(DAILY MAIL UK) – Guidelines urging people to avoid ‘unhealthy’ fat to stave off heart disease are wrong, according to a major study. After decades of advice on the harm done by saturated fat such as butter, scientists have found no evidence of a link with heart problems.
A ‘mega’ study which analyzed a huge amount of existing data also said so-called healthy polyunsaturated fats, such as sunflower oil, had no general effect on the risk of heart disease. In contrast, a dairy fat called margaric acid ‘significantly reduced’ risk, while two kinds of saturated fat found in palm oil and animal products had only a ‘weak link’ with heart disease.
Two types of omega-3 fatty acid found in oily fish – EPA and DHA – and the omega-6 fat arachidonic acid were linked to a lower risk of heart disease.
But omega-3 and omega-6 supplements appeared to have no benefit. This study comes in the wake of growing controversy over the relative importance of sugar and fat in the diet.
Fats have long been blamed for obesity and heart disease, but some scientists now say there is evidence that fat may have been unfairly demonized and sugar is really to blame.
Lead researcher Dr Rajiv Chowdhury, from Cambridge University, said:
‘These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines. Cardiovascular disease, in which the principal manifestation is coronary heart disease, remains the single leading cause of death and disability worldwide. In 2008, more than 17 million people died from a cardiovascular cause globally. With so many affected, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence. “
The team, whose results appear in the journal Annals of Internal Medicine, conducted a ‘meta-anaylsis’ of data from 72 studies involving 600,000 participants in 18 countries. The technique can reveal trends that may be masked in individual small studies but become obvious when the are amalgamated.
A key finding was the total saturated fat, whether measured in the diet or bloodstream, showed no association with heart disease. The study fails to ‘yield clearly supportive evidence for…guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of saturated fats.
Almost four decades ago advice began to emerge from scientific and medical bodies to cut back on saturated fats found in cream, butter and less lean meats. Last year, however, London cardiologist Dr. Aseem Malhotra told the British Medical Journal it was time to bust the myth of the role of saturated fat in heart disease, which was based on faulty interpretation of scientific studies. He said yesterday:
‘This huge and important study provides even more evidence that our focus purely on saturated fat as the number one dietary villain in causing heart disease has been misplaced when we should be focusing on food groups. Our over-consumption of processed food is what is driving much of the increasing burden of chronic disease currently plaguing the Western world. Poor diet is responsible for more disease than physical inactivity, alcohol and smoking combined. Furthermore, nutritional supplements have no proven benefit for the vast majority of people. It’s better for the body to gain essential nutrients from just eating real food.”
Professor Jeremy Pearson, associate medical director at the British Heart Foundation which co-funded the study, said:
‘This analysis of existing data suggests there isn’t enough evidence to say that a diet rich in polyunsaturated fats but low in saturated fats reduces the risk of cardiovascular disease. But large-scale clinical studies are needed, as these researchers recommend, before making a conclusive judgment.”
The industry-backed Health Supplements Information Service said that while the study showed only a modest protective effect of omega-3 fats, the trials involving omega-3 supplements nearly all involved non-healthy participants, which was likely to give misleading results.