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Lactobacillus acidophilus

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Lactobacillus acidophilus
Lactobacillus acidophilus

BackgroundReturn to top

Lactobacilli are bacteria that normally live in the human small intestine and vagina.  Lactobacillus acidophilus  is generally considered to be beneficial because it produces vitamin K, lactase, and anti-microbial substances such as acidolin, acidolphilin, lactocidin, and bacteriocin. Multiple human trials report benefits of  Lactobacillus acidophilus  for bacterial vaginosis. Other medicinal uses of  Lactobacillus acidophilus  are not sufficiently studied to form clear conclusions.

The term "probiotic" is used to describe organisms that are used medicinally, including bacteria such as  Lactobacillus acidophilus  and yeast such as  Saccharomyces boulardii .

Although generally believed to be safe with few side effects,  Lactobacillus acidophilus  taken by mouth should be avoided in people with intestinal damage, a weakened immune system, or with overgrowth of intestinal bacteria.

SynonymsReturn to top

Acidophilus, Acidophilus Extra Strength®, acidophilus milk, Actilact, Actimel®, Bacid®, Cultura®, DDS-Acidophilus, Endolac®, Enpac®, Fermalac® (Canadian), Florajen®, fresh poi, Gynoflor®, Infloran®, Kala®, Kyo-Dophilus®, L-92, Lacteol Fort®, lactic acid bacteria mixture (Oxadrop), lactic acid-producing bacteria (LAB), Lactinex®, Lactobacillaceae (family), lactobacilli, lactobacillus,  Lactobacillus acidophilus  145,  Lactobacillus acidophilus  DDS-1,  Lactobacillus acidophilus  LA 02,  Lactobacillus acidophilus  La5,  Lactobacillus acidophilus  L-92,  Lactobacillus acidophilus  milk,  Lactobacillus acidophilus  NCFM,  Lactobacillus acidophilus  OLL2769,  Lactobacillus acidophilus  NCK56,  Lactobacillus acidophilus  strain 27L,  Lactobacillus acidophilus  strain LB (LaLB),  Lactobacillus acidophilus  yogurt,  Lactobacillus  LB, Lacto Bacillus, MoreDophilus®, Narine®, poi, Probiata®, Pro-Bionate®, probiotic, sour poi, Superdophilus®, yogurt.

EvidenceReturn to top

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidenceGrade*
Bacterial vaginosis

Multiple human studies report that  Lactobacillus acidophilus  vaginal suppositories are effective in the treatment of bacterial vaginosis. A small number of studies suggest that eating yogurt enriched with  Lactobacillus acidophilus  may be similarly beneficial. Additional research is necessary before a firm conclusion can be reached. Patients with persistent vaginal discomfort are advised to seek medical attention.
Allergic disorders (Japanese cedar pollen)

A small study was conducted to evaluate the effects of  Lactobacillus acidophilus  strain L-92 (L-92) on the symptoms of Japanese cedar pollen allergy. Further research is needed before a decision can be made.

There is limited research in this area with unclear results.
Atopic dermatitis

There is currently not enough evidence to suggest a benefit of  Lactobacillus acidophilus  for this condition.
Breast cancer

Early studies in humans have failed to show a consistent benefit of  Lactobacillus acidophilus  in breast cancer. Further studies are needed.
Colitis (collagenous colitis)

Early studies fail to show a benefit of  Lactobacillus acidophilus  in this condition. More high-quality studies are needed.
Diarrhea prevention

A small amount of human research suggests that  Lactobacillus acidophilus  may not be effective when used to prevent diarrhea in travelers or in people taking antibiotics, but results are mixed. Several studies report that the related species,  Lactobacillus  GG, may be helpful for the prevention of diarrhea in children and travelers. Additional study is needed in these areas before a firm conclusion can be drawn.
Diarrhea treatment (children)

