Inulin is a carbohydrate and dietary fiber with important health effects. It has a beneficial action on digestive health, regulating bowel habits and relieving both constipation and diarrhea. Inulin is a natural prebiotic which means it feeds good bacteria populations in the colon for better digestion, nutrient absorption and resistance to infection. It stimulates the immune system by boosting the function of several types of white blood cells, regulates blood sugar and cholesterol levels and contributes to diabetes prevention. Inulin is available naturally in root vegetables and as a dietary supplement, but intake should be limited if you suffer from irritable bowel syndrome, Crohn’s disease or other inflammatory bowel conditions.
What is inulin? Inulin is a type of dietary fiber found for the most part in root vegetables and medicinal plants with subterranean stems. It is essentially indigestible plant material that passes unchanged through the digestive tract. Inulin is a type of soluble dietary fiber, meaning it dissolves in water becoming viscous in consistency (similar to pectin). This helps it add bulk to stools and soften them, encouraging more frequent and easy bowel movements and relieving constipation. Moreover, inulin is a natural prebiotic that ferments in the colon and feeds the good gut bacteria, promoting complete digestive health. As a result of its beneficial health effects, it is viewed as a functional food.
What does inulin do? As a dietary fiber, inulin resists digestion, meaning it isn’t absorbed like other nutrients from food. As such, it travels unchanged in the digestive system. It does however absorb water and become viscous, or gel-like, binds to waste material from digested food, forming soft, bulky stools. In the colon, inulin ferments and releases byproducts that cause air and abdominal discomfort for people suffering from irritable bowel syndrome for example. At the same time, it feeds the good bacteria in the lower part of the intestinal tract, which results in digestive and overall health. Healthy gut flora is vital for good health because it determines the amounts of nutrients we absorb from food, inhibits the growth of bad gut bacteria and helps synthesize several essential nutrients such as vitamin K or B12.
Foods rich in inulin
Inulin is present in varying amounts in most root vegetables, edible vegetables with underground stems and the roots and underground stems of some medicinal plants. It is extracted from plant sources to make inulin supplements for more concentrated health effects and to serve as a substitute for fats, flour or sweeteners in the food industry. The best dietary sources of inulin are the following:
1) Chicory root.
2) Burdock root.
3) Dandelion root.
4) Arnica, mountain arnica or wolf’s bane (Arnica montana).
5) Elecampane, Inula or wild sunflower (Inula helenium).
6) Bananas, plantain or cooking bananas.
8) Asparagus and cama bulbs (Camassia).
9) Jerusalem artichoke, globe or green artichoke.
10) Yams, jicama (or Mexican yam bean).
11) Onion, leek, garlic (and the white bulbs in the young plants).
12) Echinacea. For more information on medicinal plants, see my herbs and spices page.
What is inulin good for?
Considering it is a dietary fiber, inulin is primarily good for digestive health. However, studies show it has positive effects on cardiovascular health as well, more exactly on cholesterol levels and blood pressure. The fiber has been found to improve the absorption of certain dietary minerals, regulate blood sugar levels, exert immuno-modulating effects and help with weight loss.
Here are the top 8 properties and health benefits of inulin you get from food sources:
1) Relieves constipation and may hold benefits for diarrhea too. Inulin is apparently good for both constipation and diarrhea because it is a soluble type of dietary fiber. In the digestive system, it adds bulk and softness to stools, promoting more frequent and easy bowel movements. It also binds loose stools, hence its potential benefits for diarrhea as well. Overall, dietary fiber like inulin regulates digestion and transit time.
2) Good for hemorrhoids. Inulin absorbs water while in the digestive system and takes on a more viscous, gel-like consistency which helps make stools softer and easy to pass. This, in turn, is good for hemorrhoids sufferers because it reduces strain during bowel movements, helping control symptoms and manage the condition (read more about what to eat for hemorrhoids).
3) Prebiotic properties. What this means is that inulin ferments in the colon and feeds the good bacteria populations that help maintain gastrointestinal health. This contributes to maintaining healthy populations of good gut bacteria (such as bifidobacteria, lactobacili) which inhibit the growth of bad gut bacteria and offer a certain level of protection against enteric infections.
Moreover, foods that have prebiotic effects also indirectly contribute to boosting the absorption of nutrients at the intestinal level, contributing to good general health. At colon level, inulin also helps reduce inflammation, maintain a thick mucus layer and the overall perfect conditions to protect the colon lining which could mean a lower risk of colon cancer.
