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Randomized trial · measured other health measures

12-week trial of probiotic plus vitamin D in 35 adults found mixed results

Laterza and colleagues · Nutrients · 2025

Original title: Multistrain Probiotics Plus Vitamin D Improve Gut Barrier Function and Gut Microbiota Composition in Irritable Bowel Syndrome Without Constipation: Results from a Double-Blind, Randomized, Placebo-Controlled Trial.

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What the study found

Mixed

Gut leak marker zonulin fell -19.01 vs placebo at week 16 (p = 0.0053). Stool frequency and consistency improved vs placebo. IBS symptom score (IBS-SSS) and quality of life did not differ.

The study at a glance

Type of study
Randomized trial
Who or what was studied
35 people · 35 adults with IBS without constipation
What was tested
OttaBac, a multi-strain probiotic plus vitamin D (cholecalciferol), vs placebo for 12 weeks, then followed to week 16
What it measured
Several kinds of outcomes
How long
12 weeks
Who has a stake
Company stake
Funded by Beingpharma; several authors advise or consult for Actial Farmaceutica and other drug and probiotic companies.
Journal
Nutrients, 2025
Source
PubMed record 40431448. This page is based on the abstract only.

How much this study counts

  • ✓Randomized: people were put into groups by chance, so the groups start out alike.
  • ✓Compared with a placebo, a dummy treatment.
  • –Small: 35 people. Small trials can miss real effects or find chance ones.
  • •Lasted 12 weeks.
  • •Measured several kinds of outcomes.
  • –Company stake: Funded by Beingpharma; several authors advise or consult for Actial Farmaceutica and other drug and probiotic companies.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

  1. Trials in people: gut symptoms such as bloating and IBS

    9

    5 benefit, 2 mixed, 2 no difference

  2. Trials in people: other measures

    10

    4 benefit, 2 mixed, 4 no difference

    ↑ This study is the ringed dot

  3. Trials in people: lab tests or safety

    0

    None among the papers we read.

  4. Population studies

    0

    None among the papers we read.

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Do probiotics improve gut health?”

Some strains may help some symptoms.

Confidence: low. Based on 28 on-topic papers.

Read the full answer

Of the other 9 papers on the same step: 4 benefit, 1 mixed, 4 no difference. This one found mixed.

Other papers on the same step

See all 28 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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