Quick summary

Lactobacillus johnsonii is a probiotic bacterial strain belonging to the Lactobacillus genus. It is commonly found in the human gut and other mucosal surfaces. This probiotic is under research for its potential effects on gut microbiota modulation and intestinal health support. However, evidence regarding its efficacy and safety in humans remains limited and inconclusive at this time.

What is it?

Lactobacillus johnsonii is a species of Lactobacillus bacteria naturally inhabiting the human gastrointestinal tract and other mucosal sites. It is often included in probiotic supplements aimed at promoting a healthy balance of gut microbes and maintaining intestinal homeostasis.

How it may work in the body

Proposed mechanisms for how Lactobacillus johnsonii may influence health include:

  • Modulation of gut microbiome composition by promoting beneficial bacteria
  • Competitive inhibition of potentially harmful pathogenic bacteria
  • Possible interaction with the immune system at mucosal surfaces, supporting immune modulation

These mechanisms are primarily derived from in vitro experiments, animal studies, and theoretical models. Direct evidence from human clinical trials confirming these modes of action is currently insufficient.

Common supplement forms

  • Capsules containing live Lactobacillus johnsonii cultures
  • Powders delivering probiotic bacteria
  • Fermented foods naturally containing live Lactobacillus species, including L. johnsonii

Typical dosage and how it is used

Currently, there is no established typical dosage for Lactobacillus johnsonii supplements supported by the supplied evidence. Specific dosages used in clinical studies were not provided. Furthermore, no official recommended daily intake (RDA) or adequate intake (AI) exists for this probiotic species.

Individuals interested in Lactobacillus johnsonii supplementation should refer to product-specific labeling or rely on dosing guidance from clinical trials once more data become available.

Natural sources

  • Human gastrointestinal tract represents the main natural reservoir of Lactobacillus johnsonii
  • Fermented dairy products may contain various Lactobacillus strains, sometimes including L. johnsonii

Absorption and bioavailability

As a probiotic bacterium, Lactobacillus johnsonii is intended to survive transit through the acidic environment of the stomach and reach the intestines, where it may transiently colonize or inhabit the gut mucosa. Specific data comparing bioavailability from different supplement formulations or identifying factors that enhance or inhibit survival and colonization are not available from the current evidence.

Potential benefits: what does the evidence say?

Area: Gut microbiota modulation and intestinal health

  • Evidence level: Insufficient
  • Human evidence summary: Research on Lactobacillus johnsonii’s health effects is ongoing, but no conclusive human clinical evidence presently demonstrates specific benefits of supplementation.
  • Limitations: The absence of published human clinical trials or systematic reviews limits the ability to establish efficacy or make clear efficacy statements.

Overall, while Lactobacillus johnsonii has theoretical potential to support gut health, more rigorous human research is needed to confirm any benefits.

Side effects and safety

No specific side effects or adverse reactions have been consistently reported in the literature for Lactobacillus johnsonii supplementation. There is also no documented evidence on contraindications or toxicity associated with its use. However, comprehensive safety data are lacking.

As with all probiotics, some individuals may experience mild gastrointestinal symptoms such as bloating or gas, but no data specific to this strain were supplied.

Drug and supplement interactions

No interactions between Lactobacillus johnsonii and pharmaceuticals or other supplements have been documented in the supplied evidence. Nevertheless, a consult with a healthcare professional is advisable before combining probiotics with medications or other supplements.

Who should be careful?

People with weakened immune systems, underlying health conditions, or those receiving immunosuppressive therapy should exercise caution when considering probiotic supplements, including Lactobacillus johnsonii, due to limited safety data.

Pregnancy, breastfeeding and special populations

There are no specific safety data available regarding the use of Lactobacillus johnsonii during pregnancy or breastfeeding. Individuals who are pregnant, breastfeeding, have medical conditions, use medication, or are planning surgery should consult a healthcare professional before starting this or any supplement.

Quality, standardization and what to look for

When choosing a Lactobacillus johnsonii supplement, consider the following:

  • Products that guarantee live bacterial counts until the expiry date (CFU counts)
  • Manufacturers that follow Good Manufacturing Practices (GMP) for probiotics
  • Third-party testing or certification confirming strain identity and purity
  • Clear labeling of the probiotic strain and dose per serving

Because probiotic viability can be affected by storage conditions, consider storage instructions (e.g., refrigeration) when purchasing.

Frequently asked questions

  • Can Lactobacillus johnsonii prevent or cure illnesses?
    There is currently no strong human evidence to support that Lactobacillus johnsonii can treat, prevent, or cure any disease.
  • Is Lactobacillus johnsonii different from other Lactobacillus probiotics?
    Yes, L. johnsonii is a distinct species within the Lactobacillus genus and may have different properties than other probiotic strains, though research on its unique effects is limited.
  • How long does it take to see effects from L. johnsonii supplements?
    Because human data are lacking, the timeline to any potential effect is unclear.
  • Are there any risks combining Lactobacillus johnsonii with antibiotics?
    No specific risks are documented, but antibiotics may reduce probiotic effectiveness by killing beneficial bacteria. Always consult a healthcare provider when using both.
  • What is the best way to store these probiotics?
    Follow manufacturer recommendations, which often suggest refrigeration to maintain viability.

Evidence limitations

  • No human clinical trial results or systematic reviews provided in the currently supplied evidence
  • Insufficient data on dosing, safety, and efficacy in humans
  • Lack of official recommended intake values or authorized EU health claims

References

Last reviewed

June 2024

Disclaimer: This page is for informational purposes only and does not constitute medical advice. Lactobacillus johnsonii supplements have not been authorized in the EU for specific health claims according to the supplied evidence. Consult a healthcare professional before beginning any new supplement, especially if pregnant, breastfeeding, having a medical condition, using medication, or planning surgery.