Eating butter is not associated with an increased risk of death and disease, however eating margarine is associated with a greater risk of death and disease, new research has shown.
Research published in the British Medical Journal recently found that trans fats (margarine), but not saturated fats (butter, cows milk, meat, egg yolks), were linked with a greater risk of death and heart disease.
Higher trans fat intake associated with 20-30% increased risk, researchers found.
The study confirms previous suggestions that industrially produced trans fats might increase the risk of coronary heart disease.
It is recommended that saturated fats such as butter are limited to less than 10%, and trans fats to less than 1% of energy to reduce risk of heart disease and stroke.
Trans fats are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods, it says.
To help clarify these controversies, researchers in Canada analysed the results of observational studies assessing the association between saturated and/or trans fats and health outcomes in adults.
Study design and quality were taken into account to minimise bias, and the certainty of associations were assessed using a recognised scoring method, it says.
It was found that there was no clear association between higher intake of saturated fats like butter and all cause mortality, coronary heart disease (CHD), cardiovascular disease (CVD), ischemic stroke or type two diabetes, but could not, with confidence, rule out increased risk for CHD death.
The research also did not find evidence that diets higher in saturated fat reduce cardiovascular risk.
However, it found consumption of industrial trans fats was associated with a 34% increase in all cause mortality, a 28% increased risk of CHD mortality, and a 21% increase in the risk of CHD.
Inconsistencies in the included studies meant that the researchers could not confirm an association between trans fats and type two diabetes.
And researchers also found no clear association between trans fats and ischemic stroke.
The researchers point out that the certainty of associations between saturated fat and all outcomes was “very low,” which means that further research is very likely to have an important impact on our understanding of the association of saturated fats with disease.