Rapeseed oil, butter and cholesterol metabolism in men with metabolic syndrome
What it found
Swapping butter for cold-pressed rapeseed oil lowered blood cholesterol by 7.2% in men with metabolic syndrome.
The drop was not explained by changes in how the body makes or absorbs cholesterol.
What they found
Studies in people
Lower cholesterol levels
Blood cholesterol was 7.2% lower after the rapeseed oil period compared with the butter period. The daily dose of rapeseed oil provided 217 mg of plant sterols, while the butter provided only 1 mg.
Cholesterol production unchanged
Markers showing how much cholesterol the body made did not differ between the rapeseed oil and butter periods. A marker called PCSK9, which helps control cholesterol, also stayed the same.
Plant sterol markers rose
Two markers linked to plant sterols were 39% and 16% higher after the rapeseed oil period. The authors say this rise came from eating more plant sterols in the oil rather than a change in how the gut absorbs cholesterol.
What the authors conclude
- They found that replacing butter with cold-pressed rapeseed oil lowered bad cholesterol in men with metabolic syndrome.
- The authors say this drop could not be explained by changes in how the body makes or absorbs cholesterol, or by changes in PCSK9.
- They call for further research to work out exactly how rapeseed oil lowers cholesterol.
How it was done
Men with metabolic syndrome face a higher risk of heart problems. Earlier work showed that using rapeseed oil instead of butter lowered bad cholesterol, so the authors wanted to find out how.
Thirty-seven men with metabolic syndrome, aged 35 to 65, took part in a crossover trial. Each man added either 35 mL of cold-pressed rapeseed oil or 37.5 g of butter to his usual diet for 6 to 8 weeks. After an 8-week break, they switched to the other fat for another 6 to 8 weeks.
What it can’t tell you
- This trial included only men with metabolic syndrome, so the results may not apply to women or people without this condition.
- The participants knew which fat they were eating, which can sometimes influence behaviour during a study.
Who paid
- Conflicts
- Competing interests: None declared.
- Authors work at
- Kanta-Häme Central Hospital, Finland; University of Helsinki and Helsinki University Central Hospital, Finland; Mahasarakham University, Thailand
The paper
- Title
- Determining the mechanisms of dietary turnip rapeseed oil on cholesterol metabolism in men with metabolic syndrome
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Saarinen HJ, Sittiwet C, Simonen P, et al (2018). Determining the mechanisms of dietary turnip rapeseed oil on cholesterol metabolism in men with metabolic syndrome. Journal of investigative medicine. doi:10.1136/jim-2017-000495Free full textPubMed 28801309DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error