Also indexed as: Acidophilus, Bifidobacterium bifidum, Bifidobacterium longum, Intestinal Flora, Lactobacillus acidophilus, Lactobacillus casei, Saccharomyces boulardii
Probiotic bacteria favourably alter the intestinal microflora balance, inhibit
the growth of harmful bacteria, promote good digestion, boost immune
function,
and increase resistance to infection.1 2
People with flourishing intestinal colonies of beneficial bacteria are better
equipped to fight the growth of disease-causing bacteria.3 4 Lactobacilli and bifidobacteria maintain a healthy balance
of intestinal flora by producing organic compounds—such as lactic acid,
hydrogen peroxide, and acetic acid—that increase the acidity of the intestine
and inhibit the reproduction of many harmful bacteria.5 6 Probiotic bacteria also produce substances called bacteriocins,
which act as natural antibiotics to kill undesirable
microorganisms.7
Where are they found?
Beneficial bacteria present in fermented dairy foods—namely live culture yoghurt—have been used as a folk remedy for hundreds, if not thousands, of years. Yoghurt is the traditional source of beneficial bacteria. However, different brands of yoghurt can vary greatly in their bacteria strain and potency. Some (particularly frozen) yoghurts do not contain any live bacteria. Supplements in powder, liquid extract, capsule, or tablet form containing beneficial bacteria are other sources of probiotics.
Probiotics have been used in connection with the following conditions (refer to the individual health concern for complete information):
Who is likely to be deficient?
People using antibiotics, eating a poor diet, or suffering from diarrhoea are more likely to have depleted colonies of friendly bacteria.
How much is usually taken?
The amount of probiotics necessary to replenish the intestine varies according to the extent of microbial depletion and the presence of harmful bacteria. One to two billion colony forming units (CFUs) per day of acidophilus is considered to be the minimum amount for the healthy maintenance of intestinal microflora. Some Saccharomyces boulardii research has used 500 mg taken four times per day.
Are there any side effects or interactions?
There are at least nine case reports of severe, invasive (internal) fungal infections developing in people treated with the yeast organism Saccharomyces boulardii. All of these people were debilitated or had impaired immune function prior to receiving Saccharomyces boulardii.8 9 No such adverse reactions have been reported with other probiotic supplements or in people with normal immune systems.
Acidophilus and bifidobacteria may manufacture B vitamins, including niacin, folic acid, biotin, and vitamin B6.
Are there any drug interactions?
Certain medicines may interact with probiotics. Refer to drug interactions for a list of those medicines.
References
1. Smirnov VV, Reznik SR, V’iunitskaia
VA, et al. The current concepts of the mechanisms of the
therapeutic-prophylactic action of probiotics from bacteria in the genus
bacillus. Mikrobiolohichnyi Zhurnal 1993;55:92–112.
2. Mel’nikova
VM, Gracheva NM, Belikov GP, et al. The chemoprophylaxis and chemotherapy of
opportunistic infections. Antibiotiki i Khimioterapiia 1993;38:44–8.
3. De Simone C,
Vesely R, Bianchi SB, et al. The role of probiotics in modulation of the immune
system in man and in animals. Int J Immunother 1993;9:23–8.
4. Veldman A. Probiotics. Tijdschrift voor Diergeneeskunde
1992;117:345–8.
5. Kawase K. Effects of
nutrients on the intestinal microflora of infants. Jpn J Dairy Food Sci
1982;31:A241–3.
6. Rasic JL. The role of dairy foods containing bifido
and acidophilus bacteria in nutrition and health. N Eur Dairy J
1983;4:80–8.
7. Barefoot SF, Klaenhammer TR. Detection and activity of
Lactacin B, a Bacteriocin produced by Lactobacillus acidophilus. Appl
Environ Microbiol 1983;45:1808–15.
8. Bassetti S, Frei R, Zimmerli W. Fungemia with Saccharomyces cerevisiae after treatment with Saccharomyces boulardii. Am J Med 1998;105:71–2.
9. Perapoch J, Planes AM, Querol A, et al. Fungemia with Saccharomyces cerevisiae in two newborns, only one of whom had been treated with Ultra-Levura. Eur J Clin Microbiol Infect Dis 2000;19:468–70.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.
2007-09-01