Supplement
Lactobacillus acidophilus is a friendly bacterium that lives naturally in the gut and vagina, where it produces lactic acid and helps keep the microbial community in balance. Most people look at it for antibiotic-associated diarrhea, and human trials found fewer cases of it, with moderate evidence behind that result. Many of those trials used it alongside other Lactobacillus strains, and research on gut inflammation, immunity and cholesterol comes mostly from animal or lab studies.
Sources: PMID 29702133
- Updated
- How we grade
- 20 studies cited
- Best evidence
- Grade B
- Conditions studied
- 7
- Outcomes
- 12
- Graded outcomes
- 0354
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Atopic Dermatitis Symptoms Three clinical trials using the L. acidophilus L-92 strain demonstrated improvements in atopic dermatitis symptoms. A double-blind RCT in Japanese adults and a pediatric study both showed reductions in dermatitis severity scores and serum cytokine markers. A third trial demonstrated efficacy with prolonged ingestion of L-92 in adult patients. | Improves (the measure goes down) | Small effect | 4 studies | 250 people | ||
Studies that measured atopic dermatitis symptoms
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| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Acute Diarrhea Symptoms Multiple human trials support L. acidophilus for treatment of acute diarrhea. An RCT in children hospitalized with acute diarrhea found that an L. acidophilus mixture reduced symptom duration and severity. The overall evidence for diarrhea treatment is described as reasonably good across multiple clinical studies. | Improves (the measure goes down) | Moderate effect | 2 studies | 400 people | ||
Antibiotic-Associated Diarrhea (AAD)
- Antibiotic-Associated Diarrhea Risk: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Antibiotic-Associated Diarrhea Risk Multiple human trials demonstrate L. acidophilus, often in combination with other Lactobacillus strains, reduces the incidence of antibiotic-associated diarrhea. A systematic assessment of evidence for a specific probiotic combining L. acidophilus, L. casei, and L. rhamnosus supported primary prevention of C. difficile-associated diarrhea in antibiotic users. | Improves (the measure goes down) | Moderate effect | 2 studies | 500 people | ||
Studies that measured antibiotic-associated diarrhea risk | ||||||
General
- Immune Function: improves
- Intestinal Inflammation: improves
- Pathogen Virulence Inhibition: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Immune Function Animal studies demonstrate L. acidophilus enhances immune function, including improved immune response to Newcastle disease vaccination in chickens and enhanced skin mucosal immune parameters in fish models. In vitro studies show interaction with intestinal epithelial M cells and modulation of immunomodulatory activity, supporting a plausible mechanism for immune enhancement. | Improves (the measure goes up) | Small effect | 5 studies | |||
Studies that measured immune function
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| Intestinal Inflammation Multiple animal studies show L. acidophilus attenuates intestinal inflammation. It reduced Salmonella-induced intestinal inflammation via TGF-β signaling and alleviated goblet cell loss and colitis through Notch pathway modulation in rodent models. L. acidophilus XY27 also showed preventive effects against DSS-induced ulcerative colitis in mice. | Improves (the measure goes down) | Moderate effect | 4 studies | |||
Studies that measured intestinal inflammation
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| Pathogen Virulence Inhibition In vitro studies show L. acidophilus attenuates toxin production by Vibrio cholerae and Shigella dysenteriae following intestinal epithelial cell infection. Preclinical data also demonstrate modulation of C. difficile virulence. These findings support antimicrobial mechanisms but lack human clinical validation. | Changes; see studies | Moderate effect | 3 studies | |||
Studies that measured pathogen virulence inhibition
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| Urinary Oxalate Levels A randomized, placebo-controlled, double-blind trial evaluated a probiotic containing L. acidophilus and Bifidobacterium animalis lactis on urine oxalate in calcium stone formers with hyperoxaluria. The combination product showed some effect on oxalate excretion, supported by in vitro oxalate degradation data. | Changes; see studies | Small effect | 2 studies | 40 people | ||
Studies that measured urinary oxalate levels
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| Infantile Colic Symptoms An open randomized controlled trial found that a combination of Matricariae chamomilla, Melissa officinalis, and tyndallized L. acidophilus (HA122) was effective in reducing infantile colic symptoms. However, this was an open-label design with a multi-component intervention, limiting conclusions about L. acidophilus alone. | Improves (the measure goes down) | Small effect | 2 studies | 176 people | ||
Studies that measured infantile colic symptoms
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C. difficile
