The Specific Carbohydrate Diet

Frequently Asked Questions


Seth writes:

Inulin is an FOS.

We have a good page on FOS/inulin:

It is on the bottom of this page:

Making a Case Against FOS and Inulin

Have you heard about Fructo-oligosaccharides (FOS) or Inulin yet? If not, you will. These are the latest and greatest refined chemicals that probiotic and yogurt manufacturers are adding to their products for "your health". It seems that only a few probiotic manufacturers are against using them, with Natren leading the charge. But we like to ask, why is this? Why would Natren be against using FOS in yogurt and probiotic supplements? What kind of financial gain is involved in not using the latest and greatest chemicals in your products? None that we could think of. So we decided to investigate this matter further.

1. What is FOS and Inulin?

Fructo-oligosaccharides (FOS) and inulin are types of fructo-polysaccharides, comprised of -(glucose-fructose)- subunits. The only difference between FOS and inulin is polymer chain length. Inulin/FOS also goes by the name of Neosugar, Alant Starch, Atlanta Starch, Alantin, Dahlin, Helenin, and Diabetic Sugar. Inulin tastes sweet, cannot be digested by humans, and is soluble (unlike cellulose).

2. What does Inulin/FOS do?

Since Inulin/FOS is indigestible by our bodies, it gets transported to the large intestine where it feeds microbes and promotes fermentation. Inulin/FOS has been dubbed a "prebiotic", essentially serving as fertilizer for the bacteria in your colon. Certain lactobacillus species of bacteria have been shown to preferentially ferment Inulin/FOS. For this reason, it is being promoted as a supplement to feed the good bacteria in our guts.

3. Inulin/FOS feeds only good bacteria, right?

Wrong. Manufacturers claim that Inulin/FOS specifically feeds only good bacteria. The reality of the situation is much different. If you examine the scientific literature about Inulin/FOS, you will find that this is untrue. The best example is concerning Klebsiella. Recent studies have shown that Inulin/FOS encourages the growth of Klebsiella, a bacterium implicated in Ankylosing Spondylitis and increased intestinal permeability. Inulin/FOS may indeed promote the growth of lactobacillus bacteria, but what other potentially harmful bacteria are we feeding as well? Furthermore, we have not even addressed the issue of yeast. Many different species of yeast are able to utilize Inulin/FOS for energy.

Historically, microbes have demonstrated the innate ability to adapt to almost any condition and fuel source. If bacteria can adapt to break down industrial solvents in our soil and use them for energy, it would be irresponible to think that they will not adapt to utilize Inulin/FOS, a high energy carbohydrate. There are hundreds of different species of bacteria and several yeast strains living in our GI tracts. Studies have only looked at the effects of Inulin/FOS on a handful of these microbes.

4. Why is Inulin/FOS being added to probiotic supplements and yogurt?

A key principle in today's marketplace is product differentiation. If a manufacturer can sell many different kinds of "specialty" products, that are in essence the same thing, it can make a larger profit. Think about it for a moment. We no longer have plain old toothpaste, instead we have such items as tartar control, sensitive, baking soda, peroxide, whitening, gum care, and many others. Adding a new claim to an old product adds to consumer excitement: "Brand X yogurt - now with Inulin/FOS for your health" & "We now offer lactobacillus capsules with Inulin/FOS." These new claims will help fight market stagnation and lead to greater profits for the manufacturer. But will FOS lead to greater health for the consumer?

5. Is Inulin/FOS found naturally anywhere?

Yes. It is found naturally in asparagus, garlic, Jerusalem Artichokes, chicory root, and others.

6. Since Inulin/FOS is found in natural foods it must be okay, right?

Wrong. Sucrose (table sugar) is naturally found in beets, sugar cane, oranges, and other plants. Humans have perverted this naturally occurring substance into a refined chemical. Sucrose is arguably one of the most unhealthy food additives in human history. We should learn from our experiences with sucrose and apply them to Inulin/FOS. Instead of adding refined, super concentrated Inulin/FOS to your food, eat the foods that naturally contain Inulin/FOS.

The body is genetically adapted to certain foods and if we continue to mess with our food chain then our health will suffer the consequences. Of the nutritional fibers, cellulose was the most likely to be included in a traditional hunter-gatherer diet. Cellulose is an insoluble fiber that is slowly fermented by the microbial population in the human colon. Inulin/FOS is a soluble fiber that is quickly and easily fermented. The difference between cellulose (a food we are adapted to) and Inulin/FOS (a food we are not adapted to) is like the difference between a slow burning ember and a raging fire. Who likes playing with fire?

