Supplement research


Prebiotics and Probiotics

Introduction

The gastrointestinal tract (gut) contains large numbers of bacteria. Organisms are present in the oral cavity, the stomach, the small intestine, the large intestine and colon. The balance of these bacteria is very important for human health.

There are over 400 different types of bacteria in the human colon. Some strains are pathogenic in that they produce toxins and carcinogens, whereas others are considered to induce health promoting functions e.g. bifidobacteria and lactobacillus. It is thought that nourishing these "good" bacteria or promoting their growth allows them to out compete potential detrimental organisms, thereby potentially contributing to the health of the host (1).

Two potential ways to influence the balance of bacteria in the colon and thus promote health are known as probiotics and prebiotics.

Probiotics

Probiotics are live microorganisms present in foods or supplements which benefit health by improving intestinal microbial balance (2). Probiotics can contribute to intestinal microbial balance and support intestinal health by inhibiting the overgrowth of toxic bacteria. By competing for attachment sites and nutrients, these beneficial bacteria may inhibit the proliferation of non-beneficial or toxic organisms. The most commonly used probiotic bacteria are Lactobacilli and Bifidobacteria.

Prebiotics

Whereas probiotics involves adding microorganisms to ingested food, prebiotics is where the food actually contains a substrate which influences the growth of the beneficial bacteria already present in the colon. Therefore prebiotics are food-induced increases in the numbers and/or activity of bacteria in the human intestine. A common definition of a prebiotic is: a non-digestible food ingredient that may beneficially affect the host by selectively stimulating the growth and /or activity of one or a limited number of bacteria in the colon that may improve the host health. One of the potential benefits of prebiotics over probiotics is that the former overcomes the problem of survival in the upper gastrointestinal tract. Prebiotics are not digested in the small intestine of humans and therefore enter the colon intact. Some common prebiotics are the non-digestible carbohydrates inulin and oligofructose, as well as other oligosaccharides. These substances escape digestion in the gastrointestinal tract and enter the colon where bacteria can use them as a substrate.

Combination of Prebiotics and Probiotics

Prebiotics are often used in combination with probiotics. Foods and supplements which combine both prebiotics and probiotics are known as synbiotic foods. This combination may be advantageous because in addition to the action of prebiotics which promote the growth of existing strains of beneficial bacteria in the colon, prebiotics may also improve the implantation, survival and growth of newly added probiotic strains (3).

Beneficial Bacteria

Of the several hundred bacteria which colonise the large intestine, Bifidobacteria are generally considered to be health promoting and beneficial. Predominance of bifidobacteria is recognised as being essential for the prevention of diseases and maintenance of good health.

Lactobacillus strains of bacteria are also important for health. Lactobacillus as well as Bifidobacteria produce organic acids that reduce the pH (that is they increase the acidity) of the intestine. This retards the growth of pathogenic (disease causing) acid-sensitive bacteria (4).

Lactobacillus acidophilus has been found to significantly lower the levels of faecal enzymes that are associated with colon carcinogenesis (4).

Lactobacillus casei has been shown to reduce the incidence and duration of episodes of diarrhoea in children. Other studies have shown that although Lactobacillus casei did not affect the incidence of winter infections (gastrointestinal and respiratory) it may reduce their duration by about 20% (5).

Potential Benefits of Probiotics

Probiotics are being increasingly studied for their ability to enhance host resistance to, and recovery from, infection.
In vitro (experiments in the laboratory i.e. not in the human body) studies have shown that Lactobacillus casei, Lactobacillus bifidum and Lactobacillus acidophilus have potential anticarcinogenic effects (4). These bacteria may elicit their anticarcinogenic effects by several mechanisms:

  • Bind, block or remove carcinogens
  • Inhibit bacteria which directly or indirectly convert procarcinogens to carcinogens by enzyme activity
  • Activate the host's immune system to act against tumours
  • Reduce the intestinal pH (i.e. increase acidity), thereby altering microbial activity, solubility of bile acids, mucus secretions
  • Alter colonic motility and transit time
    (6).

These potential beneficial effects continue to be researched.

Overall it has been proposed that the beneficial effects of probiotics may include:

  • alleviation of the symptoms of lactose intolerance
  • immune system enhancement
  • shorter duration of diarrhoea caused by rotavirus
  • decreased faecal mutagenicity
  • decreased faecal bacterial enzyme activity and prevention of the recurrence of superficial bladder cancer(7).

