This year the jury has been out when it comes to saturated fats.
While health officials have continued to warn a diet high in sat fats is bad for us, some studies have suggested saturated fat in butter is no worse for us than vegetable oil.
Now, a new large-scale study may have settled the issue once and for all.
The research involving more than 115,000 people found that consumption of major saturated fatty acids increases an individual’s risk of coronary heart disease.
Researchers from Harvard University suggested these should be replaced with unsaturated fats, whole grain carbohydrates or plant proteins, as part of an effective preventive approach.
The findings, published in the British Medical Journal, show that a higher intake of major saturated fatty acids, such as those found in hard cheese, whole milk, butter, beef and chocolate, was associated with an increased risk of coronary heart disease.
Replacing 1% of the daily energy intake from these saturated fats with equivalent energy from polyunsaturated fats, monounsaturated fats, whole grain carbohydrates, or plant proteins, was estimated to reduce coronary heart disease risk by 6-8%.
“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,” the researchers said.
They analysed data from two large US studies that involved more than 73,000 women and more than 42,000 men. Dietary intake among participants was recorded every four years, along with incidence of coronary heart disease. Deaths were identified by searching the National Death Index or through next of kin.
All participants were free from major chronic conditions and the study adjusted for a range of factors that may have influenced the results, such as lifestyle choices (e.g. smoking).
The results showed that the most commonly consumed major saturated fatty acids were lauric acid, myristic acid, palmitic acid and stearic acid, which accounted for around 9-10% of total energy in the participants.
Each of these saturated fatty acids was associated with an increased risk of coronary heart disease.
In an accompanying editorial, Canadian experts Russell de Souza and Sonia Anand said it’s important to focus on a general healthy diet, rather than on specific nutrients, because “dietary patterns might be more consistent with how people consume nutrients and these patterns can predict heart disease risk”.
They said that a focus on saturated fatty acids might result in diet that meets one target, for example, low in saturated fat, but fails to meet another, because of a high intake of refined carbohydrates.
They added that dietary patterns have been advocated by national guidelines and “these new directions are a welcome improvement over single nutrient targets which, although of interest to nutrition scientists, are often confusing for the public, and undermine the effectiveness of dietary guidance”.