Lactobacillus Acidophilus W22
Also known as: Lactobacillus acidophilus, probiotic bacteria, Lactobacillus acidophilus W22
Overview
Lactobacillus acidophilus W22 is a specific strain of beneficial bacteria belonging to the species *Lactobacillus acidophilus*, which is naturally found in the human gut and various fermented foods. As a probiotic, it is primarily utilized in supplements to support gastrointestinal health. While the broader species *L. acidophilus* has extensive research supporting its efficacy in improving gut health, preventing or treating diarrhea, and modulating the immune system, strain-specific data for W22 are more limited. Its main applications include the management and prevention of antibiotic-associated diarrhea (AAD) and acute gastroenteritis. The evidence base for *L. acidophilus* as a species is robust, with numerous randomized controlled trials and meta-analyses, indicating moderate-quality evidence for its benefits when administered at sufficient doses.
Benefits
Meta-analyses indicate that *Lactobacillus acidophilus* species can reduce the duration and frequency of diarrhea in children with acute gastroenteritis, particularly at doses of 10^9 CFU/day or higher, though the effects can be modest when used alone. Probiotic mixtures containing *L. acidophilus* strains have demonstrated significant reductions in the risk of antibiotic-associated diarrhea (AAD), with relative risk reductions ranging from 33% to 44% in adults. These benefits are clinically relevant for populations such as children experiencing acute gastroenteritis and adults at risk of AAD. The efficacy is often strain- and disease-specific, with mixtures including *L. acidophilus* W22 or related strains showing promise in gastrointestinal symptom management. Benefits are typically observed within days to weeks of consistent administration, especially during or after antibiotic treatment or an acute infection.
How it works
*Lactobacillus acidophilus* W22 exerts its beneficial effects primarily by colonizing the gut mucosa, where it produces lactic acid. This process lowers the intestinal pH, creating an unfavorable environment for the growth of pathogenic bacteria. It also contributes to immune modulation by enhancing mucosal immunity and reducing inflammation within the gut. The bacteria interact with epithelial cells and immune cells in the gut-associated lymphoid tissue, influencing local and systemic immune responses. Its bioavailability is dependent on its ability to survive the harsh acidic conditions of the stomach and the presence of bile in the small intestine; encapsulation or delivery through fermented foods can significantly improve its viability and efficacy.
Side effects
*Lactobacillus acidophilus* W22 is generally considered safe for most individuals, including children and adults. The most common side effects, occurring in more than 5% of users, are mild gastrointestinal symptoms such as bloating or gas. Uncommon side effects, affecting 1-5% of users, may include mild allergic reactions. Very rare side effects, occurring in less than 1% of cases, involve systemic infections, primarily reported in severely immunocompromised or critically ill individuals; however, these instances are exceedingly rare. No significant drug interactions have been reported. Contraindications for its use include severe immunosuppression or critical illness, where administration should only occur under strict medical supervision.
Dosage
For optimal gastrointestinal benefits, the minimum effective dose of *Lactobacillus acidophilus* is generally considered to be 10^9 CFU (colony-forming units) per day. Optimal dosages can vary depending on the specific condition being addressed, but typically range from 10^9 to 10^11 CFU per day. The duration of supplementation usually spans from a few days to several weeks, depending on the indication, such as during antibiotic treatment or an acute illness. It is commonly available in various formulations, including capsules, powders, and incorporated into fermented dairy products. The efficacy and absorption of the probiotic can be enhanced by formulations that protect the bacteria from degradation by gastric acid.
FAQs
Is Lactobacillus acidophilus W22 effective alone?
While *L. acidophilus* species are effective, strain-specific efficacy for W22 requires more direct research. Benefits are often clearer when W22 is combined with other probiotic strains.
Is it safe for children?
Yes, studies support the safety and efficacy of *L. acidophilus* in pediatric acute gastroenteritis when administered at appropriate doses.
How soon do effects appear?
Effects typically begin to appear within a few days to a week after starting supplementation, depending on the individual and condition.
Can it prevent antibiotic-associated diarrhea?
Yes, especially when used in combination with other strains, *L. acidophilus* can significantly reduce the risk of antibiotic-associated diarrhea.
Research Sources
- https://www.frontiersin.org/journals/gastroenterology/articles/10.3389/fgstr.2022.983075/full – This systematic review and meta-analysis found that probiotic combinations, including *Lactobacillus acidophilus*, significantly reduced the incidence of diarrhea compared to placebo. It highlights the importance of probiotic combinations for efficacy but notes limitations in strain-specific data.
- https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0034938 – This meta-analysis on probiotics for gastrointestinal diseases emphasized that probiotics, including *Lactobacillus acidophilus*, are effective for several GI conditions. It underscored the critical role of appropriate dose and duration, acknowledging heterogeneity across species and strains.
- https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2018.00124/full – This meta-analysis focused on probiotic strain-specificity for antibiotic-associated diarrhea (AAD). It concluded that mixtures containing *Lactobacillus acidophilus* strains effectively reduced AAD risk, with relative risk reductions between 0.56 and 0.67, though attributing effects to W22 alone is challenging.
- https://www.semanticscholar.org/paper/A-Systematic-Review-and-Meta-Analysis:-acidophilus-Cheng-Ma/2d73fe56771e3971012bb7a9f4ff22b12169130c – This systematic review and meta-analysis of 15 RCTs involving 1765 children with acute gastroenteritis found that *Lactobacillus acidophilus* reduced diarrhea duration and frequency at doses of 10^9 CFU/day or more. The study noted moderate quality evidence and some heterogeneity, with limited strain-specific data.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8839062/ – This article, likely a duplicate or related to the Cheng et al. study, further supports the findings that *Lactobacillus acidophilus* can reduce diarrhea duration and frequency in children with acute gastroenteritis. It reinforces the moderate quality of evidence and the importance of dosage.
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