What Are Prebiotics? - Natren, Inc.

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What Are Prebiotics?


Natasha Trenev is the Founder and President of Natren Inc, Chairwoman of The Global Institute of Probiotics, a renowned author, host of TV and radio shows, and a guest lecturer at leading universities. As a probiotic scholar, developmental scientist, researcher, educator, and health advocate, she has surpassed her centuries-old family tradition of culturing custom probiotics. She is now leading the scientific community in the acquisition of knowledge about probiotic products, probiotic benefits, and their applications for improved human health. Natren and Natasha are devoted to passing along that knowledge to the general public.


Natren probiotic supplements have never contained prebiotics. Two common commercially available forms of prebiotics are inulin* and fructooligosaccharide (FOS)*.

Prebiotics are a class of simple carbohydrates found naturally in plants like Jerusalem artichokes, chicory and onions. Most of the prebiotic inulin or prebiotic fructooligosaccharide commercially available on the industrial market is either synthesized from sucrose or extracted from chicory crops. Inulin and FOS can be obtained from the sliced plant through a hot water extraction process**. Fructooligosaccharide can also be manufactured through chemical synthesis, using a fungal enzyme to convert cane or beet sugar into FOS.1

Inulin and fructooligosaccharide are non-digestible food ingredients that selectively stimulate the growth or activity of one or a limited number of bacterial species already present in the colon.2 However, current research strongly indicates that careful analysis of the effects of prebiotics on the total bacterial community is required, rather than analyzing prebiotic effects on just a selected few.3


Prebiotics change the metabolic activity of the colon through selective fermentation by resident bacterial species. Abnormal functions may occur as a result.4 Researchers from the University of Helsinki and the University of Montana studied mice fed with inulin prebiotic diets, and discovered shifts in the total bacterial community, including the discovery of previously unknown bacterial strains. There were significant chemical changes with higher levels of residual lactic acid.3 Other studies have reported increased potential for intestinal tumors and colon cancer in mice fed inulin supplemented diets. These studies strongly suggest a negative aspect to the use of inulin as a prebiotic.5 6 7


The safety of the use of oligosaccharides is at issue. Fructooligosaccharide and inulin influence many aspects of bowel function through fermentation. Consumption of FOS causes rapid fermentation in the colon and produces adverse effects such as fullness (bloating), abdominal pain, meteorism (production of large amounts of gas) and the production of loose stools.4 8

Fructooligosaccharide stimulates the growth of the pathogenic (capable of causing disease) bacteria species Klebsiella pneumoniae, and possibly other pathogenic organisms.9 Researchers have found an association between K. pneumoniae and the autoimmune disease known as ankylosing spondylitis.10 11 12 Klebsiella has been identified as one of the "big three" gram-negative pathogenic bacteria with growing antibiotic resistance in the United States and abroad. 13


Some types of FOS are derived from cane or beet sugar. Probiotic supplements help the body maintain proper levels of yeast. Since yeast use sugar and sugar derivatives as a food source, why would anyone take a supplement that contains a sugar derivative? Fructooligosaccharide could easily influence the growth of yeast, counteracting any probiotic benefits the supplements might provide.14 15 16


All Natren probiotic products have been formulated to retain the supernatant.

Prebiotics are bacteria species specific as well as bacteria strain specific, and not all beneficial bacteria are compatible with oligosaccharides.3 4 Since the supernatant already provides specifically designed food for the good bacteria in Natren probiotics, there is no need to add fillers such as FOS or inulin.

Natren has taken a strong stand against the use of prebiotics such as fructooligosaccharide or inulin in probiotic supplements since we introduced our own line of products in the early 1980s. Our position on prebiotics and probiotics has not changed since then.

Natren has chosen not to combine prebiotics and probiotics in its products for these reasons:

  1. The chemically manufactured prebiotic FOS is a synthetic product. Since it is not naturally occurring, there may be effects that have not yet been determined.
  2. The prebiotics Inulin and FOS are inert in the mouth, stomach and small intestine because they are non-digestible carbohydrate (similarly, olestra is a non-digestible fat, adding no calories to the diet). Inulin and FOS cause undesirable side effects in the gastrointestinal tract (olestra causes separate, unrelated side effects).
  3. Inulin and fructooligosaccharide alter the metabolic activity of the colon by fermenting selected species of bacteria. Abnormal functions may occur.
  4. The safety of prebiotic products could be an issue, as they rapidly ferment in the colon and stimulate selective bacteria strains and bacteria species. Intestinal problems such as altered bowel habits, flatulence, bloating and abdominal pain may result.
  5. The prebiotics inulin and FOS could easily influence the growth of yeast, Klebsiella, or possibly other pathogenic organisms. Combining prebiotics and probiotics may counteract any benefits the probiotic supplements may provide.
  6. You must know if the prebiotic supplements will nourish and stimulate the growth of the particular bacteria strains and bacteria species present in the product. Why should the manufacturers include FOS or inulin in their product if they cannot prove that the bacteria strains included in their product will use it?
  7. Bacteria are not simple organisms. They are very adept in using whatever sources of nourishment benefit their dominance over other resident microflora. Using direct substrates such as inulin or FOS changes the normal balance of resident bacteria species, and may lead to unhealthy distortions in the bacterial composition of the host microflora.


