Saturated fat does not increase the risk of a heart attack by clogging up arteries, three cardiologists have said in a challenge to medical thinking, sparking a furious backlash.
In an editorial published in the British Journal of Sports Medicine the cardiologists also write that relying on foodstuffs marketed as “low fat” or “proved to lower cholesterol” to avoid heart disease is “misguided”.
A key previous research study, they say, “showed no association between saturated fat consumption and all-cause mortality, coronary heart disease, CHD mortality, ischaemic stroke or type-2 diabetes in healthy adults”. Instead they say that a Mediterranean-style diet and 22 minutes of walking a day are the best ways to prevent heart problems.
The paper co-authored by Pascal Meier, a cardiologist at University College London and editor of the journal BMJ Open Heart; Rita Redberg, the editor of the American journal JAMA Internal Medicine; and Aseem Malhotra, a cardiologist at the NHS’s Lister hospital in Stevenage, has triggered furious criticism from a range of experts in cardiology and evidence-based medicine. Some said the views were not based on reliable evidence and would mislead consumers and further confuse the public over which foods they should eat and which they should avoid.
They also dismiss the potential for a smaller intake of saturated fats to help prevent heart disease. “There is no benefit from reduced fat, including saturated fat, on myocardial infarction [heart attacks], cardiovascular or all-cause mortality,” they say.
Instead of adopting a low-fat diet, people seeking to cut their risk of heart problems should instead follow “an energy-unrestricted Mediterranean diet (41%) fat supplemented with at least four tablespoons of extra virgin olive oil or a handful of nuts”.
But critics responded by accusing the co-authors of naiveté, ignoring evidence which contradicts their theories and simplifying a hugely complex issue.
Dr Amitava Banrejee, a senior clinical lecturer in clinical data science and honorary consultant cardiologist at UCL, said: “Unfortunately the authors have reported evidence simplistically and selectively. They failed to cite a rigorous Cochrane systematic review which concluded that cutting down dietary saturated fat was associated with a 17% reduction in cardiovascular events, including CHD, on the basis of 15 randomised trials.”
Dr Gavin Sandercock, director of research at Essex University, rejected the trio’s claims about the benefit of “replacing refined carbohydrates with healthy high fat foods” as not true and not based on any existing evidence. “We must continue to research the complex links between fat, cholesterol and heart disease but we must not replace one myth with another”, Sandercock said.
Christine Williams, professor of human nutrition at Reading University, said the cardiologists’ dietary advice was impractical, especially for poorer people. “The nature of their public health advice appears to be one of ‘let them eat nuts and olive oil’ with no consideration of how this might be successfully achieved in the UK general population and in people of different ages, socioeconomic backgrounds or dietary preferences,” she said.
However, some experts did back the authors. Dr Mary Hannon-Fletcher, head of the school of health sciences at Ulster University, hailed their views as “the best dietary and exercise advice I have read in recent years. Walking 22 minutes a day and eating real food. This is an excellent public health message.
“The modern idea of a healthy diet where we eat low-fat and low-calorie foods is simply not a healthy option. All of these foods have been so altered they are anything but healthy. So eating real foods in moderation and exercising daily is the answer to keeping fit and healthy; it’s just too simple a message for the public to take on board,” she said.
Gaynor Bussell, a dietitician and member of the British Dietetic Association, also offered the authors qualified support. “Many of us now feel that a predominantly Med-style diet can be healthy with slightly more fats and fewer carbs, provided the fats are ‘good’ – such as in olive oil, nuts or avocados,” she said.
However, saturated fats should comprise no more than 11% of anyone’s food intake, she said – far less than the 41% fat level backed by the co-authors.
While carbohydrates should still be part of every meal, people should routinely consume high fibre or wholegrain versions, Bussell said.
Williams also accused the BJSM of publishing opinions seeking to portray saturated fats as “innocent” in the causation of heart disease in order to generate headlines. “Some would argue the journals have a very credible business model based on attracting controversy in an area of great importance to public health where clarity, not confusion, is required,” she said.