Potential benefits of Prebiotics

Some potential beneficial effects of prebiotics include:

  • Constipation relief due to faecal bulking and possible effects on intestinal motility (8)
  • Inhibition of diarrhoea, especially associated with intestinal infections (9)
  • Promising evidence for improvement of the bioavailability of minerals such as calcium (10-12)
  • Preliminary evidence for improvement of high blood triglyceride levels (associated with an increased risk of heart disease (13,14)
  • Preliminary evidence from animal studies suggest a possible role for reducing colon cancer (15-17)
  • Possible immune stimulation (18)

Of these potential benefits it seems that improved resistance to pathogens offers the most feasibility. One of the mechanisms suggested for this is the increase in metabolic end products excreted by microorganisms may decrease the pH (i.e. increase acidity), to levels below which pathogens are able to effectively compete. Also increasing the numbers of beneficial bacteria increases competition for attachment sites and nutrients. Also many Lactobacilli and Bifidobacterial species are able to excrete natural antibiotics which have a broad spectrum of activity (9).

Short chain oligofructose escape digestion in the upper small intestine and reach the colon where they are fermented mostly to lactate and short chain fatty acids (butyrate, propionate, acetate). It is likely that their most important ability is to specifically stimulate Bifidobacterial growth which induces the production of butyrate. This has been shown to play a role in the prevention and progression of experimental colorectal carcinogenesis.

Benefits of added prebiotics such as inulin and oligofructose on the stimulation of bifidobacteria have been shown at doses of 4-5g/day (3,19,20). Other potential benefits such as enhanced calcium absorption have been shown at doses of 15-40g per day (21).

References

1.  Jenkins D.J.A., Kendall C.W.C. and Vuksan V. Inulin, oligofructose and intestinal function. J Nutr. 129:1431S-1433S, 1999.
2.  Fuller R. Probiotics: The Scientific Basis. London: Chapman & Hall, 1992
3.  Gibson G. and Robertfroid M. Dietary modulation of the human colonic microflora: introducing the concept of prebiotics. J Nutr. 125:1401-1412, 1995.
4.  Bronzetti G. Antimutagens in food. Trends in Food Science and Technology. 5:390-395, 1994.
5.  Turchet P., Laurenzano M., Auboiron S. and Antoine J.M. Effect of fermented milk containing the probioitic Lactobacillus casei DN-114 001 on winter infections in free-living elderly subjects: a randomised controlled pilot study. J Nutr Health Aging. 7:75-77, 2003.
6.  McIntosh G.H. Probiotics and colon cancer prevention. Asia Pacific J Clin Nutr. 1009:5, 1996.
7.  Salaminen S., Bouley C., Boutron-Rualt M.C., Cummings J.H., Franck A., Gibson G., Isolauri E., Moreau M.C., Robertfroid M. and Rowland I. Functional food science and gastrointestinal physiology and function. Br J Nutr. 80, 1998.
8.  Kleessen B., Sykura B., Zunft H.J. and Blaut M. Effects of inulin and lactose on faecal microflora, microbial activity, and bowel habit in elderly constipated persons. Am J Clin Nutr. 65:1397-1402, 1997.
9.  Gibson G. and Wang X. Inhibitory effects of bifidobacteria on other colonic bacteria. J Appl Bactriol. 65:103-111, 1994.
10.  Coudray C., Bellanger J., Castiglia-Delavaud C., R?sy C., Vermorel M. and Rayssignuier Y. Effect of soluble or partly soluble dietary fibres supplementation on absorption and balance of calcium. magnesium, iron and zinc in healthy young men. Eur J Clin Nutr. 51:375-380, 1997.
11.  Delzenne N., Aerssens J., Verplaetse H., Roccaro M. and Robertfroid M. Effect of fermentable fructo-oligosaccharides on mineral, nitrogen and energy digestive balance in the rat. Life Sci. 57:1579-1587, 1995.
12.  Ohta A., Ohtsuki M., Hosono A., Adachi T., Hara H. and Sakata T. Dietary fructooligosaccharides prevent osteopenia after gastrectomy in rats. J Nutr. 128:106-110, 1998.
13.  Fiordaliso M., Kok N., Desager J.P., Goethals F., Deboyser D., Robertfroid M. and Delzenne N. Dietary oligofructose lowers triglycerides, phospholipids and cholesterol in serum and very low density lipoproteins of rats. Lipids. 30:163-167, 1995.
14.  Kok N., Robertfroid M. and Delzenne N. Dietary oligofructose modifies the impact of fructose on hepatic triacylglycerol metabolism. Metabolism. 45:1547-1550, 1996.
15.  Koo M. and Rao A.V. Long term effect of Bifidobacteria and neosugar on precursor lesions of colonic cancer in CF1 mice. Nutr Cancer. 16:249-257, 1991.
16.  Pierre F., P P., Champ M., Bornet F., Meflah K. and Menanteau J. Short-chain fructo-oligosaccharides reduced the occurrence of colon tumors and develop gut-associated lymphoid tissue in Min mice. Cancer Res. 57:225-228, 1997.
17.  Taper H.S., Delzenne N. and Robertfroid M. Growth inhibition of transplantable mouse tumors by non-digestible carbohydrates. Int J Cancer. 71:1109-1112, 1997.
18.  Jenkins D.J.A., Kendall C.W.C., Ransom T.P.P., Popovich D.G., Tariq N., Wolever T.M.S., Rao A.V., Thompson L.U. and Cunnane S.C. Dietary fibre and cholesterol lowering: future directions. In: Dietary fibre in health and disease. D. Kritchevsky and C. Bonfield (Eds.) New York: Plenum Publishing, 1997.
19.  Reading S., Aramendi S., Gibson G. and McCarteny A. An in vitro investigation of the minimum fructo-oligosaccharide dose affording a preboitic effect. Profibre. Lisbon, 1998.
20.  Williams C., Witherly S. and Buddington R. Influence of dietary neosugar on selected bacterial groups of the human faecal mircobiotia. Microb Eco Health Dis. 7:91-97, 1993.
21.  Rao A.V. Dose-response effects of inulin and oligofructose on intestinal bifidogenesis effects. J Nutr. 129:1442S-1445S, 1999.



