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.12 People with flourishing intestinal colonies of
beneficial bacteria are better equipped to fight the growth of disease-causing
bacteria.34 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.56 Probiotic bacteria also
produce substances called bacteriocins, which act as natural antibiotics to kill undesirable
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):
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
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.89 No such adverse reactions have been
reported with other probiotic supplements or in people with normal immune systems.
Are there any drug
Certain medicines may interact with probiotics. Refer to drug interactions for a list of those medicines.
References (To view, roll mouse over the "References" heading; to hide, click on the heading)
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
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
4. Veldman A. Probiotics. Tijdschrift voor Diergeneeskunde
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
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.
The information presented in Aisle7 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 pharmacist
for any health problem and before using any supplements or before making any changes in