Meds & Biologics
If you have ulcerative colitis (UC), you have almost certainly been told to "take a probiotic." The advice is everywhere, from wellness blogs to well-meaning relatives, and it glosses over a simple reality: most commercial probiotics have no evidence behind them for UC. The research that does exist points to a small number of specific strains, tested at specific doses, in specific clinical contexts. Knowing which ones actually have data, and what the data says, is the difference between spending money on hope and making an informed decision about your gut health.
How the UC Microbiome Differs From a Healthy Gut
The gut microbiome of someone with UC looks meaningfully different from that of a healthy person. Research has consistently found reduced bacterial diversity in UC patients, with lower levels of Firmicutes (a major group of beneficial bacteria) and Bifidobacterium, alongside increases in sulfate-reducing bacteria that may contribute to inflammation.
One particularly important finding involves a bacterial family called Ruminococcaceae. These bacteria are present in virtually all healthy intestines, but significantly depleted in UC patients. This matters because Ruminococcaceae perform enzymatic operations that convert primary bile acids to secondary bile acids, a process tied to intestinal health. When these bacteria are missing, that metabolic pathway is disrupted.
The encouraging finding is that patients who achieve long-term remission show substantial recovery of gut microbial diversity, with compositions that begin to resemble a healthy microbiome. This suggests that the microbiome changes in UC are at least partially reversible, and that working toward remission has ripple effects on the broader gut ecosystem.
The Probiotic Strains That Actually Have UC Evidence
Out of the thousands of probiotic products on the market, only a handful of strains have been tested in UC clinical trials with meaningful results. Here are the ones with actual data.
E. coli Nissle 1917 is one of the best-studied probiotics in UC. A 12-month double-blind trial of 327 patients found that E. coli Nissle 1917 maintained remission as effectively as mesalazine, the standard maintenance drug. Relapse rates were 36.4% in the probiotic group and 33.9% in the mesalazine group. A subsequent meta-analysis confirmed these findings, showing remission rates of 61.6% with E. coli Nissle compared to 69.5% with mesalazine. This is maintenance therapy, meaning it helps keep UC in remission rather than treating active flares.
VSL#3 (now sold as Visbiome) is a high-potency multi-strain mixture that has been tested in several UC trials. In a randomized, double-blind study, patients with mild-to-moderate UC who took VSL#3 at 3.6 trillion colony-forming units (CFU) twice daily saw significantly higher improvement rates than placebo: 32.5% vs. 10% at six weeks. Another trial reported a 50% or greater reduction in disease activity in 63.1% of VSL#3 patients vs. 40.8% on placebo. VSL#3 also has strong evidence for preventing and treating pouchitis, the inflammation that can develop after J-pouch surgery.
Lactobacillus rhamnosus GG (LGG) has shown some promise in UC, with pilot data suggesting it can colonize the intestinal mucosa and reduce pro-inflammatory markers. Some clinical studies have found LGG effective for maintaining remission and delaying pouchitis onset, though the evidence is less robust than for E. coli Nissle or VSL#3.
The important takeaway: a generic "probiotic" supplement from the drugstore shelf, typically containing common Lactobacillus or Bifidobacterium strains at moderate doses, has not been shown to help with UC. The biological effect of any probiotic depends on the specific strain, the dose, and the severity of disease. A product label that says "Lactobacillus acidophilus" tells you almost nothing about whether it will affect your UC.
What About Prebiotics?
Prebiotics are fibers and compounds that feed beneficial gut bacteria rather than adding new bacteria directly. The logic behind using them in UC is sound: if your beneficial bacteria are depleted, give them fuel to grow back. The evidence, however, is limited.
A Cochrane systematic review found that prebiotics may not differ from placebo in preventing UC relapses. For adults in remission, prebiotics actually resulted in more side effects than placebo. The review noted that the evidence quality was low, with small study sizes and inconsistent reporting.
Some individual prebiotics have shown early-stage promise. Fructooligosaccharides (FOS) like 1-kestose improved clinical and endoscopic parameters in small studies. Galactooligosaccharides (B-GOS) improved stool consistency, though not other inflammatory markers. But none of these has enough evidence to warrant a general recommendation.
The practical concern for UC patients is timing. During an active flare, introducing prebiotic fibers can increase gas, bloating, and discomfort. Many gastroenterologists recommend waiting until remission is established before experimenting with prebiotics, and even then, starting with small amounts.
Fermented Foods: Kefir, Kombucha, Kimchi
Fermented foods occupy a middle ground between food and supplement. They contain live bacterial cultures, though usually in lower and less consistent concentrations than probiotic capsules. The appeal is obvious: they are whole foods, widely available, and feel more natural than pills.
The direct evidence in UC is mostly preclinical. A mouse study found that kombucha reduced inflammation and oxidative stress in a colitis model. Kefir reduced inflammatory markers and preserved intestinal lining in rats. Kimchi and the bacteria it contains reduced colitis symptoms in mice. These are animal studies, and the gap between mouse colons and human colons is significant.
For UC patients considering fermented foods, the practical concerns matter as much as the science. Kimchi and sauerkraut are high in sodium. Some commercial kombucha and kefir brands contain added sugar. Fermented foods can also be high in histamine, which may trigger gut symptoms in sensitive individuals. Starting with plain, unsweetened yogurt or kefir in small quantities is a lower-risk starting point than diving into kombucha or raw sauerkraut.
Bone Broth: What the Evidence Actually Shows
Bone broth has developed a devoted following among people with gut conditions, with claims ranging from "heals the intestinal lining" to "reduces inflammation." The actual research is thin.
One peer-reviewed study tested bone broth in a mouse model of UC and found that it reduced histological damage and decreased pro-inflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) while stimulating anti-inflammatory cytokines. The researchers confirmed that bone broth is rich in amino acids, with 54.56% being essential amino acids, which may support gut barrier function.
That is a single mouse study. There are no published human clinical trials testing bone broth for UC. Bone broth is unlikely to cause harm and provides protein and minerals. But the specific claim that it "heals" the gut lining in UC patients is not supported by human evidence. Treating it as a nutritious food rather than a therapeutic intervention is a more accurate framing.
Making Decisions About Microbiome Support
The gap between microbiome science and actionable advice for UC patients is real. Researchers understand that UC involves dysbiosis, reduced diversity, and specific bacterial deficiencies. Translating that into reliable treatments is an ongoing process, not a finished one.
If you are considering a probiotic, the evidence favors asking your gastroenterologist specifically about E. coli Nissle 1917 for maintenance therapy or VSL#3/Visbiome for mild-to-moderate active disease. These are the strains with clinical trial data in UC. A safety note: during severe active disease with mucosal disruption, even well-studied probiotics should be used cautiously and under medical supervision.
For prebiotics, fermented foods, and bone broth, the honest assessment is that the evidence is preliminary. None of these has enough clinical data to recommend as a UC treatment, but none is likely to be harmful when introduced carefully during remission.
Trying a new probiotic or fermented food? Track it alongside your symptoms in Aidy to see if it's making a real difference over weeks, not just days.