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Supplement research


Prebiotics and Probiotics

Introduction

The gastrointestinal tract (gut) contains large numbers of bacteria. Organisms are present in the oral cavity, the stomach, the small intestine, the large intestine and colon. The balance of these bacteria is very important for human health.

There are over 400 different types of bacteria in the human colon. Some strains are pathogenic in that they produce toxins and carcinogens, whereas others are considered to induce health promoting functions e.g. bifidobacteria and lactobacillus. It is thought that nourishing these "good" bacteria or promoting their growth allows them to out compete potential detrimental organisms, thereby potentially contributing to the health of the host (1).

Two potential ways to influence the balance of bacteria in the colon and thus promote health are known as probiotics and prebiotics.

Probiotics

Probiotics are live microorganisms present in foods or supplements which benefit health by improving intestinal microbial balance (2). Probiotics can contribute to intestinal microbial balance and support intestinal health by inhibiting the overgrowth of toxic bacteria. By competing for attachment sites and nutrients, these beneficial bacteria may inhibit the proliferation of non-beneficial or toxic organisms. The most commonly used probiotic bacteria are Lactobacilli and Bifidobacteria.

Prebiotics

Whereas probiotics involves adding microorganisms to ingested food, prebiotics is where the food actually contains a substrate which influences the growth of the beneficial bacteria already present in the colon. Therefore prebiotics are food-induced increases in the numbers and/or activity of bacteria in the human intestine. A common definition of a prebiotic is: a non-digestible food ingredient that may beneficially affect the host by selectively stimulating the growth and /or activity of one or a limited number of bacteria in the colon that may improve the host health. One of the potential benefits of prebiotics over probiotics is that the former overcomes the problem of survival in the upper gastrointestinal tract. Prebiotics are not digested in the small intestine of humans and therefore enter the colon intact. Some common prebiotics are the non-digestible carbohydrates inulin and oligofructose, as well as other oligosaccharides. These substances escape digestion in the gastrointestinal tract and enter the colon where bacteria can use them as a substrate.

