post: Should I Take Prebiotic Fiber Before or After a Meal?
Inuline vs Psyllium: What's The Difference Between Them?
Apart from inulin, there's another soluble fiber we commonly hear about, psyllium husk. As the name suggests, psyllium husk is extracted from the husks of the Plantago ovata plant's seeds.
For anyone looking to improve digestion and cholesterol levels, it's considered gold 4. It's the backbone of most fiber supplements and many high-fiber snacks.
Compared to inulin and other fiber supplements, psyllium absorbs more water. It is less fermentable in the gut, which means it expands and becomes sticky when consumed, helping keep bowel movements regular, preventing constipation, and improving diarrhea.
Because inulin doesn't absorb water to the same capacity, it doesn't have the same laxative effect.
Inulin And Health: The 5 Benefits You Need To Know About
1. Relieves and reduces constipation
Backed up? Although there are several causes of constipation, not consuming enough dietary fiber is a big one—and inulin is excellent for supporting that.
Because of its chemical composition, inulin forms a gel-like substance that is great for getting the bowels moving. When it forms a gel, it has a structure similar to fats that lubricate the GI tract and reduce the risk of things like hemorrhoids.
On top of bulking up stools and increasing fecal biomass and water content, it also helps to improve bowel movement frequency because it rapidly ferments in the colon to feed the beneficial bacteria 5, 6.
A 2017 study published in the International Journal of Food Sciences and Nutrition found that supplementation with 4g of Orafti® Inulin three times daily in chronically constipated adults significantly improved bowel function compared to placebo 7.
2. Supports beneficial bacteria in the gut
Because inulin is a non-digestible prebiotic fiber, it passes through the GI tract relatively intact and unabsorbed. As it passes, it naturally starts to ferment, providing food for the beneficial bacterial species that populate the gut, especially Bifidobacterium.
Studies show that oligofructose acts like a prebiotic to enhance the lining of the gut and colon, alter the biodiversity of the gut, and modulate the endocrine and immune functions 8.
Because it promotes the growth and proliferation of healthy bacteria, it may also reduce the presence of potentially harmful ones that cause inflammation.
Related Post: Inulin and IBS: What's The Link?
3. Reduces appetite
If you struggle with weight loss, adding some prebiotic fiber to your diet may help, thanks to its low-calorie content and absorbability.
When inulin combines with water, it provides bulk and creates a gel-like substance that expands and increases the size of the contents in the digestive tract. As such, it can reduce appetite and cravings, making inulin a solid option for weight loss.
Prebiotic fibers also help delay gastric emptying and take up more space in the stomach, thereby promoting satiety and helping reduce energy intake 9.
4. Improves heart health and reduces metabolic syndrome risk factors
There are ample ways to improve heart health naturally, but did you know fiber can do so, too? When inulin passes through the Gi tract, it picks up toxins, tastes, fat, and cholesterol, helping with their excretion—this is why high-fiber diets are often linked to improved cardiovascular outcomes 10.
Studies find that boosting your fiber intake can help reduce blood cholesterol levels, reduce arteriosclerosis risk, and maintain healthy glucose levels 11.
How is this possible? There's an inverse relationship between dietary fiber content and systolic and diastolic blood pressure, total cholesterol levels, and triglycerides. Simply put, soluble fiber helps reduce LDL cholesterol b blocking its absorption.
Need more?
Inulin also won't increase your blood glucose levels! Since it's not metabolized in the body, it doesn't trigger insulin release and a spike in blood sugar 12.
5. Enhances calcium absorption
Although not directly related to gut health, calcium is essential for many physiological functions in the body, including bone and muscle health. Some research shows that bumping your fiber intake could improve the absorption of specific minerals, such as calcium and magnesium 13. How does fiber support nutrient absorption? You can thank its prebiotic effect on the gut.
A 2005 study published in the American Journal of Clinical Nutrition looked at the effects of inulin-type fructans supplementation on calcium absorption and bone mineral accretion in pubertal adolescents 13.
They found that daily supplementation with prebiotic short- and long-chain inulin-type fructans resulted in significant increases in calcium absorption and greater bone mineralization during periods of pubertal growth.
As such, in populations susceptible to calcium deficiency—young females and post-menopausal women—inulin supplementation may be beneficial for enhancing calcium absorption and supporting bone health.
