Reducing saturated fat intake very slightly can lower your risk of developing heart disease, according to a study at Harvard University (but see our expert analysis below).
This means cutting down on foods such as cheese, milk, butter and meat and replacing them with with polyunsaturated fats, whole grain carbohydrates and plant-based proteins.
The researchers found that a one per cent reduction, when replaced with more healthy food, could cut heart disease risk by up to eight per cent.
They also found that a five per cent higher intake was associated with a 25 per cent increased risk of coronary heart disease over a period of 28 years.
The study, published in the British Medical Journal, involved over 115,000 US men and women examined between 1984 and 2010, all of whom were free of major long-term illnesses at the beginning of the study. They were quizzed about their diets and heart health every four years.
Qu Sun, an assistant professor who worked on the study, said: ‘Higher dietary intakes of major saturated fatty acids are associated with an increased risk of coronary heart disease.
‘Dietary recommendations should remain on replacing total saturated fat with unsaturated fats or whole-grain carbohydrate, as an effective approach towards preventing coronary heart disease.’
This paper was an analysis of two large prospective cohort papers, with healthcare professionals being the study subjects (exceeding 110,000 individuals), and with an average follow-up period of about 20-25 years.
In summary, results suggest that with a one per cent substitution in the diet of saturated fatty acids for polyunsaturated fatty acids, complex carbohydrates or grains, there is a decrease in the risk of coronary artery disease (fatal and non-fatal heart attack) of six to eight per cent when replacing saturated fatty acids like lauric acid or stearic acid, or 10-12 per cent when replacing a saturated fatty acid like palmitic acid.
It is important to remember that prospective, non-interventional studies are useful to demonstrate correlation, but usually do not establish causation in isolation.
Bearing this in mind, it must be emphasised that the effect of substituting saturated fatty acids in this paper were calculated, not measured.
The question, however, is how applicable are the results. I would say very little. No one calculates their precise micronutrient composition and hence would not be substituting one per cent of their calorie intake at any one time.
For those wanting to know how exactly to eat when it comes to levels of saturated and non-saturated fat I would refer people to the various interventional studies on the Mediterranean diet. (The diet emphasises healthy fats such as olive oil, nuts and seeds, fish and other natural protein sources, fresh fruit and vegetables and whole grains.)
The calculated risk reduction of a one per cent substitution of saturated fat in the diet varies from six to 12 per cent.
The observed risk reduction noted in the Mediterranean diet? Thirty per cent less risk of coronary artery disease and a similar decrease in the risk of diabetes. Personally, I prefer those numbers.
Research score: 2/5