Replacing Butter With Vegetable Oil May Not be as Heart Healthy as Previously Thought
A recent re-examination of old data has found that replacing butter with vegetable oil does not reduce the risk of heart disease and overall mortality. In fact, the study found that vegetable oils rich in linoleic acid may actually be worse for heart health than butter. Linoleic-rich oils include safflower, soybean, sunflower, and cottonseed oil.
For this study, researchers looked at previously unpublished data from a trial that was conducted in Minnesota nearly 50 years ago. They also performed a broad analysis of published data on similar trials that examined the effects of butter and vegetable oil on heart health.
The Minnesota trial was called the Minnesota Coronary Experiment and it took place from 1986 to 1973, with a total of 9,423 participants. Results from the study were published in 1989, at which point the original researchers reported that using corn oil instead of butter and other saturated fats lowered cholesterol levels but did not have an effect on heart attacks, death from heart attack, or overall mortality.
Researchers from the National Institutes of Health re-examined the data and realized that some of the analyses the original researchers had planned on doing were missing from the report. They enlisted the help of the son of the deceased original researcher in order to recover much of the raw data from the original study. They also found trial data and analyses conducted by a student of one of the original researchers.
Using that data, the researchers were able to perform the missing analyses. They confirmed that the linoleic-rich vegetable oils were associated with a reduction in cholesterol. However, women and people older than 65 in the vegetable oil group were 15% more likely to die during the trial when compared with the controls.
The researchers caution that they were not able to find the individual patient data and therefore were not able to determine whether or not these results were statistically significant. They also pointed out that other analyses were based on partial recovery of patient data. However, their conclusions do concur with other recent studies that have found no association between replacing butter with vegetable oils and lower risk of heart attack, death from heart attack, or overall mortality.
Researchers from the University of North Carolina School of Medicine and the National Institutes of Health conducted the study. It was published on April 12, 2016, in BMJ.
While this study suggests that saturated fats may not be as bad for us as previously thought, it’s not recommended that people greatly increase their intake of saturated fats, as they don’t seem to have any discernible health benefit. A balanced diet of fats, proteins, fruits, vegetables, and grains in combination with regular exercise is the best lifestyle choice for better heart health.