A small amount of research in children, using different forms of acidophilus, reports no improvement in diarrhea. Future studies should use a viable  Lactobacillus acidophilus  culture to assess effects on diarrhea.  Lactobacillus  GG, a different species, is suggested by multiple human studies to be a safe and effective treatment for diarrhea in otherwise healthy infants and children.  Lactobacillus acidophilus  may aid in the management of chronic or persistent diarrhea, bacterial-overgrowth related diarrhea, and acute watery diarrhea in infants. Further research is needed to determine what dose may be safe and effective.
H. pylori infection

Early studies in humans suggest a potential benefit of  Lactobacillus acidophilus  in this condition. More large, high-quality studies are needed to understand this relationship.
Hepatic encephalopathy (confused thinking due to liver disorders)

There is limited study in this area with mixed results.
High cholesterol

There is conflicting information from several human studies regarding the effects of  Lactobacillus acidophilus- enriched dairy products on lowering blood levels of total cholesterol or low-density lipoprotein ("bad cholesterol").

Early studies fail to show consistent evidence of benefit of  Lactobacillus acidophilus  in immunomodulation. Additional studies are needed.
Intestinal blockage (partial adhesive small-bowel obstruction)

Early studies suggest potential benefit of adjunct therapy with  Lactobacillus acidophilus  in this condition. Additional high-quality studies are needed.
Intestinal inflammation (pouchitis)

Early studies in humans have failed to show a benefit of  Lactobacillus acidophilus  in this condition. More studies are needed.
Irritable bowel syndrome

Human studies report mixed results in the improvement of bowel symptoms after taking  Lactobacillus acidophilus  by mouth.
Lactose intolerance

There is conflicting information from several human studies as to whether using  Lactobacillus acidophilus  by mouth improves digestion of lactose. More research is needed in this area a before a conclusion can be drawn.
Leaky gut syndrome (gut barrier function)

Early human studies suggest potential benefit of  Lactobacillus acidophilus  in the improvement of gut barrier function. More high-quality studies are needed to understand this relationship.
Necrotizing enterocolitis prevention in infants

One human study using  Lactobacillus acidophilus  in combination with another bacterium ( Bifidobacterium infantis ) in infants reported fewer cases of necrotizing enterocolitis (severe inflammation of the gut), and no complications related to treatment. Additional research is necessary in this area before a conclusion can be drawn.
Premature birth prevention

Early studies suggest a potential benefit of  Lactobacillus acidophilus  for prevention of premature birth. More studies are needed to clarify this relationship.
Vaginal candidiasis (yeast infection)

 Lactobacillus acidophilus  taken by mouth or as a vaginal suppository has not been adequately assessed for the prevention or treatment of vaginal yeast infections. More research is needed in this area a before a strong conclusion can be drawn.

*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.

Grading rationale

Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Acne, AIDS, antimutagenic (antigenotoxic), cancer, canker sores, colon cancer (prevention), constipation, Crohn's disease, diaper rash, diverticulitis, E. coli infection in cancer patients, fever blisters, gastric ulcer (ASA-induced alteration prevention), heart disease, heartburn, hives, indigestion, infection, overgrowth of bacteria in the small bowel, preoperative prevention of infections or gut bacteria loss, stomach ulcer, thrush, ulcerative colitis, urinary tract infection.

DosingReturn to top

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)
Expert opinion suggests that a dose between 1 and 10 billion viable (live)  Lactobacillus acidophilus  bacteria taken daily in divided doses by mouth is sufficient for most people. Higher doses may cause mild abdominal discomfort, and smaller doses may not be able to establish a stable population in the gut. For vaginal bacterial infections, a dose that has been used is 8 ounces of yogurt containing  Lactobacillus acidophilus  in a concentration of 100 million colony-forming units (108 CFU) in each milliliter. Capsules containing 1.5 grams of  Lactobacillus acidophilus  were used in one study.

Doses that have been used for vaginal infections include 1 to 2 tablets (containing 10 million to 1 billion CFU in each tablet), inserted into the vagina once or twice daily. Capsules containing 1.5 grams of  Lactobacillus acidophilus  have been used to treat diarrhea as anal suppositories.

