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Lactobacillus animalis lactis

Also known as: Bifidobacterium animalis subsp. lactis, B. lactis, BB-12®, HN019

Overview

Bifidobacterium animalis subsp. lactis, commonly known as B. lactis, is a gram-positive, anaerobic bacterium widely used as a probiotic. It is naturally found in fermented dairy products like yogurt and kefir, as well as being added to infant formulas and probiotic supplements. B. lactis is primarily used to promote gut health, modulate the immune system, and prevent antibiotic-associated diarrhea (AAD). Its efficacy has been evaluated in numerous clinical trials, systematic reviews, and meta-analyses, demonstrating moderate-to-high evidence for specific applications, particularly in AAD prevention. Different strains, such as BB-12® and HN019, may exhibit varying effects, necessitating strain-specific considerations. Overall, B. lactis is a well-researched probiotic with a generally recognized safety profile.

Benefits

B. lactis has demonstrated several evidence-based benefits. It is effective in preventing antibiotic-associated diarrhea (AAD), with a relative risk (RR) of 0.67 (95% CI 0.47–0.94) when combined with L. acidophilus La5 in adults, resulting in a number needed to treat (NNT) of approximately 7. Furthermore, B. lactis, particularly the HN019 strain, enhances immune function by increasing natural killer (NK) cell activity and neutrophil phagocytosis in elderly adults. This may reduce the frequency of respiratory infections in vulnerable populations. In premature infants, a combination of B. lactis and L. rhamnosus GG has been shown to decrease the time to regain birth weight and improve tolerance to enteral nutrition.

How it works

B. lactis exerts its beneficial effects through several mechanisms. It enhances the gut barrier by modulating tight junction proteins like occludin and ZO-1, thereby improving gut integrity. Immunomodulation is achieved by activating TLR2/4 pathways, leading to increased production of IL-10, an anti-inflammatory cytokine. Additionally, B. lactis enhances the phagocytic activity of neutrophils and monocytes, key components of the innate immune system. It also modulates the microbiome by competing with pathogens for adhesion sites, preventing their colonization and proliferation within the gut.

Side effects

B. lactis is generally considered safe, holding Generally Recognized as Safe (GRAS) status. Common side effects are mild and infrequent, primarily including bloating and gas, reported in less than 5% of clinical trial participants. However, rare cases of bacteremia have been reported in severely immunocompromised patients. B. lactis is contraindicated in individuals with short bowel syndrome, those with central venous catheters, and those with severe immunosuppression. While generally safe, caution is advised in vulnerable populations, and any adverse reactions should be promptly reported to a healthcare provider.

Dosage

The minimum effective dose of B. lactis ranges from 1 to 10 billion CFU per day, with an optimal range of 10 to 100 billion CFU per day. It is recommended to take B. lactis with meals to protect it from gastric acid. Strain-specific dosages vary; for instance, the HN019 strain is used at 10 billion CFU per day for immune support, while BB-12 is used at 1 to 10 billion CFU per day for gut health. While specific upper limits are not well-defined, exceeding recommended dosages may increase the risk of gastrointestinal discomfort. Always follow product-specific instructions and consult with a healthcare provider for personalized recommendations.

FAQs

When can I expect to see results?

Immune effects may be noticeable within 2–4 weeks, while improvements in antibiotic-associated diarrhea prevention can be observed within 1 week.

Does B. lactis need to be refrigerated?

Refrigeration requirements are strain-dependent. BB-12, for example, is shelf-stable in freeze-dried forms, but other strains may require refrigeration to maintain viability.

What is the best way to pair B. lactis with other supplements?

B. lactis demonstrates synergistic effects with L. rhamnosus GG for promoting gut health, making them a beneficial combination.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/32059116/ – This study investigates the impact of probiotics on gut health. It provides insights into the mechanisms through which probiotics like B. lactis can influence the gut microbiome and overall digestive wellness, highlighting potential therapeutic applications.
https://pubmed.ncbi.nlm.nih.gov/28245559/ – This research explores the effects of B. lactis HN019 on immune function in elderly adults. The study demonstrates that HN019 enhances natural killer cell activity, suggesting its potential to bolster immune responses in vulnerable populations.
https://www.mdpi.com/2072-6643/9/3/191 – This paper reviews the immunomodulatory effects of probiotics, including B. lactis. It discusses how these probiotics interact with the immune system to enhance immune responses and maintain immune homeostasis, providing a comprehensive overview of their mechanisms of action.
https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2018.00124/full – This meta-analysis examines the efficacy of B. lactis and L. acidophilus in preventing antibiotic-associated diarrhea (AAD). The analysis of six RCTs involving over 1,200 adults showed a significant reduction in AAD risk with the probiotic combination, though it did not isolate strain-specific effects.
https://www.scielo.br/j/ramb/a/h7R5DfmV6XnzbYgDKcTFQcQ/ – This retrospective study evaluates the impact of B. lactis BB-12 combined with L. rhamnosus GG on premature infants. The study found that the probiotic combination reduced the time to full enteral feeding, suggesting improved tolerance and nutritional outcomes in this vulnerable population, though the observational design limits causal inferences.