A Probiotic Isolated From Wasabi Plants Cut Lactose Intolerance Symptoms in Mice

Lactose intolerance is one of the most widespread digestive complaints on the planet, affecting an estimated 65 to 75% of adults worldwide, with rates climbing even higher in Asian and African populations. Most people manage it by avoiding dairy or using over-the-counter lactase supplements, neither of which works reliably for everyone. A new study published in June 2026 in the journal Microorganisms points to a different option: a specific probiotic strain isolated from wasabi plants that, in early mouse experiments, reduced multiple hallmarks of lactose intolerance simultaneously.

Lactiplantibacillus plantarum A458 and Its Effect on Lactose Digestion

The study by Zhang R, Danshiitsoodol N, Noda M, and Sugiyama M. focused on a strain called Lactiplantibacillus plantarum A458, sourced from Wasabia japonica, the plant behind the pungent green paste on your sushi plate. Before any animal experiments, the team put A458 through a battery of in vitro tests. The strain survived at pH 2.0 with 47% viability, handled a 0.3% bile salt environment with 85% survival, and produced roughly 33 mM of lactic acid while fermenting lactose in modified growth media. It also adhered to human intestinal Caco-2 cells at a rate of 7.47% and, notably, reduced invasion by Listeria monocytogenes by 67.28%. Those numbers matter because research on Lactiplantibacillus plantarum broadly has linked acid and bile tolerance to the ability of a strain to survive transit through the gastrointestinal tract and reach the gut in a metabolically active state.

When the researchers moved to a mouse model of lactose intolerance, induced by feeding animals a 30% lactose solution, A458 performed well on the primary outcome: jejunal lactase activity. Lactase is the enzyme that breaks lactose into absorbable sugars, and its deficiency is the root cause of intolerance. Mice in the lactose-intolerance group showed significantly lower jejunal lactase activity than healthy controls. Administration of A458 at 1 x 10^9 CFU per mouse per day significantly increased that activity, while also improving body weight and stool consistency throughout the intervention.

Inflammation and Oxidative Stress as Overlooked Targets

Lactose maldigestion is not just a plumbing problem. When undigested lactose reaches the colon, it ferments, and the byproducts can tip the gut toward inflammation. The LI mice in this study showed elevated serum levels of interleukin-6, TNF-alpha, and IL-1beta, a classic signature of systemic low-grade inflammation. A458 administration significantly reduced serum IL-6 and TNF-alpha, which the authors suggest may involve inhibition of NF-kB signaling, a pathway that several Lactobacillus-derived probiotics have been reported to suppress.

The redox angle is less familiar and arguably more interesting. The liver of LI mice showed reduced superoxide dismutase (SOD) activity, elevated malondialdehyde (MDA, a marker of lipid peroxidation), and a lower glutathione-to-oxidized-glutathione ratio (GSH/GSSG). These markers collectively indicate oxidative stress. A458 reversed all three: SOD activity increased, MDA decreased, and the GSH/GSSG ratio improved. The probable pathway, the authors propose, runs through Nrf2, a transcription factor that governs antioxidant gene expression. These mechanistic claims remain to be validated experimentally, but the biomarker data in the mice were statistically significant.

How the Microbiome Shifted After A458 Treatment

The team analyzed gut microbiota composition from jejunal and ileal samples using 16S rRNA gene sequencing. Heatmap analysis revealed distinct microbial distribution patterns across experimental groups. In LI mice treated with A458, the relative abundances of Lactobacillus, Allobaculum, and Turicibacter increased, while Bacteroides, Prevotella, Parabacteroides, Escherichia, and Sutterella decreased. The direction of those shifts is consistent with a healthier gut environment: the genera that declined are associated with intestinal stress and dysbiosis, while those that increased are generally considered beneficial in rodent models.

However, this is where caution is warranted. The microbiota data are relative abundance measurements from 16S rRNA sequencing, which means they describe proportional shifts, not absolute changes in microbial load. Probiotics research combining Bifidobacterium and Lactiplantibacillus strains has shown that diarrhea and flatulence reduction in lactose intolerance can be real even when the underlying microbiome story is complicated. Still, interpreting microbiota shifts as causal requires more than abundance correlations.

Key Limitations Before This Reaches Any Clinic

This is early-stage, investigational research, and the limitations are real. Each experimental group contained only five mice, a sample size that constrains statistical power and reproducibility. No dose-response experiment was run, so it is unknown whether a lower or higher CFU count would have performed differently. There was no comparison arm using a standard treatment such as exogenous lactase, which would have given the results clinical context.

Most critically, the entire study was conducted in mice. Mouse models are valuable tools for studying host-microbe interactions, but the rodent gut differs substantially from the human gut in anatomy, microbial composition, and immune physiology. Variation in gut microbiome across animal facilities and housing conditions can also affect how reproducible disease-model phenotypes are. The molecular mechanisms proposed, NF-kB suppression and Nrf2 activation, were inferred from biomarker patterns, not from direct pathway measurement. Validating them would require additional experiments.

What Comes Next for Probiotic-Based Lactose Intolerance Therapy

The researchers call for human clinical trials as the obvious next step, along with dose-response work and direct mechanistic validation. The case for A458 specifically rests on a set of characteristics that distinguish it from generic Lactobacillus preparations: its origin in an edible plant with known antimicrobial properties, its dual action on both lactase activity and oxidative stress markers, and its suppression of a clinically significant pathogen in cell culture. Whether those advantages persist in a human gut, with its enormous individual variability in microbiome composition and immune status, is the question that needs answering.

For the roughly two-thirds of adults globally who manage some degree of lactose intolerance, a probiotic that works on multiple fronts at once would be a meaningful advance. This study is a credible first step, not a finished answer.

Evidence rating

INVESTIGATIONAL — 75/100

Caveats:

• This study was conducted entirely in mice (n=5 per group); whether these effects translate to humans is unknown.
• The very small group sizes (n=5) limit statistical reliability.
• No dose-response testing and no comparison to standard lactose intolerance therapies were performed.
• Funding source was not disclosed by the authors.

Combined in vitro and mouse-model study (n=5 per group) testing a single probiotic strain for lactose intolerance. Results show associations between oral L. plantarum A458 administration and improved lactase activity, reduced inflammatory cytokines, and gut microbiota shifts, but the animal-only design and very small group sizes limit causal inference and generalizability. The findings have not been replicated in human populations.

References

1. Rentao Zhang, Narandalai Danshiitsoodol, Masafumi Noda, Masanori Sugiyama (2026). Effects of Lactiplantibacillus plantarum A458 on Lactose Intolerance in Mice: Associations with Gut Microbiota and Redox Balance. Microorganisms. https://doi.org/10.3390/microorganisms14061273
2. Yu Hao, Jianli Li, Jicheng Wang, Yongfu Chen (2024). Mechanisms of Health Improvement by Lactiplantibacillus plantarum Based on Animal and Human Trials: A Review. Fermentation. https://doi.org/10.3390/fermentation10020073
3. Tsachi Tsadok Perets, Rachel Gingold-Belfer, Ram Dickman (2026). Lactose intolerance and probiotics: from pathophysiological mechanisms to clinical applications. Antonie van Leeuwenhoek. https://doi.org/10.1007/s10482-026-02278-x
4. Thi Loan Anh Nguyen, Sara Vieira-Silva, Adrian Liston, Jeroen Raes (2015). How informative is the mouse for human gut microbiota research?. Disease Models & Mechanisms. https://doi.org/10.1242/dmm.017400
5. Consideration of Gut Microbiome in Murine Models of Diseases – MDPI. mdpi.com. https://www.mdpi.com/2076-2607/9/5/974