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Randomized trial · measured other health measures

Fish oil trial in 18,353 US adults over 50: heart events about the same

Okereke and colleagues · JAMA · 2021

Original title: Effect of Long-term Supplementation With Marine Omega-3 Fatty Acids vs Placebo on Risk of Depression or Clinically Relevant Depressive Symptoms and on Change in Mood Scores: A Randomized Clinical Trial.

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

No difference

Depression risk was higher with fish oil (hazard ratio [HR], 1.13; 95% CI, 1.01-1.26). Major heart events as a side-effect check: 2.7% vs 2.9%. Gastrointestinal bleeding: 2.6% vs 2.7%.

The study at a glance

Type of study
Randomized trial
Who or what was studied
18,353 people · US adults aged 50 and older in the VITAL trial, checked for depression
What was tested
1 g a day of fish oil versus placebo, median 5.3 years
What it measured
Several kinds of outcomes
Daily amount
1 g a day
How long
276 weeks
Trial registration
NCT01696435, NCT01169259
Who has a stake
Company stake
One author got free product from Pronova BioPharma/BASF; another got free product from Nordic Naturals.
Journal
JAMA, 2021
Source
PubMed record 34932079. 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: 18,353 people.
  • ✓Long: about 5.3 years.
  • •Measured several kinds of outcomes.
  • –Company stake: One author got free product from Pronova BioPharma/BASF; another got free product from Nordic Naturals.
  • •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: heart attacks, strokes and heart deaths

    11

    7 benefit, 4 no difference

  2. Trials in people: other measures

    3

    1 benefit, 2 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 “Does fish oil prevent heart disease?”

Little or no effect in most trials.

Confidence: moderate. Based on 21 on-topic papers.

Read the full answer

Of the other 2 papers on the same step: 1 benefit, 1 no difference. This one found no difference.

Other papers on the same step

See all 21 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 3 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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