FOS and Inulin (pre-biotics)

last updated 8.25.05

There is mixed philosophy on the issue of FOS, inulin, and other things called 'prebiotics'. FOS is short for fructo-oligosaccharides. Here are some links telling more about it:

Link 1
Link 2
Link 3

The basic idea is that these are natually occuring sugars that are bound in such a way that animals, including humans, cannot digest them. However, certain bacteria can - not all bacteria, only some. Ruminants such as cows can process these because of the bacteria in their 4 stomachs and colon region. Human only have one stomach and pre-biotics are not digested in them. Prebiotics are not digested or absorbed in the small intestine either according to studies (although maybe in some scenarios bacteria in the small intestine might).

However, the bacteria that reside in the colon can digest them and put them to good use, such as bifidus. So for good colon health, B vitamin production and other things, FOS or inulin has proven very beneficial. Thus, some probiotics contain the beneficial bacteria and FOS/inulin in one capsule so there is a selective food supply for the probiotic right there, helping it to get a good rapid jump on colonizing and growing in the colon. Below is a more lenthy desciption that I found helpful and not excessively technical:

This link outlines some of the arguments in a rather animated way. Research included:

Okay, so if FOS/inulin is so wonderful, what about Mandi's experience that FOS was bad and SCD (Specific Carbohydrate Diet) doesn't care for it? This is probably not a contradiction. Probably depends on the situation and the exact problem in the person at a particular point in time. There are more choices besides:
1 - FOS is crystalized poison and always bad
2 - FOS is natures blessing upon us and always good

What I read from all this is that if you have a *really bad* bacteria problem (the condition of most of those doing SCD), then probably best to hold the FOS/Inulin because you have so much more bad bacteria.

If you are in moderate to good gut health, FOS/Inulin is probably very beneficial and helps you maintain a good microflora, maximizing the effectiveness of whatever probiotics are there (or consumed).

An agriculture analogy: If you have a really weedy lawn, and you throw lots of seed and fertilizer on it, the weeds are so far ahead of the grass seed and so well established, the little grass seeds can't get started very well. The weeds are able to use some of the fertilizer for themselves.

So you need have a blast of weedkiller of some kind to really whack out the weeds. THEN you add grass seed and lots of fertilizer and the grass seed has a chance to outcompete the weeds. The grass noticeably benefits from the fertilizer.

Depends on the conditions you have. Might be very good, might be not-so-good. Might be good to avoid until there is more gut healing and then add it.

Also check on the strain of bacteria you are looking at, both in terms of the adverse strain(s) you are wanted to control and the beneificial strains in your probiotic. Some strains can metabolize FOS and other cannot. This may influence your decision and results with FOS.

There seems to be a very wide range of what is recommended for FOS and inulin too. For example, a few milligrams in a probiotic supplement is very different from the 5-15 grams or more recommended on some FOS/inulin products. In one case it is a 'token' amount but in another you are flooding your system with it. One scenario may work for one person but the other one may be better for someone else.

This appears to be two different strategies, and both may work if you pick a strategy and carry it through. On the label of a product called Inulation by Thropps Nutrition, it even suggests 5-15 grams per day, and up to 40 grams of FOS daily for geriatrics. The idea is to flood the system with a substance that helps promote the beneficial probiotics in your system to outcompete the harmful ones. This product is specifically for IBS and colon problems.

It appears to me that SCD (also for celiac, colon problems, IBS) has a totally opposite strategy than this Inulation, or the standard recommendation of high fiber diets for colon problems. In fact SCD about does away with any and everything that other treatments for colon problems recommend (and there are also many testimonials and studies showing these other methods also helped some people with colon problems). So who is correct? Probably both to some extent. The idea is to pick one, try it. If not, try the opposite one and stick with that one for a designated time. It also may not be possible to do one, so you have other alternatives at hand.


Update: Here is a study found showing how the addition of FOS significantly improved digestive enzyme activity in the gut, improved probiotic colonizations, and improved some parameters of gut health in poultry:

Effects of dietary fructooligosaccharide on digestive enzyme activities, intestinal microflora and morphology of male broilers.

Poult Sci. 2003 Jun;82(6):1030-6. PMID: 12817461 [PubMed - indexed for MEDLINE]

Xu ZR, Hu CH, Xia MS, Zhan XA, Wang MQ. Zhejiang University, Animal Science College, Key Laboratory of Molecular Animal Nutrition, Ministry of Education, HangZhou, 310029, P. R. China.

Two hundred forty male Avian Farms broiler chicks, 1 d of age, were randomly allocated to four treatments, each of which had five pens of 12 chicks per pen. The chicks were used to investigate the effects of fructooligosaccharide (FOS) on digestive enzyme activities and intestinal microflora and morphology. The chicks received the same basal diet based on corn-soybean meal, and FOS was added to the basal diet at 0, 2.0, 4.0, and 8.0 g/kg diet at the expense of corn. Addition of 4.0 g/kg FOS to the basal diet significantly increased average daily gain of broilers. The feed-to-gain ratios were significantly decreased for the birds fed diets with 2.0 and 4.0 g/kg FOS versus the control. Addition of 4.0 g/kg FOS enhanced the growth of Bifidobacterium and Lactobacillus, but inhibited Escherichia coli in the small intestinal and cecal digesta. Supplementation of 2.0 or 4.0 g/kg FOS to chicks significantly improved the activities of amylase compared to the control (12.80 or 14.75 vs. 8.42 Somogyi units). A significant increase in the activities of total protease was observed in 4.0 g/kg FOS-treated birds versus controls (83.91 vs. 65.97 units). Morphology data for the duodenum, jejunum, and ileum showed no significant differences for villus height, crypt depth, or microvillus height at the duodenum. By contrast, addition of 4.0 g/kg FOS significantly increased ileal villus height, jejunal and ileal microvillus height, and villus-height-to-crypt-depth ratios at the jejunum and ileum and decreased crypt depth at the jejunum and ileum. However, addition of 8.0 g/kg FOS had no significant effect on growth performance, digestive enzyme activities, intestinal microflora, or morphology.





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