According to Gram Research analysis, probiotics did not improve intestinal permeability more than placebo in adults with MASH (metabolic dysfunction-associated steatohepatitis). In a 24-week randomized controlled trial of 44 patients, claudin-3 levels—a marker of intestinal leakiness—decreased equally in both the probiotic group (59% reduction) and placebo group (64% reduction), suggesting dietary changes rather than probiotics drove the improvement.
Researchers studied whether probiotics could help people with a serious liver condition called MASH (metabolic dysfunction-associated steatohepatitis). They gave some patients a probiotic mixture for 24 weeks while others got a placebo. Both groups showed improvement in a marker called claudin-3, which indicates how leaky their intestines were. However, the probiotic group didn’t improve more than the placebo group. This suggests that while probiotics are safe, they may not be the key to fixing intestinal problems in people with this liver disease.
Key Statistics
A 2026 randomized controlled trial of 44 adults with MASH found that probiotic supplementation reduced serum claudin-3 levels from 14.7 to 6.1 ng/mL over 24 weeks, but this 59% improvement was not significantly different from the 64% reduction in the placebo group.
In a secondary analysis of a randomized trial published in 2026, both probiotic and placebo groups reported reduced intake of calories, carbohydrates, proteins, and fats, but neither group showed significant changes in weight or waist circumference after 24 weeks.
A 2026 study of 44 MASH patients found that serum claudin-3 levels decreased significantly in both treatment groups (from 14.7 to 6.1 ng/mL in probiotics and 16.7 to 6.0 ng/mL in placebo), with no significant between-group difference, suggesting probiotics provided no additional benefit over placebo.
The Quick Take
- What they studied: Whether taking probiotics could reduce intestinal leakiness in people with a fatty liver disease called MASH
- Who participated: 44 adults with confirmed MASH (a serious liver condition) who completed a 24-week study comparing probiotics to placebo
- Key finding: Both the probiotic and placebo groups showed significant improvement in intestinal permeability markers (claudin-3 dropped from 14.7 to 6.1 ng/mL in the probiotic group and 16.7 to 6.0 ng/mL in placebo), with no meaningful difference between groups
- What it means for you: If you have MASH, probiotics alone may not be the answer for fixing intestinal problems. The improvement in both groups suggests other factors—like dietary changes both groups made—might be more important. Talk to your doctor before starting probiotics.
The Research Details
This was a secondary analysis of a randomized controlled trial, which is one of the strongest types of research studies. Researchers took data from a larger study where patients were randomly assigned to receive either a probiotic mixture (containing four types of beneficial bacteria) or a placebo (fake treatment) for 24 weeks. Neither the patients nor the researchers knew who got the real probiotics, which helps prevent bias.
The probiotic mixture contained four strains of bacteria commonly found in probiotic supplements: Lactobacillus acidophilus, L. rhamnosus, L. paracasei, and Bifidobacterium animalis. Patients took 2 sachets daily (1 × 10⁹ CFU, which is a measure of how many bacteria were in each dose). Researchers measured a protein called claudin-3 in the blood before and after treatment, which indicates how “leaky” the intestines are.
A secondary analysis means the researchers used data from an already-completed study to answer a new question. In this case, they focused specifically on how probiotics affected intestinal permeability in MASH patients.
This research design is important because randomized controlled trials are the gold standard for testing whether a treatment actually works. By randomly assigning people to groups and using a placebo, researchers can be more confident that any differences are due to the treatment itself, not other factors. The fact that both groups improved helps us understand whether probiotics are truly effective or if other changes (like diet) are responsible for improvement.
This study has several strengths: it was randomized and double-blind (reducing bias), it measured a specific biological marker (claudin-3) rather than just asking people how they felt, and it lasted 24 weeks (long enough to see real changes). However, the sample size was relatively small (44 patients), which limits how confident we can be about the results. The study also didn’t track what patients ate in detail, so we can’t be sure dietary changes were equal between groups.
What the Results Show
The main finding was that intestinal permeability improved significantly in both groups over 24 weeks, but probiotics didn’t provide extra benefit. In the probiotic group, claudin-3 levels dropped from 14.7 to 6.1 ng/mL (a 59% decrease). In the placebo group, levels dropped from 16.7 to 6.0 ng/mL (a 64% decrease). These improvements were nearly identical, suggesting the probiotic wasn’t responsible for the change.
Both groups also reported eating fewer calories, carbohydrates, proteins, and fats during the study. This dietary reduction happened in both groups equally, which is important because it suggests the improvement in intestinal permeability might have come from eating less overall, not from the probiotics themselves.
Neither group showed significant changes in weight or waist circumference, even though they ate less. This was surprising and suggests that the 24-week period might not have been long enough to see weight changes, or that the dietary changes weren’t large enough to affect body measurements.
