Lactococcus acidiphilus W22
Also known as: Lactococcus acidophilus W22, L. acidophilus, Lactobacillus acidophilus W22, Lactobacillus acidophilus
Overview
Lactobacillus acidophilus is a Gram-positive, rod-shaped, homofermentative anaerobic bacterium commonly found in the human gastrointestinal tract, oral cavity, and vagina. It primarily ferments carbohydrates into lactic acid. The W22 strain is a specific isolate within the L. acidophilus species, marketed as a probiotic supplement to support gut health and modulate immune responses. Its main applications include the prevention and treatment of antibiotic-associated diarrhea (AAD) and the modulation of gut microbiota. While extensive research, including numerous randomized controlled trials (RCTs) and meta-analyses, supports the efficacy of L. acidophilus as a species, strain-specific data for W22 is limited. Evidence quality for the species is high, with systematic reviews and meta-analyses consistently demonstrating its benefits in certain gastrointestinal conditions.
Benefits
The primary benefit of Lactobacillus acidophilus, particularly when administered alone or in combination with other probiotics, is the reduction in the incidence and severity of antibiotic-associated diarrhea (AAD). Meta-analyses have shown significant relative risk reductions for AAD, ranging from 33% to 44%, with consistent statistical significance across multiple RCTs. For instance, combinations including L. acidophilus CL1285 have demonstrated a relative risk of 0.56 (95% CI 0.40–0.79) for AAD. This benefit is clinically relevant and most pronounced in adults undergoing antibiotic therapy. Additionally, L. acidophilus contributes to the improvement of gut microbiota balance and can alleviate general gastrointestinal symptoms like diarrhea. Secondary effects include the modulation of inflammatory cytokines, such as IL-6, IL-8, and IL-10, observed in some studies on athletes post-exercise, though these results are mixed and often lack statistical significance. The benefits for AAD prevention are typically observed during and shortly after antibiotic treatment, while immune modulation effects may require longer supplementation.
How it works
Lactobacillus acidophilus exerts its probiotic effects primarily by producing lactic acid, which lowers the intestinal pH. This acidic environment inhibits the growth of pathogenic bacteria, thereby contributing to a healthier gut microbiome. The bacterium also interacts directly with the gut mucosal immune system, influencing the production of various cytokines and potentially enhancing the integrity of the intestinal barrier. Its molecular targets include epithelial cells lining the gut and immune cells within the gut-associated lymphoid tissue (GALT). As a probiotic, L. acidophilus acts locally within the gut lumen; therefore, systemic absorption is not applicable. Its ability to colonize the gut varies depending on the specific strain.
Side effects
Lactobacillus acidophilus is generally recognized as safe (GRAS) and has a long history of use in food products and dietary supplements. Common side effects are typically mild and transient, primarily involving gastrointestinal symptoms such as bloating or gas, which affect less than 5% of users. Serious adverse events are exceedingly rare. However, in severely immunocompromised individuals or those with central venous catheters, there have been isolated reports of infections, though these occurrences are extremely uncommon. No significant drug interactions have been consistently reported. Contraindications include caution in severely immunocompromised patients due to the theoretical risk of bacteremia, and in individuals with central venous catheters where the risk of systemic infection might be elevated.
Dosage
Effective dosages of Lactobacillus acidophilus in clinical studies typically range from 1 × 10^9 to 1 × 10^10 Colony Forming Units (CFU) per day, particularly for the prevention of antibiotic-associated diarrhea (AAD). The optimal dose can vary depending on the specific strain and the formulation of the supplement. When used for AAD prevention, it is generally recommended to administer L. acidophilus concurrently with the antibiotic treatment and to continue supplementation for several days after the antibiotic course is completed. L. acidophilus is available in various forms, including capsules, powders, and fermented dairy products. The efficacy of the supplement is influenced by the formulation's ability to protect the bacteria from gastric acid, ensuring a sufficient number of viable organisms reach the intestines. While prebiotics like inulin may enhance colonization, they are not strictly necessary for the probiotic's effectiveness.
FAQs
Is Lactococcus acidophilus W22 safe?
Yes, Lactococcus acidophilus W22, or more accurately Lactobacillus acidophilus, is generally considered safe for healthy individuals, with minimal and transient side effects like mild bloating or gas.
When should it be taken?
It is ideally taken during antibiotic therapy to help prevent antibiotic-associated diarrhea, and often continued for a short period after the antibiotic course ends.
How soon will benefits appear?
Benefits related to diarrhea prevention are typically observed within days to weeks of starting supplementation. Immune modulation effects, if any, may require longer-term use.
Is it effective alone or only in combination?
Both. Some strains of Lactobacillus acidophilus are effective on their own, but combinations with other probiotic strains often demonstrate enhanced or broader benefits.
Research Sources
- https://www.frontiersin.org/journals/gastroenterology/articles/10.3389/fgstr.2022.983075/full – This systematic review and meta-analysis found that L. acidophilus, particularly when combined with L. bulgaricus, significantly reduced the incidence of diarrhea compared to placebo. The study highlighted the statistical significance of these findings, despite some heterogeneity in the included studies and populations.
- https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2018.00124/full – This meta-analysis focused on adults taking antibiotics and concluded that probiotic mixtures, including L. acidophilus strains, effectively reduced the risk of antibiotic-associated diarrhea (AAD). It reported relative risk reductions ranging from 0.56 to 0.67, noting moderate heterogeneity and emphasizing the importance of strain-specific data, though specific data for W22 was limited.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC12098250/ – This systematic review and meta-analysis investigated the effects of probiotics on cytokine modulation in athletes. It found mixed and inconsistent effects on inflammatory markers post-exercise, with no consistent significant changes. The study's findings were preliminary due to small sample sizes and its focus on a specific athletic population.
- https://en.wikipedia.org/wiki/Lactobacillus_acidophilus – This source provides a general overview of Lactobacillus acidophilus, describing it as a Gram-positive, rod-shaped bacterium found in the human gastrointestinal tract, oral cavity, and vagina. It notes its role in fermenting carbohydrates into lactic acid.
- https://scholarworks.montana.edu/server/api/core/bitstreams/6785e0ff-a341-4e81-8a79-f42fe1c5c868/content – This source provides additional context regarding the distinction between Lactococcus and Lactobacillus genera, clarifying potential taxonomic confusion. It underscores that while Lactobacillus acidophilus is a well-studied species, specific data on the W22 strain may be proprietary or less extensively published in peer-reviewed literature.
