Variation of hdl subclass pattern during dietary intervention in subjects with markers for insulin resistance

HDL cholesterol (C) is an established negative risk factor for cardiovascular disease. Low levels of HDLC, often associated with insulin resistance, are frequently seen in subjects with high plasma triglycerides (TG). To study dietary effects on HDLC levels and HDL subclass pattern, 86 subjects with low HDLC and/or high TG and/or high insulin levels were recruited for a dietary study using the DELTA multicenter randomized 3-way crossover design. Each subject consumed three different diets for 7 weeks; an average American diet, AAD (36% total fat (TF); 16% saturated fat (SFA); 14% monounsaturated fat (MUFA); 48% carbohydrate (CHO)); the AHA Step I diet (29% TF; 8% SFA; 15% MUFA; 55% CHO); and a high MUFA diet (36% TF; 9% SFA; 21% MUFA; 48% CHO). HDLC levels (mg/dl) fell in a step-wise fashion as dietary SFA and TF were reduced (AAD: 42.5; MUFA: 40.8; Step I: 39.3). HDL2 levels (mg/dl) decreased in parallel with overall HDLC levels (AAD: 17.8; MUFA: 16.9; Step I: 16.1). HDL3 levels did not differ between AAD and MUFA, but were lower during the Step I diet. Thus, changes in HDL2 levels reflected changes in HDLC when reducing TF and SFA in subjects at risk for hyperTG or diaTjetes; the effect of the high MUFA diet was less pronounced than that of the Step I diet.