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Other common
name(s): lactic acid bacteria
Scientific/medical
name(s): Lactobacillus
acidophilus (L.
acidophilus)
Description
Acidophilus is a type of germ or bacterium commonly found in
the normal digestive tract of mammals, mainly in the small intestine.
It is also found in many dairy products, especially yogurt. Acidophilus
and some related bacteria are considered to be "probiotic" because they
may help the body maintain or restore its normal balance of helpful
bacteria.
Overview
Acidophilus has been promoted for a wide variety of
conditions, including cancer. There have been no studies with humans on
the role of Lactobacillus
acidophilus in preventing or treating human cancers.
Animal studies looking at the role of L. acidophilus in
reducing the risk of cancer have shown varying results. Further
research is needed.
How is it promoted for use?
Acidophilus is often promoted as a supplement to help
"maintain a healthy bowel." It has also been suggested to prevent or
treat diarrhea and vaginal infections, to lower cholesterol, to help
with lactose digestion in lactose-sensitive people, and to help prevent
the growth of disease-causing bacteria and yeast.
Some supporters claim acidophilus may lower the risk of
cancer, especially colon cancer. It is supposed to do this by
neutralizing cancer-causing agents (carcinogens) in the diet and by
directly killing tumor cells. Some also claim that acidophilus works
against cancer by boosting the immune system by making B vitamins and
vitamin K, and that it reduces levels of cholesterol, which proponents
say tumor cells need in order to grow.
What does it involve?
When taking acidophilus, the dosage usually refers to the
number of live bacteria. Most sources suggest one to 10 billion
bacteria as a recommended dose. This amount is available in tablets,
capsules, and powder form. Average dosage suggestions vary from one to
3 times per day. However, some scientists warn that the concentration
of the bacteria in the supplements varies widely from one manufacturer
to another. Yogurt with "live cultures" and milk with L. acidophilus
added to it are other sources.
What is the history behind it?
Interest in the health benefits of acidophilus began in the
late 1800s when it was proposed that the long life span of the Balkan
people was due to their ingestion of fermented milk products. It was
later found that these milk products were rich in L. acidophilus.
Since then, the exact role of L.
acidophilus in the digestive tract and in human health has
been a controversial subjects, with few clear results.
What is the evidence?
Laboratory and animal studies on the ability of L. acidophilus to
prevent cancer have had mixed results, and there have been no large
studies reported in humans. L.
acidophilus has been studied in the laboratory for
possible antitumor properties. In some studies, milk that was fermented
by L. acidophilus
was able to slow or prevent the growth of breast and colon cancer cells
grown in the laboratory.
In other studies, animals that were given L. acidophilus were
found to be less prone to DNA damage in the colon after being given
known carcinogens, suggesting acidophilus might have an effect on colon
cancer. However, animal studies have shown that diets that include L. acidophilus do
not seem to affect the formation of breast or skin cancers. In either
case, randomized studies in people have not been done. Further studies
are needed to determine whether the results apply to humans.
Researchers have also studied the effects of L. acidophilus and
other probiotics on certain reproductive hormones known in high levels
to increase risk of breast cancer. In studies of both pre- and
post-menopausal women, L.
acidophilus had no effect.
A Japanese study looked at the effect of a related bacterium (Lactobacillus casei)
on the risk of colon tumors in about four hundred men and women who had
previous tumors removed. The risk of new tumor development was not
significantly lower in those who took L. casei, although
the tumors that did develop contained cells that were less abnormal.
A review of research on the effects of acidophilus and other
closely related bacteria found that they lowered cholesterol in some,
but not all, studies. It also found that a related bacterium (Lactobacillus GG)
may shorten the duration of diarrhea due to viral or bacterial
infections, but other health effects of these types of bacteria are not
clear.
A few recent studies suggest that acidophilus or related
Lactobacillus species may reduce the severity of diarrhea occurring
with chemotherapy for colorectal cancer or with radiation therapy for
colorectal or cervical cancer. On study suggest that adding
Lactobacillus to chemotherapy instilled into the bladder might help
prevent recurrence of bladder cancer after surgery.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike drugs (which must be
tested before being allowed to be sold), the companies that make
supplements are not required to prove to the Food and Drug
Administration that their supplements are safe or effective, as long as
they don't claim the supplements can prevent, treat, or cure any
specific disease.
Some such products may not
contain the amount of the herb or substance that is written on the
label, and some may include other substances (contaminants). Actual
amounts per dose may vary between brands or even between different
batches of the same brand.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
There appear to be few short-term problems with taking
acidophilus. Some people have reported excess bloating or gas for the
first few days while taking the supplement. In rare cases, acidophilus
may cause serious infections that are hard to treat with antibiotics.