The similar improvement in both groups is itself an important finding. It tells us that simply taking probiotics doesn’t automatically fix intestinal problems in MASH patients. The fact that the placebo group improved as much as the probiotic group suggests that other factors—possibly the act of being in a study, increased health awareness, or the dietary changes both groups made—may have been responsible for the improvement.
Previous research suggested that intestinal leakiness contributes to liver disease progression, and that probiotics might help seal up the intestines. This study challenges that assumption by showing probiotics don’t work better than placebo for this specific marker. However, this doesn’t mean probiotics are useless for all liver conditions—it just means they may not be the key solution for intestinal permeability in MASH specifically.
The study had several limitations worth noting: only 44 patients completed it (a relatively small number), the researchers didn’t carefully track what patients ate beyond general categories, and they only measured one marker of intestinal permeability (claudin-3). The study also didn’t look at whether probiotics might help other aspects of MASH, like inflammation or liver damage. Additionally, the probiotic dose used (1 × 10⁹ CFU) might not be the optimal amount—different doses could potentially work differently.
The Bottom Line
Based on this research, probiotics alone should not be considered a primary treatment for intestinal permeability in MASH patients. However, probiotics are generally safe and may have other benefits not measured in this study. If you have MASH, focus on proven treatments like weight loss, dietary changes, and working with your doctor on a comprehensive treatment plan. Probiotics might be a reasonable addition to your routine, but don’t rely on them as your main strategy. (Confidence level: Moderate—based on one study with a small sample size)
This research is most relevant to people diagnosed with MASH (metabolic dysfunction-associated steatohepatitis) who are considering probiotics as a treatment. It’s also important for healthcare providers treating MASH patients. People with other liver conditions or general digestive issues should not assume these results apply to them, as MASH is a specific disease. Healthy people taking probiotics for general wellness are not affected by this finding.
In this study, changes in intestinal permeability markers appeared within 24 weeks. However, this doesn’t mean you should expect dramatic health improvements in that timeframe. Real-world benefits like improved liver function, reduced inflammation, or weight loss typically take longer and depend on multiple factors including diet, exercise, and overall lifestyle.
Frequently Asked Questions
Do probiotics help with fatty liver disease?
Probiotics did not provide additional benefit beyond placebo in this 24-week study of 44 MASH patients. Both groups improved equally, suggesting dietary changes may matter more than probiotics for intestinal permeability in fatty liver disease.
Can probiotics reduce intestinal leakiness in people with MASH?
This 2026 trial found probiotics did not reduce intestinal leakiness (claudin-3 markers) more than placebo. Both groups showed similar 60%+ improvements, indicating other factors like reduced calorie intake likely drove the changes.
Should I take probiotics if I have metabolic dysfunction-associated steatohepatitis?
This research suggests probiotics alone won’t fix intestinal problems in MASH. Focus on proven strategies like dietary changes and weight loss with your doctor’s guidance. Probiotics are safe but shouldn’t be your primary treatment strategy.
What actually improved intestinal permeability in the MASH study?
Both probiotic and placebo groups reduced their calorie, carbohydrate, protein, and fat intake. Since both groups improved equally, dietary changes—not probiotics—likely drove the improvement in intestinal permeability markers.
Is this study proof that probiotics don’t work for any liver condition?
No. This study only tested probiotics for intestinal permeability in MASH specifically. Probiotics might help other aspects of liver disease or other conditions. Results from one study shouldn’t be applied to all liver diseases or health conditions.
Want to Apply This Research?
- Track daily probiotic intake (yes/no) alongside dietary changes (calories, protein, carbs, fats) to identify which factors correlate with how you feel. Since this study showed dietary changes may matter more than probiotics, monitoring both helps you understand what’s actually helping.
- If using the app to manage MASH, prioritize logging meals and tracking calorie/macronutrient intake rather than focusing heavily on probiotic supplements. Use the app to set realistic dietary goals (like reducing calories by 10-15%) and monitor progress, as dietary changes appeared to drive the improvements in this study.
- Set up weekly check-ins to review dietary patterns and any digestive symptoms. While this study didn’t show probiotics provided extra benefit, continue monitoring how you feel on probiotics if your doctor recommends them. Track energy levels, digestion, and any changes in how your clothes fit as longer-term indicators of improvement.
This research summary is for educational purposes only and should not replace professional medical advice. MASH is a serious medical condition requiring diagnosis and treatment by a qualified healthcare provider. Do not start, stop, or change any supplements or medications based on this article without consulting your doctor first. Individual results vary, and what works for research participants may not work for you. If you have MASH or suspect you do, seek evaluation from a hepatologist or gastroenterologist.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.