Combination of Prebiotics and Probiotics

Prebiotics are often used in combination with probiotics. Foods and supplements which combine both prebiotics and probiotics are known as synbiotic foods. This combination may be advantageous because in addition to the action of prebiotics which promote the growth of existing strains of beneficial bacteria in the colon, prebiotics may also improve the implantation, survival and growth of newly added probiotic strains (3).

Beneficial Bacteria

Of the several hundred bacteria which colonise the large intestine, Bifidobacteria are generally considered to be health promoting and beneficial. Predominance of bifidobacteria is recognised as being essential for the prevention of diseases and maintenance of good health.

Lactobacillus strains of bacteria are also important for health. Lactobacillus as well as Bifidobacteria produce organic acids that reduce the pH (that is they increase the acidity) of the intestine. This retards the growth of pathogenic (disease causing) acid-sensitive bacteria (4).

Lactobacillus acidophilus has been found to significantly lower the levels of faecal enzymes that are associated with colon carcinogenesis (4).

Lactobacillus casei has been shown to reduce the incidence and duration of episodes of diarrhoea in children. Other studies have shown that although Lactobacillus casei did not affect the incidence of winter infections (gastrointestinal and respiratory) it may reduce their duration by about 20% (5).

Potential Benefits of Probiotics

Probiotics are being increasingly studied for their ability to enhance host resistance to, and recovery from, infection.
In vitro (experiments in the laboratory i.e. not in the human body) studies have shown that Lactobacillus casei, Lactobacillus bifidum and Lactobacillus acidophilus have potential anticarcinogenic effects (4). These bacteria may elicit their anticarcinogenic effects by several mechanisms:

  • Bind, block or remove carcinogens
  • Inhibit bacteria which directly or indirectly convert procarcinogens to carcinogens by enzyme activity
  • Activate the host's immune system to act against tumours
  • Reduce the intestinal pH (i.e. increase acidity), thereby altering microbial activity, solubility of bile acids, mucus secretions
  • Alter colonic motility and transit time
    (6).

These potential beneficial effects continue to be researched.

Overall it has been proposed that the beneficial effects of probiotics may include:

  • alleviation of the symptoms of lactose intolerance
  • immune system enhancement
  • shorter duration of diarrhoea caused by rotavirus
  • decreased faecal mutagenicity
  • decreased faecal bacterial enzyme activity and prevention of the recurrence of superficial bladder cancer(7).

Potential benefits of Prebiotics

Some potential beneficial effects of prebiotics include:

  • Constipation relief due to faecal bulking and possible effects on intestinal motility (8)
  • Inhibition of diarrhoea, especially associated with intestinal infections (9)
  • Promising evidence for improvement of the bioavailability of minerals such as calcium (10-12)
  • Preliminary evidence for improvement of high blood triglyceride levels (associated with an increased risk of heart disease (13,14)
  • Preliminary evidence from animal studies suggest a possible role for reducing colon cancer (15-17)
  • Possible immune stimulation (18)

Of these potential benefits it seems that improved resistance to pathogens offers the most feasibility. One of the mechanisms suggested for this is the increase in metabolic end products excreted by microorganisms may decrease the pH (i.e. increase acidity), to levels below which pathogens are able to effectively compete. Also increasing the numbers of beneficial bacteria increases competition for attachment sites and nutrients. Also many Lactobacilli and Bifidobacterial species are able to excrete natural antibiotics which have a broad spectrum of activity (9).

Short chain oligofructose escape digestion in the upper small intestine and reach the colon where they are fermented mostly to lactate and short chain fatty acids (butyrate, propionate, acetate). It is likely that their most important ability is to specifically stimulate Bifidobacterial growth which induces the production of butyrate. This has been shown to play a role in the prevention and progression of experimental colorectal carcinogenesis.

Benefits of added prebiotics such as inulin and oligofructose on the stimulation of bifidobacteria have been shown at doses of 4-5g/day (3,19,20). Other potential benefits such as enhanced calcium absorption have been shown at doses of 15-40g per day (21).

