Margarine and butter fats: blood markers in a 4-week trial
What it found
In a 4-week trial in 42 healthy adults, eating margarine or butter changed many fats and other molecules in the blood, mostly separating butter from margarine.
Gene activity in blood cells did not differ between the diets.
What they found
Studies in people
Blood fats reflect diet
After 4 weeks, 18 fatty acids and 242 other blood features differed between the diet groups. These mostly separated the butter group from the two margarine groups.
Trans fats in blood
The main trans fat in margarine (elaidic acid) and the main one in butter (trans vaccenic acid) showed up at higher levels in the blood of people who ate those fats. The margarine without trans fats did not raise either.
Cholesterol changes
Total cholesterol and LDL cholesterol rose slightly more in the butter group than in the margarine groups. HDL cholesterol and triglycerides did not differ significantly between groups.
Gene activity unchanged
Gene expression in blood cells was not significantly different between the diets after accounting for multiple testing.
Butter markers
Several molecules in the blood increased only after butter, including phytanic acid and 4-isopropylbenzoic acid. These may be markers of dairy fat intake.
Margarine markers
Retinol (a form of vitamin A) decreased after butter relative to margarine, possibly because margarines are often fortified with it.
What the authors conclude
“The untargeted serum metabolome differentiates margarine from butter intake although the identification of the discriminating features remains a bottleneck.”
Also in their conclusions
- They conclude that the different types and amounts of trans fats in margarine and butter lead to distinct changes in blood trans fats after 4 weeks.
- They note that the associations between trans fats and clinical markers were not specific to trans fats but related to the overall fat composition.
- They suggest that blood markers can distinguish butter from margarine intake, though they did not find clear markers that separated the two margarines.
How it was done
The authors wanted to find molecular signatures in blood that could tell apart different dietary fats, since the health effects of trans fats from industrial and ruminant sources are still debated.
42 healthy men and women aged 45 to 69 were randomly assigned to eat margarine without trans fats, margarine with industrial trans fats, or butter with ruminant trans fats for 4 weeks. Blood was collected before and after to measure fatty acids, other molecules, and gene activity.
What it can’t tell you
- This was a 4-week study in healthy adults, so it cannot show what would happen over a longer period or in people with health conditions.
- The study measured molecular changes in blood, not whether these changes affect long-term health outcomes like heart disease.
Who paid
- Conflicts
- The authors declare that they have no competing interests.
- Authors work at
- University Clinic for Cardiology, Switzerland; University of Zurich, Switzerland; University of Bern, Switzerland
The paper
- Title
- Molecular effects of the consumption of margarine and butter varying in trans fat composition: a parallel human intervention study
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Guggisberg D, Burton-Pimentel KJ, Walther B, et al (2022). Molecular effects of the consumption of margarine and butter varying in trans fat composition: a parallel human intervention study. Lipids in health and disease. doi:10.1186/s12944-022-01675-1Free full textPubMed 35982449DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error