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Population study: followed a group

Study of 135,335 adults: polyunsaturated fat linked to lower death risk, not heart attacks

Dehghan and colleagues · Lancet (London, England) · 2017

Original title: Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study.

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What the study found

Mixed

Highest polyunsaturated fat intake went with lower risk of death from any cause (HR 0·80 [0·71-0·89]). Fat types were not linked to heart attack or heart deaths.

The study at a glance

Type of study
Population study: followed a group
Who or what was studied
135,335 people · adults aged 35 to 70 in 18 countries, followed a median 7.4 years
What was tested
Highest vs lowest fifth of polyunsaturated fat intake (and other fats and carbs), from food questionnaires
What it measured
The question itself: heart disease and inflammation
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
Lancet (London, England), 2017
Source
PubMed record 28864332. This page is based on the abstract only.

How much this study counts

  • –Shows a link, not a cause: people chose their own habits, and other differences between them may explain the result.
  • ✓Followed people over time, so habits were recorded before the outcome happened.
  • ✓Large: 135,335 people.
  • ✓Measured the question itself: heart disease and inflammation.
  • •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: heart disease

    1

    1 harm

  2. Trials in people: other measures

    0

    None among the papers we read.

  3. Trials in people: lab tests or safety

    4

    1 benefit, 3 no difference

  4. Population studies

    2

    2 mixed

    ↑ This study is the ringed dot

  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 “Are seed oils bad for your heart?”

Not clearly; the evidence conflicts.

Confidence: very low. Based on 13 on-topic papers.

Read the full answer

Few other papers sit on the same step, so there is little to compare it with.

  • Quoted in “What we found”: Among 135 335 adults in 18 countries, those eating the most polyunsaturated fat had fewer deaths overall (HR 0·80), but no link to heart attacks or heart deaths.
  • Part of the finding “Reviews of population studies lean toward benefit”.
  • Marked as a key paper in the research timeline: PURE: 135 335 adults followed in 18 countries.
  • Open item for a person: Hooper 2020 (Cochrane saturated fat) added as relevant and Dehghan 2017 (PURE) kept, though both cover all polyunsaturated fat, not seed oils; confirm inclusion.

Other papers on the same step

See all 13 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
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