Most reviews for Fiber One Chewy bars appear united that the Chicory Root Extract causes great amount of flatulence.
Tasted good but had no idea why I suddenly had such painful and relentless gas. This is not normally an issue with me. When I read the label I didn't see anything that seemed like it would cause such a problem. Then I realized that the first ingredient on the list was something I didn't recognize: Chicory Root Extract. I Googled it and discovered that it is actually a mild laxative and well known for causing terrible gastric issues.
Are these claims exaggerated or is Chicory Root Extract indeed known to cause such symptom?
Chicory root extract is a dietary supplement/food additive which is used as a source of soluble fiber produced by mixing dried, ground chicory root with water. Fresh chicory root contains 68% inulin (fructans), 14% sucrose, 5% cellulose, 6% protein, 4% ash, and 3% other compounds while dried chicory root extract contains approximately 98% inulin (fructans) and 2% other compounds.
Per Brian E. Lacy in 2011, due to absence of large, randomized, controlled studies performed in patients with functional bloating, research data obtained from patients with irritable bowel syndrome show that avoiding food products that readily ferment within the colon such as fructans and fiber improved bloating.
A careful dietary history should be taken from each patient, with an emphasis on food products that readily ferment within the colon (eg, dairy, fructose, fructans, fiber, and sorbitol). A recent study showed that bloating improved in IBS patients who avoided these fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Gastroenterologists usually direct patients to remove one possible offending substance at a time (ie, dairy first, then fructose-containing liquids, then fiber, and so on). Some patients have noted symptom improvement after minimizing carbohydrates and gluten, although this approach has not been well studied.
Chicory contains inulin, a type of fiber classified as a fructan. A large body of research implicates fructans, alongside other carbohydrates that ferment in the colon, in irritable bowel syndrome. The acronym researchers have chosen for this is FODMAPs(fermentable oligosaccharides, disaccharides, monosaccharides and polyols). Mechanisms and efficacy of dietary FODMAP restriction in IBS (Staudacher et al. Nature Reviews Gastroenterology & Hepatology 2014) says:
The inulin-type fructans are a major dietary source of fermentable carbohydrates. They are either linear or branched fructose oligosaccharides that include inulin, (DP 2–60), oligofructose (DP 2–8) and fructo-oligosaccharides (<10 DP).50 Minimal digestion of fructans occurs in the small intestine51 due to the absence of enzymes in the human gastrointestinal tract that are able to digest the β-(2–1) fructosyl–fructose glycosidic bonds.
Fructans are present as storage carbohydrates in plants.52, 53, 54, 55 Most dietary fructans are obtained from wheat and onion,54, 56 which are fairly low in fructans but are consumed in large quantities. Commercial fructans derived from sucrose or chicory root are increasingly added to pre-prepared foods due to their textural and sensory properties and potential health benefits, including their low-energy content.57 Fructans are also prebiotic, as they are “nondigestible, fermentable compounds that lead to selective stimulation of growth and/or activity of one or a limited number of microbial genera/species in the gut microbiota that confer health benefits to the host”
High fiber foods, such as these Fiber One bars, are known to cause excess gas and other intestinal issues. The gas you and others may experience from eating these bars could be due to the high amounts of fiber in each bar. You can read the side of the box, via that Amazon link, to see how much fiber is in each bar (35% DV).
In addition, chicory root is a natural source of inulin, which is also associated with gas/bloating for people.
So not only is chicory root extract a good source of dietary fiber, which is itself associated with digestive side-effects like gas/bloating, it is also a natural source of inulin which is also associated with gas/bloating.
Chicory root extract, like whole grains and beans, is a source of dietary fiber
Chicory root is a natural source of inulin, like garlic and bananas
Sudden increases in fiber is a source of digestive problems
Sudden increases in inulin can be a source of gas/bloating
Reduce negative side effects of dietary fiber and/or inulin-rich foods by increasing them slowly in your diet while your body adjusts
Experts advise drinking extra water to help the fiber pass through the system
SF Gate writes:
Some high-fiber foods may lead to uncomfortable bloating and gas. This
is a natural side effect as the bacteria in your intestinal tract work
to help fiber pass through. Reduce your chances of having gas by
limiting certain types of foods or taking an over-the-counter
supplement to prevent gas.
Consuming too much fiber at one meal or suddenly increasing your fiber
intake may increase uncomfortable gas and bloating in your gut. Reduce
this uncomfortable effect by slowly increasing your fiber intake over
a period of days or weeks. This gives the natural digestive flora in
your gut ample time to adjust to the increase in fiber
Unfortunately, when you start to include more fiber-rich foods in your
diet, you may start to notice an undesirable side effect: excessive
gas. Flatulence and bloating can result, which can be embarrassing and
uncomfortable, to say the least.
If, however, you eat more fiber than you are accustomed to, it can
cause gas and bloating.... Eating a lot of fiber in one sitting, even
if you normally consume a fair amount of fiber, can also cause gas. (emphasis added)
Fiber can cause gas and bloating.... Add fiber gradually over a period of a few weeks to avoid stomach distress. Water helps fiber pass through the digestive system. Drink plenty of fluids (about 8 glasses of water or noncaloric fluid a day).
Experts recommend increasing fiber intake gradually rather than
suddenly, and because fiber absorbs water, beverage intake should be
increased as fiber intake increases.
** Regarding Chicory **
Specifically for chicory root, Wikipedia states that chicory root is a natural source of inulin, which is type of carbohydrate. Extracted chicory root is commonly used by food manufacturers in such things as breakfast bars because of it's smooth texture as a carbohydrate fiber - it's a way to add fiber without changing the taste or texture of the food. Inulin can also be found naturally in bananas, onions, and garlic.
The only problem with inulin may be that it doesn't have the texture or taste of fiber. This can make it easy to consume too much, bringing on the same kind of digestive problems caused by an excess of any fiber: gas/bloating, nausea, flatulence, stomach cramping, diarrhea, constipation and digestive "rumbling."
Inulins are a group of naturally occurring polysaccharides produced by
many types of plants, industrially most often extracted from
chicory.... Inulin-containing foods can be rather gassy, in particular
for those unaccustomed to inulin, and these foods should be consumed
in moderation at first...