7. Is it possible to be allergic to Inulin/FOS?

Yes. In one documented case, inulin caused an anaphylactic reaction. As the use of Inulin/FOS as an additive in the food industry increases, reports of allergic responses will probably increase. "Inulin may be the culprit behind more food allergies than is currently recognized."

8. What are the recognized side effects of ingesting Inulin/FOS?

Assuming one is not allergic to Inulin/FOS, the typical side effects will vary depending on one's level of tolerance. The list of known side effects include: flatulence, bloating, cramps, abdominal pain, and diarrhea. As Inluin/FOS permeates our food supply, the list of side effects is expected to grow.

Conclusion -

In theory, a food additive that could specifically feed good bacteria might prove useful for intestinal health. Given the nature of the microbes and their ability to quickly adapt to various carbohydrate foods sources, it seems highly unlikely that such a chemical will be developed. Inlulin/FOS has been touted as such a molecule, but seems to fail the test as you examine it further. Even if Inluin/FOS did display specifity for beneficial bacteria, do we know enough about the complex microbial ecology of the human GI tract to deem a species of bacteria better than the others? The GI tract is much like a rain forest with a very complex web of life. What would happen to a rain forest if, in our arrogance, we decided to spread a chemical that fertilized one specific type of tree? Would the overgrowth of one species be beneficial? Our GI tracts have adapted to house a variety of microbes and to disrupt this balance might be detrimental to our health. With these concerns, we recommend staying far away from any product with Inulin/FOS.


Green, Ceri J. Fibre in Enteral nutrition, S A J Clin Nutr 2000 November Vol 13 No 4

Nutritional and health benefits of inulin and oligofructose: proceedings of a conference, Bethesda, Maryland, USA, May 18-19, 1998. J Nutr 1999;129:Suppl:1395S-1502S.

Coussement PAA. Inulin and Oligofructose: Safe Intakes and Legal Status J. Nutr. 1999 129: 1412

Gibson GR; Beatty ER; Wang X; Cummings JH. Selective stimulation of bifidobacteria in the human colon by oligofructose and inulin. Gastroenterology, 1995 Apr, 108:4, 975-82

Ingeborg M. Bovee-Oudenhoven, Mischa L. Wissink, Jan T. Wouters, and Roelof Van der Meer Dietary Calcium Phosphate Stimulates Intestinal Lactobacilli and Decreases the Severity of a Salmonella Infection in Rats J. Nutr. 1999 129: 607-612.

Lin Meei-yn and Chung-ming Young. Biosynthesis of Folates by Streptococcus thermophilus and Lactobacillus delbruekii ssp. bulgaricus. Journal of Food and Drug Analysis, Vol. 8, No. 3, 2000, Pages 195-199

Niness KR. Inulin and oligofructose what are they? J Nutr 1999 Jul;129(7 Suppl)1402S-6S

Marshall VM & Cole WM (1985): Methods for making kefir and fermented milks based on kefir. J. Dairy Res. 52, 451-456.

Mitsuoka T, Hidaka H, Eida T. Effect of fructo-oligosaccharides on intestinal microflora. Nahrung 1987;31:427-436.

Roberfroid M. Dietary fiber, inulin, and oligofructose: a review comparing their physiological effects. Crit Rev Food Sci 1993,33(2):103-48

Valyshev AV, Kirillov VA, Kirillov DA, Bukharin OV. The effect of inulin on the biological properties of enterobacteria. Zh Mikrobiol Epidemiol Immunobiol. 2000 Jan-Feb;(1)79-80.

Van de Water J., Carl L. Keen, and M. Eric Gershwin The Influence of Chronic Yogurt Consumption on Immunity J. Nutr. 1999 129: 1492

Wang X, Gibson GR. Effects of the in vitro fermentation of oligofructose and inulin by bacteria growing in the human large intestine. J Appl Bacteriol 1993 Oct;75(4):373-380

Back to SCD Frequently Asked Questions - Table of Contents

"We must never forget that what the patient takes beyond his ability to digest does harm."
    Dr. Samuel Gee

Back to PecanBread