Dietary fats, carbohydrates and vascular disease: Sri Lankan perspectives

The recent estimates for mortality from cardio and cerebrovascular diseases (CVD) for Sri Lanka--524 deaths per 100,000--is higher than that observed in many Western economies. However, neither an excessive total fat intake nor an increase in the more traditional plasma lipid markers, total and LDL cholesterol (LDL-c) levels may fully explain the increased vulnerability to CVD in this population. The average total fat intake of Sri Lankans is 25 percent of total energy (en%) and the reported total and LDL-c values are 4.9 and 2.5 mmol/l, respectively. With regard to the type of dietary fatty acids, the ratio of saturated/polyunsaturated fatty acids (PUFAs) in the average Sri Lankan diet is 9/1 as compared with the current recommended ratio of <1/1. In spite of an adequate total fat intake (25 en%), the relatively low intake of PUFAs in association with a high carbohydrate diet (65 en%), appear to be resulting in similar metabolic outcomes to those of very low fat diets (VLFD, < 15 en% from fat), as reflected by high triglycerides and low HDL levels. Metabolic abnormalities including elevated postprandial hyperlipidemia, more atherogenic lipoprotein particles, hyperglycemia with resultant hyperinsulinemia and increased oxidative stress are likely to be more relevant in such settings. The application of novel biomarkers for example, lipoprotein measurements in the postprandial state, LDL particle size, estimates of endothelial dysfunction, soluble markers of inflammation and coagulability status may provide further insight into cardiovascular disease states in populations where the dietary matrix represents high intakes of highly digestible carbohydrates and saturated fat.