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Systematic review

Review of 249 trials: probiotic effects vary by strain; strong evidence for antibiotic diarrhea

Sniffen and colleagues · PloS one · 2018

Original title: Choosing an appropriate probiotic product for your patient: An evidence-based practical guide.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Points to benefit

Effects depend on the strain and the condition. Several products had strong evidence for preventing antibiotic diarrhea. Two types had strong evidence for IBS. 15 of 22 types (68%) had strong-moderate evidence for at least one disease.

The study at a glance

Type of study
Systematic review
Who or what was studied
249 studies · patients with gut conditions such as antibiotic diarrhea, child diarrhea, IBS and bowel disease
What was tested
22 types of probiotic products, graded by the strength of trial evidence (249 trials)
What it measured
The question itself: gut symptoms such as bloating, pain and irregular bowels
Trial registration
PROSPERO CRD42018103979
Who has a stake
Company stake
Funded by Bio-K+, which makes a probiotic; several authors are on its advisory board or are paid lecturers.
Journal
PloS one, 2018
Source
PubMed record 30586435. This page is based on the abstract only.

How much this study counts

  • •Sums up 249 studies found with a set search method, without pooling the numbers.
  • ✓Measured the question itself: gut symptoms such as bloating, pain and irregular bowels.
  • –Company stake: Funded by Bio-K+, which makes a probiotic; several authors are on its advisory board or are paid lecturers.
  • •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

This paper is not on the ladder. It is a systematic review, and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ 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

  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
  • Quoted in “What we found”: Effects are strain-specific: one B. longum strain eased constipation while a version lacking the abfA genes did not, so results for one product do not carry over.
  • Part of the finding “Dose and strain change the result”.

Other reviews on this question

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 reviewer corrected 1 field after reading the abstract. 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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