Takeaway message: Based on what we just talked about, the benefits of soluble fiber extend far beyond just the gut. Here's a list of the benefits of inulin-type prebiotics:
- Improves gastrointestinal and gut health
- May prevent certain chronic diseases
- Improves blood sugar control and protects against type 2 diabetes
- Supports growth and development in kids
- Improves cholesterol levels and lipid metabolism
- Improves bone mineralization
- May reduce the risk of obesity
- Enhances immunity
Where To Find Inulin
Although inulin is easily found in supplemental form, it's also widely available in many plant foods—they're what we call prebiotic foods! Try adding some of these to your diet to boost your inulin intake:
- Chicory root fiber
- Dandelion root
- Asparagus
- Leeks
- Onions
- Bananas
- Plantains
- Sprouted wheat
- Garlic
- Fresh herbs
- Yams
- Jerusalem artichokes
- Burdock root
- Echinacea
- Jicama
- Yacon root
Dietary fibers are the primary food source for the good bugs in your gut, which is why we promote a diet rich in fruits, leafy green vegetables, beans, and legumes.
But if you're looking to increase your intake further, consider something like Performance Lab Prebiotic—it's a 2-in-1 soluble fiber and prebiotic supplement designed for full-spectrum microbiome support.
Unlike conventional probiotics that introduce new colonies into the gut, Prebiotic nourishes those that already exist for digestive comfort and peace of mind.
How Much Inulin Do You Need?
There's no definitive amount of inulin to support gut health, but it can be consumed as part of your daily fiber intake. Based on archaeological evidence, ancient populations thriving on a primarily plant-based diet consumed around 135 grams of prebiotic inulin-type fructans daily 14.
Although it's hard to estimate exactly how much the average adult consumes—it varies considerably based on diet—most Americans consume far less than the recommended daily fiber intake, around 10-15 grams, from fruits, vegetables, and processed foods with added chicory root 15.
On average, adults should consume 20-35 grams of fiber daily from whole food sources. But because inulin is easily added to foods like oatmeal, juices, and baked goods without influencing their taste, it's easy to increase your intake!
Generally speaking, start with 3-5 grams of inulin per day and work your way up to a daily dose between 5 and 15 grams for optimal benefits.
References
- Kolida S, Gibson GR. Prebiotic capacity of inulin-type fructans. J Nutr. 2007;137(11 Suppl):2503S-2506S.
- Playne MJ, Crittenden R. Commercially available oligosaccharides. Bull Int Dairy J. 1996;313:10-22.
- Vandeputte D, Falony G, Vieira-Silva S, et al. Prebiotic inulin-type fructans induce specific changes in the human gut microbiota. 2017;66(11):1968-1974.
- Fischer MH, Yu N, Gray GR, Ralph J, Anderson L, Marlett JA. The gel-forming polysaccharide of psyllium husk (Plantago ovata Forsk). Carbohydr Res. 2004;339(11):2009-2017.
- Den Hond E, Geypens B, Ghoos Y. Effect of high performance chicory inulin on constipation. Nutrition Research. 2000; 20(5):731-736.
- Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews . York (UK): Centre for Reviews and Dissemination (UK); 1995-. Effectiveness of inulin intake on indicators of chronic constipation; a meta-analysis of controlled randomized clinical trials. 2014. Available from: https://www.ncbi.nlm.nih.gov/books/NBK291126/
- Micka A, Siepelmeyer A, Holz A, Theis S, Schön C. Effect of consumption of chicory inulin on bowel function in healthy subjects with constipation: a randomized, double-blind, placebo-controlled trial. Int J Food Sci Nutr. 2017;68(1):82-89.
- Roberfroid MB. Introducing inulin-type fructans. Br J Nutr. 2005;93 Suppl 1:S13-S25.
- Hume MP, Nicolucci AC, Reimer RA. Prebiotic supplementation improves appetite control in children with overweight and obesity: a randomized controlled trial. Am J Clin Nutr. 2017;105(4):790-799.
- Anderson JW, Smith BM, Gustafson NJ. Health benefits and practical aspects of high-fiber diets. Am J Clin Nutr. 1994;59(5 Suppl):1242S-1247S.
- Brown L, Rosner B, Willett WW, Sacks FM. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Am J Clin Nutr. 1999;69(1):30-42.
- Niness KR. Inulin and oligofructose: what are they?. J Nutr. 1999;129(7 Suppl):1402S-6S.
- Abrams SA, Griffin IJ, Hawthorne KM, et al. A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents. Am J Clin Nutr. 2005;82(2):471-476.
- Leach JD, Sobolik KD. High dietary intake of prebiotic inulin-type fructans in the prehistoric Chihuahuan Desert. Br J Nutr. 2010;103(11):1558-1561.
- Quagliani D, Felt-Gunderson P. Closing America's Fiber Intake Gap: Communication Strategies From a Food and Fiber Summit. Am J Lifestyle Med. 2016;11(1):80-85.
