Also indexed as: Acidophilus, Bifidobacterium bifidum, Bifidobacterium longum, Intestinal Flora, Lactobacillus acidophilus, Lactobacillus casei, Saccharomyces boulardii
Probiotic bacteria favorably 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 yogurt—have been used as a folk remedy for hundreds, if not thousands, of years. Yogurt is the traditional source of beneficial bacteria. However, different brands of yogurt can vary greatly in their bacteria strain and potency. Some (particularly frozen) yogurts 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):
| Science Rating | Health Concerns |
|---|---|
 | Diarrhea Tooth decay (Lactobacillus GG) Vaginitis (Lactobacillus acidophilus [vaginal application]) Yeast infection |
 | Canker sores Colic (Bifidobacterium lactis and Streptococcus thermophilus) Crohn’s disease(Saccharomyces boulardii) Eczema Food allergies HIV support (Saccharomyces boulardii) Immune function Infection Pancreatitis (acute) (Lactobacillus plantarum) Ulcerative colitis Vaginitis (Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 [orally]) |
 | Chronic candidiasis Stress |
| Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit. | |
Who is likely to be deficient?
People using antibiotics, eating a poor diet, or suffering from diarrhea 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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2006-09-07
