Swapping the butter for margarine 'may be 
 
 bad for your health'. U.S. scientists claim polyunsaturated fat 'doubles heart risk' 
 
 
 
 Men who eat margarine over butter could be more prone to heart disease 
 
 Findings come from new analysis of study done four decades ago 
 
 But some researchers have blasted the research as 'underpowered' 
 
 
 
 Eating margarine instead of butter may not be good for you after all, scientists have warned. 
 
 For the past 50 years, we have been advised to reduce our intake of saturated animal fats, and eat more of the polyunsaturated vegetable fats found in margarine. 
 
 
 
 But now scientists in the US claim to have turned that conventional wisdom on its head, with a new analysis of a study carried out between 1966 and 1973. Some of the data had been missing for decades. 
 
 
 
 The study, conducted in Sydney, followed 458 men aged 30 to 59 who had recently had a heart attack or suffered from angina. 
 
 
 
 Spreading doubt: Butter (left) may not be more harmful to health than margarine (right), according to U.S. scientists 
 
 Half were advised to cut their animal fat consumption and replace it with safflower oil – similar to sunflower oil – and safflower oil margarine. 
 
 
 
 The results, published in the British Medical Journal, showed that those who ate more of these products were almost twice as likely to die from all causes, including heart disease. 
 
 They chose the Sydney study because it was the only randomised controlled study to look at the impact of increasing consumption of omega 6 polyunsaturated fatty acid. 
 
 
 
 Most studies of dietary interventions have involved multiple changes, but the Sydney study looked solely at omega 6. 
 
 
 
 Omega 6, the most prevalent polyunsaturated fat in most Western diets, is also known as linoleic acid. 
 
 Diners who prefer the taste of butter to margarine but don't want their health to suffer will rejoice at the findings 
 
 It is found in large quantities in vegetable oils such as corn, sunflower, safflower and soybean and in margarines made from these oils. 
 
 
 
 Once in the body, it is converted into a chemical called arachidonic acid which can trigger the release of other chemicals leading to inflammation, a leading cause of a host of chronic diseases – including heart disease. 
 
 
 
 The researchers, from the National Institutes of Health in the U.S., say their findings could have ‘important implications for worldwide dietary recommendations’. 
 
 
 
 But other scientists have criticised the results, saying they did not provide enough evidence to suggest people should change their diets. 
 
 
 
 Professor Tom Sanders, of King’s College London, said the study was ‘enormously underpowered’, of ‘little relevance to diets today’ and its findings had been refuted by recent better studies. 
 
 
 
 Professor Brian Ratcliffe, of Aberdeen University, said: ‘This paper does not provide evidence for changes to the current recommendations for a healthy diet.’ 
 
 And Victoria Taylor, senior dietician at the British Heart Foundation, said: ‘Our understanding of the effect of different fats on our heart develops all the time as new research into this complex issue is published. 
 
 
 
 ‘Replacing saturated fats with unsaturated alternatives is a well-known recommendation for your heart, which is based on many large and in-depth studies. 
 
 
 
 ‘However, this research highlights the need for us to further understand how different unsaturated fats affect our risk of heart disease. 
 
 
 
 ‘Whichever fats you use it is important to be sparing with them.’ 
 
 
 
 Vegetable oils and margarine are supposed to help lower cholesterol and blood pressure and increase weight loss and improve overall health. 
 
 

 In an exceedingly strange turn of events, data from a clinical trial dating from the 1960s, long thought to be lost, has now been resurrected and may contribute important new information to the very contemporary controversy over recommendations about dietary fat composition. 
 
 The American Heart Association has long urged people to increase their consumption of polyunsaturated fatty acids (PUFAs), including omega 6 PUFAs, and reduce their consumption of saturated fatty acids. The recommendations are based on the simple observation that PUFAs lower total and LDL cholesterol while SFAs have the opposite effect. However, the cardiovascular effects of substituting PUFAs for SFAs have never been tested in randomized, well-controlled clinical trials, and a growing proportion of experts now suspect that simple changes in total cholesterol and LDL cholesterol may not tell the whole story. 
 
 One trial that actually tested the hypothesis was the Sydney Diet Heart Study, which ran from 1966 through 1973. In the trial, 458 men with coronary disease were randomized to a diet rich in linoleic acid (the predominant omega 6 PUFA in most diets) or their usual diet. Although total cholesterol was reduced by 13% in the treatment group during the study, all-cause mortality was higher in the linoleic acid group than in the control group. However, in the original publications, and consistent with the practice at the time, deaths from cardiovascular (CVD) and coronary heart disease (CHD) deaths were not published. 
 
 Now, in a new paper published in BMJ, Christopher Ramsden and colleagues report that they were able to recover and analyze data from the original magnetic tape of the Sydney Diet Heart Study. The new mortality findings are consistent: 
 
 All cause: 17.6% in the linoleic group versus 11.8% in the control group, HR 1.62, CI 1.00-2.64) 
 
 CV disease: 17.2% versus 11%, HR 1.70, CI 1.03-2.80 
 
 CHD: 16.3% versus 10.1%, HR 1.74, CI 1.04-2.92 
 
 The investigators then used this data to perform an updated meta-analysis and found similar but nonsignificant trends for overall mortality and for cardiovascular disease and coronary heart disease mortality. They concluded that their findings "could have important implications for worldwide dietary advice to substitute" polyunsaturated fatty acids for saturated fatty acids. 
 
 In an accompanying editorial, Philip Calder agrees:
– Eating margarine in an effort to safeguard your heart? In what Forbes terms "an exceedingly strange turn of events," it turns out the fake stuff may be worse for your heart than the real stuff. Researchers were able to access previously unpublished mortality data from a nearly five-decades-old study of 458 heart disease patients. The data revealed that while the group that switched from saturated fatty acids (ie, butter) to polyunsaturated fatty acids (in this case, safflower oil and safflower margarine) did indeed see a 13% drop in cholesterol, they were more likely to die from cardiovascular or coronary heart disease. As the Daily Mail reports, this is the only "randomized controlled study" to look at the increased consumption of omega 6. Also known as linoleic acid, it's found in margarine made from corn, sunflower, safflower, and soybean oil and happens to be the most common PUFA found in most Western diets. The body converts it to arachidonic acid, which can ultimately spur inflammation ... which just so happens to be a leading cause of heart disease. But the Mail spoke with a number of scientists who pooh-poohed the study, with one calling it "enormously underpowered."