Side Effects of FOS in Probiotics
In recent years, yogurt and kefir have become popular foods because of the medical community's acknowledgment of the benefits of probiotics found in these foods. Probiotics are simply "good bacteria," and probiotic-containing foods can help increase the levels of these bacteria in the gut and decrease harmful microbes, creating a healthier internal environment. A more recent development of probiotic-laden foods such as yogurt is the addition of certain "prebiotics," which are added components that help the good bacteria thrive. They basically serve as food for the beneficial bacteria. FOS is considered a prebiotic.
What Is FOS?
FOS stands for fructo-oligosaccharides, and these sugars linked together in chain formation. Inulin is a popular version of an FOS that is often added to foods with probiotics and is also marketed under the names Neosugar, Alant Starch, Atlanta Starch, Alantin, Dahlin, Helenin and Diabetic Sugar. FOS is found naturally in certain foods, such as asparagus, garlic, Jerusalem artichokes and chicory root.
While simple sugars are digested by your body, FOS is mostly indigestible because humans don't have the enzymes needed to break it down, and so it functions as fiber in the diet. When FOS reaches the large intestine, some of the bacteria that reside there there do have the necessary enzymes and can begin breaking down the FOS and using the components as their own food. The beneficial Bifidobacterium have been reported to use FOS in this way. In this case, FOS acts almost like a fertilizer for certain strains of gut bacteria.
- FOS stands for fructo-oligosaccharides, and these sugars linked together in chain formation.
- In this case, FOS acts almost like a fertilizer for certain strains of gut bacteria.
Why Is There Concern About This Ingredient?
List of Good Bacteria
The research is quite mixed on FOS, with many studies showing seemingly opposing results. While there is definitely strong support showing that FOS does indeed foster Bifidobacterium colony growth, it could also serve as food for less desirable strains of bacteria. Some studies have indicated that inulin encourages the growth of Klebsiella, a bacterium at work in Ankylosing Spondylitis, which causes problems with intestinal permeability. It also feeds E. coli and many Clostridium species, which are inharmonious with gut-friendly bacteria. There is also a concern that some kinds of yeast are able to use inulin/FOS for fuel, thereby possibly leading to overactive yeast production in the body.
Of additional concern is that many microbes are able to adapt to almost any environment and energy source. Some bacteria were shown to be able to break down and use industrial solvents in the soil. This is not their normal food source, but they adapted and utilized what was available to them. There is concern that "bad" bacteria and fungi could begin to use FOS as a fuel source. Scientists do not fully understand the complex interactions between all the microbes in our bodies, and disrupting the natural balance is concerning. As with any ingredient, there is also potential for allergic reaction; indeed, there is one documented case of inulin causing an anaphylactic reaction.
- The research is quite mixed on FOS, with many studies showing seemingly opposing results.
- There is also a concern that some kinds of yeast are able to use inulin/FOS for fuel, thereby possibly leading to overactive yeast production in the body.
Reported Side Effects
The list of reported side effects with FOS consumption include flatulence, bloating, cramps, abdominal discomfort and pain, and diarrhea, especially when taken at doses of 15 grams or more per day. Those with lactose intolerance may experience more of these side effects. The byproducts of fermentation of FOS are hydrogen and carbon dioxide, which are the gases that can cause these uncomfortable symptoms. Adjusting the amount you ingest may alleviate some of the symptoms.
- The list of reported side effects with FOS consumption include flatulence, bloating, cramps, abdominal discomfort and pain, and diarrhea, especially when taken at doses of 15 grams or more per day.
- The byproducts of fermentation of FOS are hydrogen and carbon dioxide, which are the gases that can cause these uncomfortable symptoms.
List of Good Bacteria
Are There Probiotics in Sour Cream?
Food With Lactobacillus
Inulin Fiber Side Effects
Side Effects of Zymex
Different Types of Probiotics for Body Odor
Almonds & Digestion
Kefir & the Atkins Diet
Can Certain Foods Kill Intestinal Parasites?
- Health Library: Fructo-oligosaccharides (FOS)
- PDR Health: Fructo-Oligosaccharides
- Medicinal Food News: Fructooligosaccharides - FOS
- Nutrition Journal: Short Chain Fructo-oligosaccharides
- Journal of Nutrition: Prolonged Intake of Fructo-Oligosaccharides
- Gut Bacteria in Health and Disease
- Probiotics and Colon Cancer
- Influence of High-Fat-Diet on Gut Microbiota: A Driving Force for Chronic Disease Risk
- Adaptation of the Gut Microbiota to Modern Dietary Sugars and Sweeteners | Advances in Nutrition | Oxford Academic
- Influence of diet on the gut microbiome and implications for human health
- Connection Between BMI-Related Plasma Metabolite Profile and Gut Microbiota - PubMed
- Organophosphorus pesticide chlorpyrifos intake promotes obesity and insulin resistance through impacting gut and gut microbiota | Microbiome | Full Text
- Food Chemicals Disrupt Human Gut Microbiota Activity And Impact Intestinal Homeostasis As Revealed By In Vitro Systems | Scientific Reports
- Looking at the Effects of Antibiotic Use on Childhood Obesity and Growth -- The PCORnet® Antibiotics Study | PCORI
- Associations of Prenatal and Childhood Antibiotic Use with Child Body Mass Index at Age Three Years
- Dynamics of Human Gut Microbiota and Short-Chain Fatty Acids in Response to Dietary Interventions with Three Fermentable Fibers | mBio
- Commercial Probiotic Products: A Call for Improved Quality Control. A Position Paper by the ESPGHAN Working Group for Probiotics and Prebiotics - PubMed
- Frontiers | Probiotic Supplements: Hope or Hype? | Microbiology
- Choosing an appropriate probiotic product for your patient: An evidence-based practical guide
- A review of probiotic supplementation in healthy adults: helpful or hype? - PubMed
Paul Elsass started writing in 1986. He has written articles for the Clinical Exercise Physiology Association and multiple medical-fitness centers. Elsass has certifications through the American College of Sports Medicine and the American Council on Exercise. He holds a Bachelor of Science in Kinesiology from the University of Texas and a Master of Science in Management from Northern Arizona University.