When the Scan Looks Fine and the Pain Is Still There
Plenty of people leave a colonoscopy with a result that sounds like good news and does not feel like it. You have diverticulosis, meaning small pouches in the wall of the colon. There is no inflammation, no bleeding, and nothing that requires surgery. The cramping keeps coming back anyway. The mismatch between what the camera sees and what a person feels has a name, symptomatic uncomplicated diverticular disease, or SUDD, and a study published in Scientific Reports in August offers a partial explanation for it.
What the Japanese sequencing study found
Ishibashi and colleagues enrolled patients at five Japanese centers who had come to outpatient clinics with stubborn abdominal pain [1]. By sequencing fecal samples, they compared three groups: 29 people meeting the criteria for SUDD, 35 who had diverticulosis without meeting those criteria, and 68 asymptomatic controls.
Two findings separated the groups. Overall microbial diversity was lower in everyone with diverticulosis, symptomatic or not, than in healthy controls. Diversity by itself therefore does not explain who ends up in pain.
Specific organisms did track with symptoms. The Ruminococcus gnavus group was more abundant in the SUDD group than in either comparison group, whereas Coprococcus was less abundant. Butyrate-producing bacteria as a whole category were reduced in SUDD. Butyrate is the short-chain fatty acid that colon cells use as their main fuel, so a shortfall there plausibly leaves the lining less able to maintain itself.
The authors are careful about the limits of this study, and so am I. Their metabolic findings came from PICRUSt2, software that predicts bacterial function from gene sequences rather than measuring the chemistry directly. Butyrate itself was never measured in stool or tissue. They call the work exploratory and observational and state that the associations need confirmation through direct functional and metabolomic measurement. The sample was small, and everyone came through Japanese specialist clinics.
One correction to the coverage. Some reporting on this study said Bifidobacterium was significantly higher in the SUDD group. That claim does not appear in the published abstract, so it is not repeated here.
Have other research groups found the same pattern?
Broadly yes, with a caveat that keeps recurring across microbiome science: the effects are measurable and they are small.
An Italian group profiled 72 people with SUDD against 30 with asymptomatic diverticulosis and likewise found no difference in overall diversity between those two groups [2]. What they did find was that the makeup of the bacterial community differed according to how severe the abdominal pain was. Milder pain went with more health-associated organisms, more severe pain with a less favorable set. Two research teams on opposite sides of the world reached a similar conclusion: the bacterial community around the pouches seems to be more closely tied to symptoms than the pouches themselves.
There is a limit to this, though. A US study sequenced gut samples from 684 adults having screening colonoscopies, 284 of whom had diverticulosis [3]. Microbiome composition accounted for 1.9% of the variation in who had it. That is measurable, and nowhere close to a full explanation. If anyone tells you your gut bacteria explain your diverticular disease, they are well out ahead of the evidence.
Why normal imaging doesn't mean nothing is wrong
The finding that stays with me most has nothing to do with a specific organism. People whose imaging looks unremarkable, who get told there is nothing much wrong, have measurable differences in their gut ecology. That is validating in a concrete way. The pain was never imaginary. The tests used to evaluate it were examining structure, while the problem was in function.
Root-cause thinking here means asking what depleted the butyrate producers to begin with. Common causes include long or repeated antibiotic courses, years of low fiber intake, prior infections, and chronic stress altering motility. Those histories turn up constantly in an intake, and they are the part that can still be worked on. A pouch in the colon wall is permanent. The community living in that colon is not.
Diet appears to be one factor you can change. The same Italian group examined eating patterns in 47 people with SUDD and found that those following a Mediterranean or predominantly plant-based diet carried greater microbial diversity, with more fiber degraders and short-chain fatty acid producers, than those eating an omnivorous pattern [4]. That association weakened as disease severity rose, so diet appears to help, within limits. At Yggdrasil Naturopathic the order of operations is deliberate: motility and mucosal support come before any attempt at probiotic rebuilding [5], since seeding new organisms into a gut that is not moving well tends not to work well.
What people with diverticular disease can do
The nuts-and-seeds rule can go. For decades people with diverticular disease were told to avoid nuts, corn, popcorn, and seeds. A prospective study that followed 47,228 men over 18 years found no increase in diverticulitis or diverticular bleeding associated with any of them, and men eating nuts or popcorn at least twice a week had somewhat lower rates of diverticulitis [6]. Only men were included, so this is not the last word, though it is considerably more evidence than anyone had when the original advice was given.
Fiber is the better target, and it is best added slowly. Plant-forward eating patterns were the ones associated with healthier bacterial profiles in the diet study, and no single supplement reproduces what a varied diet does.
If pain is your main symptom and you have been told the diverticulosis is incidental, ask about the other possible contributors anyway. Motility, previous antibiotic exposure, and overlapping conditions such as irritable bowel syndrome all belong in that conversation.
Sudden severe pain, fever, or rectal bleeding is a different situation altogether. That needs same-day medical attention rather than a change in diet.
References
Primary research verified via PubMed and CrossRef.
Ishibashi F, Jono T, Kasai Y, et al. Significant alteration of gut microbiota in patients with symptomatic uncomplicated diverticular disease. Sci Rep. Published online August 24, 2026. https://doi.org/10.1038/s41598-026-67357-5. Not yet PubMed-indexed at time of writing; authorship, abstract, and publication date verified through CrossRef.
Tursi A, Turroni S, De Bastiani R, et al. Gut microbiota in symptomatic uncomplicated diverticular disease stratifies by severity of abdominal pain. Eur J Gastroenterol Hepatol. 2025;37(2):147-153. PMID 39514266. https://doi.org/10.1097/MEG.0000000000002884
Hua X, McGoldrick J, Nakrour N, et al. Gut microbiome structure and function in asymptomatic diverticulosis. Genome Med. 2024;16(1):105. PMID 39180058. https://doi.org/10.1186/s13073-024-01374-9
Tursi A, Procaccianti G, D'Amico F, et al. Impact of diet on gut microbiota in diverticular disease of the colon: an exploratory retrospective study. Microorganisms. 2025;13(11):2428. PMID 41304114. https://doi.org/10.3390/microorganisms13112428
Yggdrasil Naturopathic internal clinical protocols: Gut Healing — Part 1 (Mucosal Repair, gut_healing_part1) and Gut Healing — Part 2 (Probiotic Remodeling, gut_healing_part2). Both approved, last updated 2026-02-26.
Strate LL, Liu YL, Syngal S, Aldoori WH, Giovannucci EL. Nut, corn, and popcorn consumption and the incidence of diverticular disease. JAMA. 2008;300(8):907-914. PMID 18728264. https://doi.org/10.1001/jama.300.8.907
Digest source article: News-Medical. "Scientists found a distinct gut microbiome pattern in people with symptomatic diverticular disease." August 25, 2026. https://www.news-medical.net/news/20260825/Scientists-found-a-distinct-gut-microbiome-pattern-in-people-with-symptomatic-diverticular-disease.aspx
A note before you go
This article is educational and is not medical advice. Diverticular disease ranges from mild to severe, and where you are in that range changes what makes sense for you, which is a conversation for you and your own provider rather than an article. If you are dealing with pain that has been waved off as incidental, I hope this gives you something specific to bring to that appointment. You are allowed to keep asking.
If this resonates with what you're experiencing and you'd like to explore a naturopathic approach, book a consultation with our clinic.
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