People with weakened immune systems, such as those who are taking
steroids or undergoing chemotherapy, who have received organ
transplants, or who have AIDS, should use acidophilus with caution.
The lack of standardization makes it hard to be sure of the
quality of acidophilus products. Because acidophilus must contain live
cultures in order to be effective, proper packaging and storage is
essential. Many products may contain other bacteria or may not contain
enough of the active organisms, especially if the product has been
sitting on a shelf for a while.
Relying on this type of treatment alone and avoiding or
delaying conventional medical care for cancer may have serious health
consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
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G. Use of HT-29, a cultured human colon cancer cell line, to study the
effect of fermented milks on colon cancer cell growth and
differentiation. Carcinogenesis.
1995;16:245-252.
Biffi A, Coradini D, Larsen R, Riva L, Di Fronzo G.
Antiproliferative effect of fermented milk on the growth of a human
breast cancer cell line. Nutr
Cancer. 1997;28:93-99.
Bolognani F, Rumney CJ, Pool-Zobel BL, Rowland IR. Effect of
lactobacilli, bifidobacteria and inulin on the formation of aberrant
crypt foci in rats. Eur
J Nutr. 2001;40:293-300.
Bonorden MJ, Greany KA, Wangen KE. et al. Consumption of
Lactobacillus acidophilus and Bifidobacterium longum do not alter
urinary equol excretion and plasma reproductive hormones in
premenopausal women. European
Journal of Clinical Nutrition. 2004;58:1635-1642.
Delia P, Sansotta G, Donato V, FrosinaP, Messina G, De Renzis
C, Famularo G. Use of probiotics for prevention of radiation-induced
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Gastroenterol. 2007;13:912-915.
de Roos NM, Katan MB. Effects of probiotic bacteria on
diarrhea, lipid metabolism, and carcinogenesis: a review of papers
published between 1988 and 1998. Am
J Clin Nutr. 2000;71:405-411.
Ishikawa H, Akedo I, Otani T, et al.Randomized trial of
dietary fiber and Lactobacillus casei administration for prevention of
colorectal tumors. Int J
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Hove H, Norgaard H, Mortensen PB. Lactic acid bacteria and the
human gastrointestinal tract. Eur
J Clin Nut. 1999;53:339-350.
M. D. Anderson Cancer Center. Lactobacillus acidophilus.
Accessed at:
http://www.mdanderson.org/departments/cimer/display.cfm?id=28A0EE0D-11E2-4060-B5CEE2CE90A7295B&method=displayFull&pn=6EB86A59-EBD9-11D4-810100508B603A14
on June 10, 2008.
Naito S, Koga H, Yamaguchi A, Fujimoto N, Hasui Y, Kuramoto H,
Kinukawa N, Kyushu University Urological Oncology Group. Prevention of
recurrence with epirubicin and lactobacillus casei after transurethral
resection of bladder cancer.
J Urol. 2008;179:485-490.
Nettleton JA, Greany KA, Thomas W, Wangen KE, Adlercreutz H,
Kurzer MS. Short-term soy and probiotic supplementation does not
markedly affect concentrations of reproductive hormones in
postmenopausal women with and without histories of breast cancer. Journal of Alternative &
Complementary Medicine. 2005;11:1067-1074.
Osterlund P, Ruotsalainen T, Korpela R, Saxelin M, Ollus A,
Valta P, Kouri M, Elomaa I, Joensuu H. Lactobacillus supplementation
for diarrhoea related to chemotherapy of colorectal cancer: a
randomised study. Br J
Cancer. 2007;97:1028-1034.
Pool-Zobel BL, Neudecker C, Domizlaff I, et al.
Lactobacillus-and bifidobacterium-mediated antigenotoxicity in the
colon of rats. Nutr
Cancer. 1996;26:365-380.
Rao CV, Sanders ME, Indranie C, Simi B, Reddy BS. Prevention
of colonic preneoplastic lesions by the probiotic Lactobacillus
acidophilus NCFMTM in F344 rats. Int
J Oncol. 1999;14:939-944.
Rice LJ, Chai YJ, Conti CJ, Willis RA, Locniskar MF. The
effect of dietary fermented milk products and lactic acid bacteria on
the initiation and promotion stages of mammary carcinogenesis. Nutr Cancer.
1995;24:99-109.
Note:
This
information may not cover all possible claims, uses, actions,
precautions, side effects or interactions. It is not intended as
medical advice, and should not be relied upon as a substitute for
consultation with your doctor, who is familiar with your medical
situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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