LONDON: A dollop of ghee or butter in your diet does not cause as much harm to your heart as it was believed till now.
Researchers from the University of Cambridge and the British Heart Foundation have found there is actually no evidence that confirms changing the type of fat you eat from "bad" saturated to "healthier" polyunsaturated cuts heart risk.
The researchers analysed data from 72 unique studies with over 600,000 participants from 18 nations and found total saturated fatty acid, whether measured in the diet or in the bloodstream as a biomarker, was not associated with coronary disease risk in the observational studies.
Similarly, when analysing the studies that involved assessments of the consumption of total monounsaturated fatty acids, long-chain omega-3 and omega-6 polyunsaturated fatty acids, there were no significant associations between consumption and cardiovascular risk.
Saturated fat is the kind of fat found in butter, biscuits, red meat, sausages and bacon and cheese and cream. There has been a big drive to get more people eating unsaturated fats, such as olive and sunflower oils, and other non-animal fats instead.
But the latest study raises questions about the current guidelines that generally restrict the consumption of saturated fats and encourage consumption of polyunsaturated fats to prevent heart disease.
"These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines," said Dr Rajiv Chowdhury, lead author of the research at the University of Cambridge. "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 by this illness, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence."
The research collaboration led by the University of Cambridge analysed existing cohort studies and randomised trials on coronary risk and fatty acid intake. They showed that current evidence does not support guidelines which restrict the consumption of saturated fats in order to prevent heart disease.
The researchers also found insufficient support for guidelines which advocate the high consumption of polyunsaturated fats (such as omega 3 and omega 6) to reduce the risk of coronary disease.
Furthermore, when specific fatty acid subtypes (such as different types of omega 3) were examined, the effects of the fatty acids on cardiovascular risk varied even within the same broad family — questioning the existing dietary guidelines that focus principally on the total amount of fat from saturated or unsaturated rather than the food sources of the fatty acid subtypes.
Within saturated fatty acid, the researchers found weak positive associations between circulating palmitic and stearic acids (found largely in palm oil and animal fats, respectively) and cardiovascular disease, whereas circulating margaric acid (a dairy fat) significantly reduced the risk of cardiovascular disease.
Additionally, when the authors investigated the effects of omega-3 and omega-6 fatty acid supplementations on reducing coronary disease in the randomised controlled trials, they did not find any significant effects — indicating a lack of benefit from these nutrients.
"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," said Professor Jeremy Pearson from the British Heart Foundation, which helped fund the study. "But large-scale clinical studies are needed, as these researchers recommend, before making a conclusive judgement. Alongside taking any necessary medication, the best way to stay heart healthy is to stop smoking, stay active and ensure our whole diet is healthy — and this means considering not only the fats in our diet but also our intake of salt, sugar and fruit and vegetables."