Palm oil and cardiovascular health: considerations to evaluate the literature critically

Palm oil is obtained from Elaeis guineensis, E. oleifera or the hybrid OxG palm fruits. When crude, it contains high carotenoid concentrations (responsible for the red color), tocopherols and tocotrienols, but most of them are eliminated during its refining. Palm oil main components are palmitic and oleic acids, both near 50%, but their proportion changes depending on the fraction used. Fatty acids absorption and the effect on blood lipid profile depend on the position in the triacylglycerol, especially in the sn-2 position. The location of the monounsaturated or saturated fatty acids varies depending on the type of palm oil or fraction used. We critically review the two main reviews published about palm oil, which analyze 67 publications, and several studies that are more recent. Most of the studies were performed in non-European countries where palm oil is the main culinary oil. The effect on cardiovascular risk factors depends on the fat used as counterpart. Palm oil improves lipid profile after a diet rich in trans and saturated fats, while it impairs lipid profile after a diet rich in monounsaturated and polyunsaturated fats. Relevant methodological errors have been identified, such as not differentiating between palm oil, palm kernel oil and their fractions, comparing single fatty acids with whole oils or fats, or not considering physical activity or other factors that can affect blood lipids. No studies considering palm oil as an ingredient in a Mediterranean diet context, where olive oil is the main culinary oil, were found, so extrapolation of data is currently very difficult.