Fiber is “the new protein,” according to market research firms. But it could also be the new pain in your stomach.
If you’re like most Americans, you’re trying to add more fiber to your diet. That’s a good thing, because the average American gets only half the recommended amount of fiber each day. Manufacturers are responding to consumers’ wishes by adding fiber to a plethora of foods and beverages, including cereals, energy bars, protein supplements, “healthier” cookies, diet ice cream and even bottled water.
One of the most prevalent fiber-boosting ingredients is inulin. Like any fiber, it can cause gas, bloating and abdominal pain if consumed too quickly or in large quantities. Many of my clients who have complained about digestive discomfort don’t realize how much inulin they’re consuming each day. Most of them have never even heard of it.
What is inulin?
Inulin is a type of prebiotic, a substance that’s used by the microorganisms in your digestive tract and positively influences health. At this point, there is evidence that three prebiotics can provide health benefits: inulin, also referred to as long-chain inulin; fructooligosaccharide (FOS), a short-chain inulin that’s also called oligofructose; and galactooligosaccharide (GOS).
Both inulin and FOS are extracted from chicory root fiber, a natural dietary fiber that is extracted using hot water from a plant that’s part of the dandelion family. GOS is produced from lactose, which is sourced from animals. It also isn’t as well-studied as the other two.
Inulin is also found in smaller amounts in whole wheat and some vegetables and fruits, such as asparagus, garlic and bananas.
Longer-chain inulin has a creamy mouthfeel, so it’s often used to help reduce the fat content in products. Short-chain inulin (FOS) tastes slightly sweet, so it’s used to help reduce some of the sugar and sugar substitutes in foods and beverages. Inulin supplements and some foods and beverages will use a blend of short- and longer-chain inulin. These blends are also commonly used in research.
Chicory root fiber passes through your small intestine and then is fermented by the bacteria in your large intestine. As noted above, taking in too much too quickly can lead to digestive discomfort — which can happen with any fiber. In addition, some people seem to be more sensitive to inulin and FOS than others, and may need to limit their consumption.
Inulin does have some digestive benefits. A blend of short- and long-chain inulin has been shown to reduce discomfort and help with constipation. The fiber increases the amounts of beneficial Bifidobacteria and Lactobacilli bacteria in the gut. The European Food Safety Association has approved the claim that consuming at least 12 grams of chicory inulin or FOS a day eases constipation. (There isn’t enough research to state this about GOS.)
Inulin and FOS also may reduce our calorie intake and blood-sugar levels and increase calcium absorption.
Chicory root fiber seems to slow down stomach emptying and suppresses appetite signals in the brain, which could help you eat less. In small studies, adults and children of both normal and excess weight who took a supplement of 12 to 16 grams a day consumed fewer calories.
How Much Inulin to Aim For
Based on research, aim for 5 grams of inulin a day to boost the growth of the probiotic Bifidobacteria in your gut. For better calcium absorption, you want to get 8 grams or more.
Any time you increase your fiber intake, do so gradually to give your body a chance to adjust. Be sure to drink plenty of water to help prevent constipation.
The amount of inulin that’s tolerated seems to vary from person to person. Research suggests that long-chain inulin is better tolerated than FOS. Most healthy people do well with up to 10 grams of inulin and 5 grams of FOS a day.
Companies aren’t required to specify the amount of inulin in their products on the label; it will be included in the total amount of dietary fiber in the Nutrition Facts table. If a food is made with whole grains or other fiber-rich ingredients, such as a cereal or granola bar, it can be tough to tell how much of the fiber is coming from inulin.
If a food or beverage that doesn’t usually contain fiber, such as yogurt or flavored water, lists inulin as the only fiber ingredient, then the amount of dietary fiber tells you how many grams of inulin have been added.
The Bottom Line
Though inulin offers benefits as a fiber source and as a prebiotic, keep in mind that the majority of your fiber should be coming from whole foods that provide other nutrients. The goal is to get 25 to 38 grams of fiber a day from food rather than supplements.
To take in fewer calories, eat plenty of non-starchy vegetables, increase your overall fiber intake via pulses and small portions of whole grains, consume lean protein sources and up your water intake. For better calcium absorption, make sure you’re taking it with vitamin D. Then you can think about whether chicory root fiber is something that could enhance your diet.