References

1.  Jenkins D.J.A., Kendall C.W.C. and Vuksan V. Inulin, oligofructose and intestinal function. J Nutr. 129:1431S-1433S, 1999.
2.  Fuller R. Probiotics: The Scientific Basis. London: Chapman & Hall, 1992
3.  Gibson G. and Robertfroid M. Dietary modulation of the human colonic microflora: introducing the concept of prebiotics. J Nutr. 125:1401-1412, 1995.
4.  Bronzetti G. Antimutagens in food. Trends in Food Science and Technology. 5:390-395, 1994.
5.  Turchet P., Laurenzano M., Auboiron S. and Antoine J.M. Effect of fermented milk containing the probioitic Lactobacillus casei DN-114 001 on winter infections in free-living elderly subjects: a randomised controlled pilot study. J Nutr Health Aging. 7:75-77, 2003.
6.  McIntosh G.H. Probiotics and colon cancer prevention. Asia Pacific J Clin Nutr. 1009:5, 1996.
7.  Salaminen S., Bouley C., Boutron-Rualt M.C., Cummings J.H., Franck A., Gibson G., Isolauri E., Moreau M.C., Robertfroid M. and Rowland I. Functional food science and gastrointestinal physiology and function. Br J Nutr. 80, 1998.
8.  Kleessen B., Sykura B., Zunft H.J. and Blaut M. Effects of inulin and lactose on faecal microflora, microbial activity, and bowel habit in elderly constipated persons. Am J Clin Nutr. 65:1397-1402, 1997.
9.  Gibson G. and Wang X. Inhibitory effects of bifidobacteria on other colonic bacteria. J Appl Bactriol. 65:103-111, 1994.
10.  Coudray C., Bellanger J., Castiglia-Delavaud C., R?sy C., Vermorel M. and Rayssignuier Y. Effect of soluble or partly soluble dietary fibres supplementation on absorption and balance of calcium. magnesium, iron and zinc in healthy young men. Eur J Clin Nutr. 51:375-380, 1997.
11.  Delzenne N., Aerssens J., Verplaetse H., Roccaro M. and Robertfroid M. Effect of fermentable fructo-oligosaccharides on mineral, nitrogen and energy digestive balance in the rat. Life Sci. 57:1579-1587, 1995.
12.  Ohta A., Ohtsuki M., Hosono A., Adachi T., Hara H. and Sakata T. Dietary fructooligosaccharides prevent osteopenia after gastrectomy in rats. J Nutr. 128:106-110, 1998.
13.  Fiordaliso M., Kok N., Desager J.P., Goethals F., Deboyser D., Robertfroid M. and Delzenne N. Dietary oligofructose lowers triglycerides, phospholipids and cholesterol in serum and very low density lipoproteins of rats. Lipids. 30:163-167, 1995.
14.  Kok N., Robertfroid M. and Delzenne N. Dietary oligofructose modifies the impact of fructose on hepatic triacylglycerol metabolism. Metabolism. 45:1547-1550, 1996.
15.  Koo M. and Rao A.V. Long term effect of Bifidobacteria and neosugar on precursor lesions of colonic cancer in CF1 mice. Nutr Cancer. 16:249-257, 1991.
16.  Pierre F., P P., Champ M., Bornet F., Meflah K. and Menanteau J. Short-chain fructo-oligosaccharides reduced the occurrence of colon tumors and develop gut-associated lymphoid tissue in Min mice. Cancer Res. 57:225-228, 1997.
17.  Taper H.S., Delzenne N. and Robertfroid M. Growth inhibition of transplantable mouse tumors by non-digestible carbohydrates. Int J Cancer. 71:1109-1112, 1997.
18.  Jenkins D.J.A., Kendall C.W.C., Ransom T.P.P., Popovich D.G., Tariq N., Wolever T.M.S., Rao A.V., Thompson L.U. and Cunnane S.C. Dietary fibre and cholesterol lowering: future directions. In: Dietary fibre in health and disease. D. Kritchevsky and C. Bonfield (Eds.) New York: Plenum Publishing, 1997.
19.  Reading S., Aramendi S., Gibson G. and McCarteny A. An in vitro investigation of the minimum fructo-oligosaccharide dose affording a preboitic effect. Profibre. Lisbon, 1998.
20.  Williams C., Witherly S. and Buddington R. Influence of dietary neosugar on selected bacterial groups of the human faecal mircobiotia. Microb Eco Health Dis. 7:91-97, 1993.
21.  Rao A.V. Dose-response effects of inulin and oligofructose on intestinal bifidogenesis effects. J Nutr. 129:1442S-1445S, 1999.