4) Boosts immunity. When it ferments in the colon, inulin produces short chain fatty acids that have been shown to directly impact several elements of the immune system. More specifically, studies show inulin intake boost neutrophils, macrophages, T helper cells and NK or natural killer cells function, resulting in improved immune system responses and potentially better protection against infection and disease (Fiber and Prebiotics: Mechanisms and Health Benefits).
5) Cholesterol-lowering properties. As a soluble fiber, inulin has benefits on blood lipids levels, lowering LDL (bad) cholesterol levels. Some studies suggest inulin intake can also decrease blood levels of another fat called triglyceride, contributing to lower total cholesterol levels. This in turn reduces the probability of lipid plaques forming on the inside of artery walls and reducing blood flow, promotes healthy blood pressure levels and reduces the risk of cardiovascular events such as stroke.
6) Inulin and insulin. Multiple studies show inulin reduces blood sugar levels, contributing to better diabetes management and prevention. Moreover, as a dietary fiber, it encourages a healthy body weight, further reducing risks of type 2 diabetes (obesity is a major risk factor for diabetes).
7) Improves calcium and possibly magnesium absorption. Research shows inulin optimizes the absorption of calcium and, in some cases, even magnesium at colon level (Effect of soluble or partly soluble dietary fibres supplementation on absorption and balance of calcium, magnesium, iron and zinc in healthy young men). This appears to be a result of its prebiotic properties which boost populations of healthy bacteria in the colon, improve the health of colon mucosa and its nutrient-absorption components called villi. Optimized calcium and magnesium absorption means better bone density and lower risk of osteopenia and osteoporosis (An inulin-type fructan enhances calcium absorption primarily via an effect on colonic absorption in humans).
8) Inulin for weight loss. Lastly, research shows inulin intake helps maintain a steady and healthy body weight, contributing to benefits such as obesity prevention and diabetes management (Effects of High Performance Inulin Supplementation on Glycemic Control and Antioxidant Status in Women with Type 2 Diabetes).
Side effects and adverse reactions
What are the side effects of inulin? Inulin is basically a type of dietary fiber and is generally considered safe for use, particularly when it is consumed from food sources. However, both dietary inulin and various inulin supplements can have side effects (most likely brought on by excess intakes). Side effects often include loose stools and diarrhea, digestive discomfort, bloating, abdominal pain, cramps, burping and more. The following are conditions that may react badly to a moderate to high intake of the dietary fiber:
1) Gastritis. Fermentation causes air and bloating which can favor the escape of gastric juices in the esophagus and cause acid reflux. Moreover, too much fiber irritates the stomach lining, worsening gastritis symptoms in those with the condition.
2) Irritable bowel syndrome and other inflammatory digestive conditions. Inulin intake can accentuate symptoms of irritable bowel syndrome: bloating, gas, nausea, abdominal cramps, diarrhea, even constipation.
3) Interfere with nutrient and medicine absorption. All types of dietary fiber reduce or increase the absorption of various nutrients and medicines. Inulin too may has such effects which is why it is recommended to take your medicines or vitamin and mineral supplements two hours before you take inulin or four hours after. Consult your doctor for more information on the interactions and contraindications of inulin supplementation.
Sensitivities and intolerance
Inulin is a type of soluble dietary fiber known as a fructan, meaning it’s made of larger molecules of fructose (a naturally occurring sugar). In the colon, it is fermented rapidly. While this is beneficial for gut bacteria populations, it is also a source of gastrointestinal discomfort in particularly sensitive individuals who cannot digest fructans properly. Those sensitive or even intolerant to fructans are advised to go on a low-FOODMAP diet, excluding potentially problematic foods such as chicory root, dandelion root and leaves, green artichoke, Jerusalem artichoke, the bulbous part of onions, garlic and leek as well as grains such as wheat, barley, rye.
The important thing to remember about inulin is that it is a soluble dietary fiber with both benefits and side effects. Inulin in the amounts consumed from dietary sources dissolves in water and ferments in the colon, producing benefits for constipation, diarrhea and gut flora, augment overall digestive health. Its beneficial effects extend to include cholesterol-lowering properties, blood sugar-regulating activity, immune system-strengthening action and improving calcium and possibly magnesium absorption. However, too much inulin, either from dietary sources or food supplements, is bad for irritable bowel syndrome, gastritis, inflammatory digestive conditions and can impact the absorption of certain medication and essential nutrients.