Children (younger than 18 years)
Some natural medicine textbooks and experts suggest that one-quarter teaspoon or one-quarter capsule of commercially available  Lactobacillus acidophilus  may be safe for use in children for the replacement of gut bacteria destroyed by antibiotics. Up to 12 billion lyophilized heat-killed  Lactobacillus acidophilus  has been given every 12 hours by mouth for up to five days. It is often recommended that  Lactobacillus acidophilus  supplements be taken two hours after antibiotic doses because antibiotics may kill  Lactobacillus acidophilus  if taken at the same time. Consult a qualified healthcare practitioner prior to using  Lactobacillus acidophilus  in children, and use cautiously in those under three years of age.

Liquid preparations have been used on the diaper area to treat yeast infections, although safety and effectiveness are not well studied. Consult a qualified healthcare practitioner prior to using  Lactobacillus acidophilus  in children, and use cautiously in those under three years of age.

SafetyReturn to top

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Lactose sensitive people may develop abdominal discomfort from dairy products containing  Lactobacillus acidophilus .

Side Effects and Warnings
Studies report few side effects from  Lactobacillus acidophilus  when used at recommended doses. The most common complaint is abdominal discomfort or gas, which usually resolves with continued use. Some experts recommend limiting the daily dose of living  Lactobacillus acidophilus  organisms to reduce the risk of abdominal discomfort. Some women have reported burning of the vagina after using  Lactobacillus acidophilus  vaginal tablets.

There are rare reports of infections of heart valves with  Lactobacillus acidophilus , and the risk may be greater in people with artificial heart valves. People with severely weakened immune systems (due to disease or drugs like cancer chemotherapy and organ transplant immunosuppressants) may develop serious infections or bacteria in the blood from taking  Lactobacillus acidophilus . Therefore,  Lactobacillus acidophilus  should be avoided in such individuals. People with intestinal damage or recent bowel surgery should avoid taking lactobacilli.

Pregnancy and Breastfeeding
There is not enough scientific study available to establish safety during pregnancy. Therefore, pregnant women should use  Lactobacillus acidophilus  cautiously and under medical supervision, if at all. A small number of pregnant women have taken part in studies investigating  Lactobacillus acidophilus  vaginal tablets and a culture of  Lactobacillus acidophilus  with no negative effects reported. Further research is necessary.

InteractionsReturn to top

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs
Some experts believe that  Lactobacillus acidophilus  taken by mouth should be used two to three hours after antibiotic doses, to prevent killing the  Lactobacillus acidophilus . It has also been suggested that lactobacilli are damaged by alcohol and should not be taken at the same time. Scientific research is limited in these areas.

In theory,  Lactobacillus acidophilus  taken by mouth might not survive the acidic environment of the stomach. Some experts have suggested that antacids should be taken 30 to 60 minutes before taking lactobacilli. However, this has not been well studied in humans.

In theory,  Lactobacillus acidophilus  may prolong the effects of some drugs, including birth control pills, the contraceptive vaginal ring, or benzodiazepines such as diazepam (Valium®). Based on laboratory experiments,  Lactobacillus acidophilus  may reduce the effectiveness of sulfasalazine (Azulfidine®), a drug used for inflammatory bowel disease.

Interactions with Herbs and Dietary Supplements
Fructo-oligosaccharides (FOS, also called "prebiotics") are non-digestible sugar chains that are nutrients for lactobacilli. Some experts believe that FOS, taken by mouth, may help the growth of lactobacilli. Natural food sources of FOS include banana, Jerusalem artichoke, onion, asparagus, and garlic.

 Lactobacillus casei ,  Saccharomyces boulardi , or other probiotics may add to the effects of  Lactobacillus acidophilus .

Methodology Return to top

This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration ( Ethan Basch, MD, MPhil, MSc (Memorial Sloan-Kettering Cancer Center); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Ron Dixon, MD (Massachusetts General Hospital); Jenna Hollenstein, MS, RD (Natural Standard Research Collaboration); Carolyn Williams Orlando, MA (American Botanical Council); David Sollars, MAc, HMC (Merrimack College); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Mamta Vora, PharmD (Northeastern University); Lisa Wendt, PharmD (Albany College of Pharmacy); Wendy Weissner, BA (Natural Standard Research Collaboration).

