RÉSUMÉ
<p><b>OBJECTIVE</b>To investigate the effects of 54G/C polymorphism of sterol regulatory element-binding protein-1c gene (SREBP-1c) on serum lipid ratios and their response to high-carbohydrate/low-fat (HC/LF) diet in healthy youth.</p><p><b>METHODS</b>After a regular diet for 7 days of wash-out, 56 healthy youth (22.89 +/- 1.80 yrs) were given HC/LF diet for 6 days. The regular diet contained 54% carbohydrate, 15% protein, and 31% fat of the total energy. The HC/LF diet contained 70% carbohydrate, 15% protein, and 15% fat of the total energy. The serum lipids and glucose were measured on the 1st, 8th and 14th days. The ratios of TG/HDL-C, log (TG/HDL-C), TC/HDL-C, and LDL-C/HDL-C were calculated. The 54G/C polymorphism of SREBP-1c gene was analyzed by PCR-RFLP method.</p><p><b>RESULTS</b>No significant difference was found in lipid ratios and glucose at baseline and after regular diet in subjects with different genotypes in either the whole studied population or in males or females only. However, after HC/LF diet, LDL-C/HDL-C was significantly lower in females carrying the C allele than those of GG homozygotes (P< 0.05). Compared with those before HC/LF diet, TC/HDL-C and LDL-C/HDL-C were significantly decreased in all the subjects (P< 0.05). When gender was taken into account, significant increase of TG/HDL-C and log(TG/HDL-C) was found only in females with GG genotype (P< 0.05). All the subjects experienced significant decrease of TC/HDL-C and LDL-C/HDL-C regardless of their genders and genotypes (P< 0.05).</p><p><b>CONCLUSION</b>The 54G/C polymorphism of SREBP-1c gene can influence the response of TG/HDL-C and log(TG/HDL-C) to HC/LF diet in females. The C allele may be a protective factor to prevent the increase of TG induced by HC/LF diet in females.</p>