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Randomized trial · measured the question itself

4-week trial in 362 women: only the middle probiotic dose beat placebo

Whorwell and colleagues · The American journal of gastroenterology · 2006

Original title: Efficacy of an encapsulated probiotic Bifidobacterium infantis 35624 in women with irritable bowel syndrome.

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What the study found

Mixed

Only the 1 x 10(8) cfu dose beat placebo for belly pain, bloating and bowel symptoms; global relief exceeded placebo by more than 20% (p < 0.02). The 1 x 10(6) and 1 x 10(10) doses did not differ from placebo.

The study at a glance

Type of study
Randomized trial
Who or what was studied
362 people · 362 women with IBS seen in primary care
What was tested
Bifidobacterium infantis 35624 at 1 x 10(6), 1 x 10(8) or 1 x 10(10) cfu vs placebo for 4 weeks
What it measured
The question itself: gut symptoms such as bloating, pain and irregular bowels
How long
4 weeks
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
The American journal of gastroenterology, 2006
Source
PubMed record 16863564. 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.
  • ✓Large: 362 people.
  • –Short: 4 weeks. Longer-term effects are unknown.
  • ✓Measured the question itself: gut symptoms such as bloating, pain and irregular bowels.
  • •The PubMed record has no conflict-of-interest statement.
  • •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

    ↑ This study is the ringed dot

  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

Of the other 8 papers on the same step: 5 benefit, 1 mixed, 2 no difference. This one found mixed. It differs from most of them.

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 reviewer corrected 2 fields 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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