Objective: To investigate the effects of cholesterol ester transfer protein gene (CETP) TaqIB polymorphism on serum lipid ratios and their responses to high-carbohydrate/low-fat (HC/LF) diet in healthy youth.
Methods: After on regular diet for 7 days, 56 health youth [(22.89+/-1.80) years] were given HC/LF diet for 6 days. The regular diet contained 54% carbohydrate, 15% protein, and 31% fat of the total energy. The LF/HC diet contained 70% carbohydrate, 15% protein, and 15% fat of the total energy. The serum lipids were measured on the 1st, the 8th and the 14th day. The ratios of TG/HDL-C, log (TG/HDL-C), TC/HDL-C, and LDL-C/HDL-C were calculated. The polymorphism of CETP was analyzed by PCR-RFLP method.
Results: No significant difference was found of the lipid ratios at baseline in subjects with different genotypes in both genders. After the regular diet, TC/HDL-C was significantly lower in males carrying the B2 allele than B1B1 homozygotes (P<0.05). After HC/LF diet, no significant difference was found of the lipid ratios between the subjects with different genotypes in the whole study population or in males and females separately. Compared with those before HC/LF diet, subjects with B1B1 genotype experienced significant changes of the four lipid ratios after HC/LF diet (P<0.05), while the B2 carriers had only significant decrease of TC/HDL-C and LDL-C/HDL-C (P<0.05). No significant difference of the changes of the four lipid ratios before and after HC/LF diet was found between the subjects with different genotypes. When gender was taken into account, significant increases of TG/HDL-C and log (TG/HDL-C) were found in females with B1B1 genotype (P<0.05). All the subjects experienced significant decrease of TC/HDL-C and LDL-C/HDL-C regardless of gender and genotype (P<0.05). As for the changes of lipid ratios before and after HC/LF diet, difference of only TC/HDL-C was found between males with B1B1 and male carriers of B2 (P<0.05).
Conclusion: Polymorphism of CETP TaqIB may influence the response of TC/HDL-C to HC/LF diet in males and the increases of TG/HDL-C and log (TG/HDL-C) induced by HC/LF diet in females.