Methodology details

Selected references Return to top

  1. Arvola T, Laiho K, Torkkeli S, et al. Prophylactic Lactobacillus GG reduces antibiotic-associated diarrhea in children with respiratory infections: a randomized study. Pediatrics 1999;104(5):e64.
  2. Delia A, Morgante G, Rago G, et al. Effectiveness of oral administration of Lactobacillus paracasei subsp. Paracasei F19 in association with vaginal suppositories of Lactobacillus acidofilus in the treatment of vaginosis and in the prevention of recurrent vaginitis. Minerva Ginecol 2006 Jun;58(3):227-31.
  3. dios Pozo-Olano J, Warram JH, Jr., Gomez RG, et al. Effect of a lactobacilli preparation on traveler's diarrhea. A randomized, double blind clinical trial. Gastroenterology 1978;74(5 Pt 1):829-830.
  4. Fedorak RN, Madsen KL. Probiotics and the management of inflammatory bowel disease. Inflamm.Bowel Dis 2004;10(3):286-299.
  5. Gotteland M, Poliak L, Cruchet S, et al. Effect of regular ingestion of Saccharomyces boulardii plus inulin or Lactobacillus acidophilus LB in children colonized by Helicobacter pylori. Acta Paediatr 2005 Dec;94(12):1747-51.
  6. Hilton E, Isenberg HD, Alperstein P, et al. Ingestion of yogurt containing Lactobacillus acidophilus as prophylaxis for candidal vaginitis. Ann Intern Med 1992;116(5):353-357.
  7. Ishida Y, Nakamura F, Kanzato H, et al. Clinical effects of Lactobacillus acidophilus strain L-92 on perennial allergic rhinitis: a double-blind, placebo-controlled study. J Dairy Sci 2005;88(2):527-533.
  8. Kliegman RM, Willoughby RE. Prevention of necrotizing enterocolitis with probiotics. Pediatrics 2005;115(1):171-172.
  9. Saggioro, A. Probiotics in the treatment of irritable bowel syndrome. J Clin Gastroenterol 2004;38(6 Suppl):S104-S106.
  10. Salazar-Lindo E, Figueroa-Quintanilla D, et al.. Effectiveness and safety of Lactobacillus LB in the treatment of mild acute diarrhea in children. J Pediatr Gastroenterol Nutr 2007 May;44(5):571-6.
  11. Saltzman JR, Russell RM, Golner B, et al. A randomized trial of Lactobacillus acidophilus BG2FO4 to treat lactose intolerance. Am J Clin Nutr 1999;69(1):140-146.
  12. Sazawal S, Hiremath G, Dhingra U, et al. Efficacy of probiotics in prevention of acute diarrhoea: a meta-analysis of masked, randomised, placebo-controlled trials. Lancet Infect Dis 2006 Jun;6(6):374-82.
  13. Taylor AL, Dunstan JA, Prescott SL. Probiotic supplementation for the first 6 months of life fails to reduce the risk of atopic dermatitis and increases the risk of allergen sensitization in high-risk children: a randomized controlled trial. J Allergy Clin Immunol 2007 Jan;119(1):184-91.
  14. Vivatvakin B, Kowitdamrong E. Randomized control trial of live Lactobacillus acidophilus plus Bifidobacterium infantis in treatment of infantile acute watery diarrhea. J Med Assoc Thai 2006 Sep;89 Suppl 3:S126-33.
  15. Xiao SD, Zhang de Z, Lu H, et al. Multicenter, randomized, controlled trial of heat-killed Lactobacillus acidophilus LB in patients with chronic diarrhea. Adv Ther 2003;20(5):253-260.

February 01, 2008.

Natural Standard Logo This evidence-based monograph was prepared by the Natural Standard Research Collaboration. The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. Talk to your health care provider before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Copyright© 2008 Natural Standard ( All Rights Reserved.