Should the pharmacological actions of dietary fatty acids in cardiometabolic disorders be classified based on biological or chemical function?

Westernised dietary patterns are characterised by an increased intake of saturated (SFA) and trans fat (TFA) and a high n-6:n-3 polyunsaturated fatty acid (PUFA) ratio. These changes together with increased sugar intake have been implicated in the progression and development of metabolic syndrome. It is now recognised that the type of dietary fat plays a far more significant role in well-being than the absolute amount. This has led to the generalisations that TFA and SFA are detrimental, MUFA is neutral and PUFA is cardioprotective. However, different dietary fatty acids even within the same chemical class elicit different physiological responses. Thus, generalising fatty acids by the degree of unsaturation or the configuration of double bonds alone is unlikely to predict biological responses. In this review, we have examined the effects of different dietary fatty acids on the cardiometabolic risk factors and propose a revised classification based on current evidence of biological activity, rather than chemical structure. Specifically, we propose that dietary fatty acids be classified into five classes as neutral, reduce one or more cardiometabolic risk factors, increase one or more cardiometabolic risk factor, controversial evidence to allow classification and inadequate research to allow classification as a basis for further discussions.