An overview of the nutritional significance of the sn-2 position

The conventional concept of saturation and unsaturation should not be used as the only consideration in determining the nutritional effects of oil and fats. Studies have shown that the type of fatty acids in the sn-2 position is critical in determining the bioavailability and digestibility of the oil and fats. Fats Fom plants such as Palm Oil and Cocoa Butter generally have the palmitic acid distributed in the sn-1 and sn-3 position while the sn-2 position is mainly filled with oleic acid. Studies have shown that these natural fats rich in palmitic-oleic fatty acids behave similar to monounsaturates. Animal fats such as lard, despite having a similar fatty acid composition as Palm Oil but has palmitic acid predominantly in the sn-2 position, has been proven to be cholesterolaemic. In the recent years, as Trans fatty acids became an issue among many food manufacturers, interesterification of oil and fats is increasingly used as an alternative to the partial hydrogenation, either by enzymatic or chemical interesterification. The effect of chemical interesterification on the cardiovascular and blood sugar level is still uncertain. Preliminary evidence from a study using a stearic rich interesterified fat has resulted in anincrease in the post prandial glucose and the LDL/ HDL ratio. However recent studies with chemically interesterfied palm oil produced lower plasma triglyceride when compared to nativepalm oil and high oleic sunflower oil. Possible explanations suggest that this could be due to the differences in rate of absorption, lipolysis and/or clearance. Further research is warranted tounderstand the mechanisms involved in the metabolism of oil and fats.