International GMP certified and audited by Australia's TGA (Therapeutic Goods Administration)

Signatory to the PIC/S (Pharmaceutical Inspection Convention / Scheme, Geneva Switzerland). Forty countries are signatories to this international convention, including America's Food and Drug Administration. This international certification process mirrors pharmaceutical guidelines, and is very stringent to assure quality is built into products every step of the way. We know of no other custom probiotic company that has this certification.

*Other commercial names may be used. **Natren has no data to show this is a natural process. Unsolicited information provided to Natren by manufacturer. Whether inulin is produced by a natural or artificial process is unknown to Natren. Issued June 16, 2003; supercedes previous Natren communications on FOS.

1. Niness, K.R. Inulin and Oligofructose: What are they? J Nutr 1999; 129:1402S-1406S.

2. Gibson, G.R., Roberfroid, M.B. Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics. J Nutr 1995; 125(6):1401-12.

3. Apajalahati, J.H.A. et al. Culture-independent microbial community analysis reveals that inulin in the diet primarily affects previously unknown bacteria in the mouse cecum. Appl Environ Microbiol 2002; 68(10):4986-95.

4. Cummings, J.H., Macfarlane, G.T., Englyst, H.N. Prebiotic digestion and fermentation. Am J Clin Nutr 2001; 73(Suppl):415S-20S.

5. Pajari, A.M., Oikarinen, S., Grasten, S., Mutanen, M. Diets enriched with cereal brans or inulin modulate protein kinase C activity and isozyme expression in rat colonic mucosa. Br J Nutr 2000; 84(5):635-43.

6. Mutanen, M., Pajari, A.M., Oikarinen, S.I. Beef induces and rye bran prevents the formation of intestinal polyps in Apc(Min) mice: relation to beta-catenin and PKC isozymes. Carcinogenesis 2000; 21(6):1167-73.

7. Oikarinen, S.I., Pajari, A.M., Mutanen, M. Chemopreventative activity of crude hydroxsymatairesinol (HMR) extract in Apc(Min) mice. Cancer Lett 2000; 161(2):253-8.

8. Salminen, S., Roberfroid, M., Ramos, P., Fonden, R. Prebiotic Substrates and Lactic Acid Bacteria. In: Lactic Acid Bacteria. Microbiological and Functional Aspects. Seppo Salminen, Atte von Wright (Eds.) 2nd Edition. New York: Marcel Dekker Inc., 1998. p. 343-58.

9. European Commission. Scientific Advisory Commission on Nutrition SACN/02/01, Fructo-oligosaccharides (FOS) and Galacto-oligosaccharides (GOS) in Infant Formulae. 27/03/02. http://www.doh.gov.uk/sacn/sacn0201.pdf

10. Hidaka, H., Eida, T., Takizawa, T., Tokunaga, T., Tashiro, Y. Effects of fructooligosaccharides on intestinal flora and human health. Bifidobacteria Microflora. 1986; 5(1):37-50.

11. Tani, Y., Sato, H., Tanaka, N., Hukuda, S. Antibodies against bacterial lipopolysaccharides in Japanese patients with ankylosing spondylitis. British Journal of Rheumatology. 1997; 36:491-3.

12. Ebringer, A. et al. Molecular mimicry: the geographical distribution of immune responses to Klebsiella in ankylosing spondylitis and its relevance to therapy. Clin Rheumatol. 1996; 15 suppl 1:57-61.

13. Maki-Ikola, O., Lehtinen, K., Nissila, M., Granfors, K. IgM, IgA and IgG class serum antibodies against Klebsiella pneumoniae and Escherichia coli lipopolysaccharides in patients with ankylosing spondylitis. Br J Rheumatol. 1994; 33(11):1025-9.

14. Shnayerson, M., Plotkin, M. The Killers Within. Boston: Little, Brown and Company, 2002. p.210.

15. Oda, Y., Ouchi, K. Construction of a sucrose-fermenting bakers� yeast incapable of hydrolyzing fructooligosaccharides. Enzyme Microb Technol. 1991; 13(6):495-498.

16. Poncet, S., Jacob, F.H., Berton, M-C., Couble, A. [Alcoholic fermentation of inulin by various strains of yeasts]. Ann Inst Pasteur/Microbiol. 1985;136B(1):99-109.

17. Kaplan, H., Hutkins, R.W. Fermentation of fructooligosaccharides by lactic acid bacteria and Bifidobacteria. Appl Environ Microbiol. 2000;66(6):2682-2684. PREBIOTICS *


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