- C. difficile Infection Risk: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| C. difficile Infection Risk A review of clinical evidence assessed the use of a specific probiotic combining L. acidophilus with L. casei and L. rhamnosus for primary prevention of C. difficile infections, finding supportive evidence. Preclinical work showed L. acidophilus modulates the virulence of C. difficile in vitro, providing mechanistic support. | Improves (the measure goes down) | Moderate effect | 3 studies | 300 people | ||
Studies that measured c. difficile infection risk
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Cardiovascular Health
- Cholesterol Levels: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cholesterol Levels In dyslipidemic rat models, L. acidophilus supplementation demonstrated potential benefits on lipid profiles. Limited human evidence suggests possible modest cholesterol-lowering effects, though effect sizes are small. The mechanism may involve bile salt hydrolase activity and cholesterol assimilation by the probiotic. | Improves (the measure goes down) | Small effect | 2 studies | |||
Bacterial Vaginosis (BV)
- Vaginal Health: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Vaginal Health L. acidophilus is a natural constituent of vaginal flora and has moderate evidence supporting its use for vaginal health. Studies confirm mother-to-child transmission of L. acidophilus at delivery. Clinical use for bacterial vaginosis prevention is supported by its colonization capacity, though large RCTs specific to L. acidophilus alone are limited. | Improves (the measure goes up) | Small effect | 2 studies | |||
Arthritis (Multiple Kinds)
- Osteoarthritis Pain and Cartilage Degradation: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Osteoarthritis Pain and Cartilage Degradation A single animal study found that L. acidophilus ameliorated pain and cartilage degradation in an experimental osteoarthritis model, suggesting potential anti-inflammatory effects on joint tissue. No human clinical trials have been reported for this indication. | Improves (the measure goes down) | Moderate effect | 2 studies | |||
Studies that measured osteoarthritis pain and cartilage degradation | ||||||
Key findings
- Atopic Dermatitis SymptomsImproves (the measure goes down)
- Acute Diarrhea SymptomsImproves (the measure goes down)
- Antibiotic-Associated Diarrhea RiskImproves (the measure goes down)
Safety notes in the studies
- In vitro studies show interaction with intestinal epithelial M cells and modulation of immunomodulatory activity, supporting a plausible mechanism for immune enhancement.
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Third-party tested Lactobacillus acidophilus products, in the forms the graded studies used where we can match them.
- Grade B
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Studies cited
20 studies from PubMed
- Potential benefits of L. acidophilus in dyslipidemic rats
- Effect of a Probiotic Supplement Containing Lactobacillus Acidophilus and Bifidobacterium Animalis Lactis on Urine Oxalate in Calcium Stone Formers with Hyperoxaluria: A Randomized, Placebo-controlled, Double-blind and In-vitro Trial
- Preventive Effect of Lactobacillus acidophilus XY27 on DSS-Induced Ulcerative Colitis in Mice
- Immune enhancing effects of Lactobacillus acidophilus on Newcastle disease vaccination in chickens
- Lactobacillus acidophilus attenuates toxin production by Vibrio cholerae and shigella dysenteriae following intestinal epithelial cells infection
- Primary prevention of Clostridium difficile infections with a specific probiotic combining Lactobacillus acidophilus, L. casei, and L. rhamnosus strains: assessing the evidence
- Lactobacillus acidophilus Alleviated Salmonella-Induced Goblet Cells Loss and Colitis by Notch Pathway
- Lactobacillus acidophilus ameliorates pain and cartilage degradation in experimental osteoarthritis
- Efficacy of a standardized extract of Matricariae chamomilla L., Melissa officinalis L. and tyndallized Lactobacillus acidophilus (HA122) in infantile colic: An open randomized controlled trial
- Uromodulin-SlpA binding dictates Lactobacillus acidophilus uptake by intestinal epithelial M cells
- Lactobacillus acidophilus Mixture in Treatment of Children Hospitalized With Acute Diarrhea
- Efficacy of prolonged ingestion of Lactobacillus acidophilus L-92 in adult patients with atopic dermatitis
- Lactobacillus acidophilus attenuates Salmonella-induced intestinal inflammation via TGF-β signaling
- The effects of Lactobacillus acidophilus as feed supplement on skin mucosal immune parameters, intestinal microbiota, stress resistance and growth performance of black swordtail
- Lactobacillus acidophilus CP23 with weak immunomodulatory activity lacks anchoring structure for surface layer protein
- Lactobacillus acidophilus modulates the virulence of Clostridium difficile
- Effects of oral administration of Lactobacillus acidophilus L-92 on the symptoms and serum cytokines of atopic dermatitis in Japanese adults: a double-blind, randomized, clinical trial
- Effects of oral administration of Lactobacillus acidophilus L-92 on the symptoms and serum markers of atopic dermatitis in children
- Probiotic Lactobacillus acidophilus and L. casei mix sensitize colorectal tumoral cells to 5-fluorouracil-induced apoptosis
- Transmission of Lactobacillus jensenii and Lactobacillus acidophilus from mother to child at time of delivery