Scientists discovered that a specific type of helpful bacteria called Lactobacillus gasseri FN136, found naturally in breast milk, may help treat ulcerative colitis—a painful condition where the colon becomes inflamed and damaged. In laboratory and animal studies, this bacteria reduced inflammation, strengthened the gut barrier, and improved symptoms without needing to change the overall balance of gut bacteria. The bacteria works by producing special compounds that calm the immune system and protect the intestinal lining. While these results are promising, human studies are still needed to confirm whether this approach could help people with ulcerative colitis.

The Quick Take

  • What they studied: Whether a specific beneficial bacteria from breast milk could reduce inflammation and symptoms in ulcerative colitis, a chronic bowel disease
  • Who participated: The study used laboratory experiments and animal models (mice) with induced colitis. No human participants were involved in this research.
  • Key finding: The bacteria significantly reduced disease symptoms and inflammation markers in animal models. Importantly, it worked by producing healing compounds rather than by changing the overall gut bacteria population, which is different from how most probiotics are thought to work.
  • What it means for you: This research suggests a new way to treat ulcerative colitis that may be more targeted and effective than current probiotic approaches. However, this is early-stage research, and human studies are needed before this could become a treatment option. People with ulcerative colitis should continue following their doctor’s current treatment plan.

The Research Details

The researchers used a two-step approach to test this bacteria. First, they grew the bacteria in laboratory dishes to see what it produced and how it survived in harsh stomach conditions. They tested whether it could tolerate stomach acid and bile, and what beneficial compounds it made. Second, they gave the bacteria to mice with artificially induced colitis (similar to human ulcerative colitis) and measured how well it reduced inflammation and improved symptoms over time. They also analyzed the gut bacteria composition to understand how the bacteria worked.

Understanding exactly how probiotics work is crucial for developing better treatments. Most probiotics are thought to work by changing the types of bacteria in your gut, but this research suggests this particular bacteria works differently—by producing healing compounds that directly calm inflammation. This could lead to more effective and personalized treatments for people with ulcerative colitis.

This is laboratory and animal research, which is an important first step but doesn’t directly prove the bacteria would work in humans. The study was well-designed with multiple measurements of inflammation and immune function. However, animal studies don’t always translate to human results, so human clinical trials would be needed to confirm these findings before this could become a medical treatment.

What the Results Show

When mice received the bacteria daily, their ulcerative colitis symptoms improved significantly. The bacteria restored important amino acids in the blood that help reduce inflammation. The immune system’s regulatory cells (which calm inflammation) increased by 42%, and the colon showed much less damage and inflammation under the microscope. The mice also stopped losing weight and their colons didn’t shrink as much as untreated mice.

The bacteria produced special compounds called indole derivatives and amino acids that appear to be responsible for these benefits. These compounds directly communicate with the immune system and intestinal barrier to reduce inflammation. Importantly, blood markers of systemic inflammation—including proteins that indicate widespread inflammation—all decreased significantly.

Surprisingly, when researchers analyzed the overall composition of gut bacteria in treated mice, they found no major changes. This was unexpected and important because it showed the bacteria wasn’t working by replacing bad bacteria with good bacteria, but rather by producing healing compounds that work independently of the overall bacterial community.

Additional benefits included improved intestinal barrier function (measured by reduced leakage markers), decreased production of harmful inflammatory proteins, and reduced bacterial toxins in the bloodstream. The bacteria also showed strong ability to survive stomach acid and bile, meaning it could likely reach the colon intact if given to humans. In laboratory tests, the bacteria also showed antimicrobial activity, meaning it could fight harmful bacteria.

Most probiotic research focuses on how bacteria change the overall composition of gut microbiota. This study differs by showing that benefits can occur through a ‘postbiotic’ mechanism—meaning the healing compounds produced by the bacteria matter more than the bacteria itself. This aligns with emerging research suggesting that bacterial metabolites (products) may be more important than the bacteria themselves for health benefits. This represents a shift in how scientists think about probiotic therapy.

This research was conducted only in laboratory dishes and mice, not in humans. Animal studies don’t always produce the same results in people due to differences in immune systems, diet, and gut bacteria composition. The study didn’t test different doses to find the optimal amount. The specific type of colitis induced in mice (DSS-induced) may not perfectly match human ulcerative colitis. Additionally, the study was relatively short-term, so long-term effects are unknown. Human clinical trials would be necessary to determine if these benefits translate to people with ulcerative colitis.

The Bottom Line

This research is promising but preliminary. Current evidence suggests this bacteria may help treat ulcerative colitis, but human studies are needed before it can be recommended as a treatment. People with ulcerative colitis should continue working with their gastroenterologist on proven treatments. If this bacteria becomes available as a supplement, discuss it with your doctor before use, as it’s not yet an established medical treatment. Confidence level: Low to Moderate (early-stage research).

People with ulcerative colitis or those interested in new treatment approaches should follow this research. Researchers developing new probiotics and gastroenterologists treating inflammatory bowel disease should pay attention. People without ulcerative colitis don’t need to take action based on this single study. Those with severe or active ulcerative colitis should not delay proven treatments while waiting for this research to develop.

In the animal studies, benefits appeared within the study period (typically 1-2 weeks of treatment). If human trials eventually occur, it typically takes 5-10 years for a new probiotic treatment to move from animal studies to approved medical therapy. People should not expect this to become available as a treatment in the immediate future.

Want to Apply This Research?

  • Once human studies confirm effectiveness, users could track daily probiotic intake (if prescribed), symptom severity using a standardized scale (abdominal pain, bowel frequency, blood in stool), and energy levels. Measure changes weekly to assess response.
  • If this bacteria becomes available and recommended by a doctor, users could set daily reminders to take the supplement at the same time each day, ideally with food. Track adherence and note any changes in symptoms or side effects in the app’s symptom journal.
  • Long-term tracking should include monthly symptom assessments, quarterly check-ins with healthcare providers, and documentation of any flare-ups or improvements. Users should also track other factors that affect colitis (stress, diet, sleep) to understand the full picture of their condition management.

This research describes laboratory and animal studies only—not human clinical trials. These findings do not constitute medical advice or approval for human use. Ulcerative colitis is a serious medical condition requiring professional medical care. Anyone with ulcerative colitis should work with a qualified gastroenterologist and continue proven treatments. Do not stop or replace current medications based on this research. If you’re interested in probiotic supplements, discuss them with your healthcare provider first, as some may interact with medications or worsen symptoms in certain cases. This bacteria is not currently available as a medical treatment for humans.