Particle size of LDL is affected by the National Cholesterol Education Program (NCEP) step II diet in dyslipidaemic adolescents.

The objective was to determine the effects of the National Cholesterol Education Program (NCEP) step II diet on LDL and HDL particle size in dyslipidaemic adolescents. Forty-four dyslipidaemic adolescents, aged 10-18 years, participated in this case-control study. The control diet was a diet similar to what most Tehranian adolescents eat. NCEP step II diet was a diet with 30 % of energy as total fat, less than 7 % saturated fat, less than 200 mg cholesterol/d, less than 15 % of energy as MUFA and less than 10 % as PUFA. Lipoprotein particle size was the major outcome variable, which was measured after 3 months of intervention. Comparison was made by the repeated measurement ANOVA. The mean BMI was 26.3 (sd 4.2) kg/m2. There were no significant changes in weight or physical activity in the two groups during the study. The NCEP diet resulted in higher reduction in total cholesterol ( - 13 (sd 4) v. - 2 (sd 0.3) mg/dl, P < 0.001) and LDL ( - 9 (sd 2) v. 3 (sd 0.6) mg/dl, P < 0.01), and higher increase in size of the LDL (1.7 (sd 0.4) v. 0.1 (sd 0.4) nanometer, P < 0.001). HDL particle size did not change significantly. NCEP step II diet had a favourable effect on the LDL particle size. The related mechanism needs to be studied in future experimental designs.