A new study by the US National Institute of Health based on prior Australian research has cast fresh doubts on whether margarine is healthier than butter. For decades, butter's more spreadable cousin has been considered a better option for weight-watchers trying to reduce fatty acids from their diet. However, according to the new report, margarine eaters are actually more likely to die from a heart attack than people who stick to butter.
Butter picture from Shutterstock
The research team based its findings on a recently unearthed Australian heart study from the 1960s and 70s, which monitored the dietary effects of two types of fats on 458 males between the ages of 30 and 59.
The test subjects, all of whom had suffered from a previous coronary event, were divided into two groups. One group was instructed to limit their intake of saturated animal fats in favour of omega 6 linoleic acid (a polyunsaturated vegetable fat commonly found in margarines). The other group was given no dietary advice at all. Over the course of the study, deaths caused by heart-related issues were significantly higher in the first group.
"In this cohort, substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease," the report stated. The study concludes that worldwide dietary guidelines need to rethink the "saturated fat bad, omega 6 good" dogma when it comes to processed foods and cooking ingredients.
However, before you toss out that tub of I Can't Believe It's Not Better, it's worth noting that the above findings are far from unanimously supported.
Bill Shrapnel, deputy chairman of the Sydney University Nutrition Research Foundation, has fired out at the US report which he claims is based on data from outmoded food manufacturing practices.
“The authors [of the US report] state that the [Australian] study assessed the effects of replacing saturated fat in the diet with omega 6 polyunsaturated fats, but it doesn't," Shrapnel explained in a public statement.
"The [original] study used Miracle margarine as a source of polyunsaturated fat. In the 1960s, when this study began, Miracle margarine contained approximately 15 per cent trans fatty acids, which have the worst effect on heart disease risk of any fat. The adverse effect of the intervention in this study was almost certainly due to the increase in trans fatty acids in the diet."
As Shrapnel goes on to explain, trans fatty acids were largely removed from Australian margarines in the mid-1990s when their dietary dangers were discovered.
In other words, while margarines of the past may well have been worse than butter, the brands on today's supermarket shelves are not quite as artery-clogging. The relatively small size of the study (just 63 total deaths) is also worth taking into consideration.
So is margarine better than butter? It seems we still won't have a definitive answer until a thorough study into the dietary effects of polyunsaturated fats is conducted.