OBJECTIVETo 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.

METHODSAfter 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.

RESULTSNo 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).

CONCLUSIONThe 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.

Adult ; Dietary Carbohydrates ; pharmacology ; Dietary Fats ; pharmacology ; Female ; Gene Frequency ; Genotype ; Health ; Humans ; Lipids ; blood ; Male ; Polymorphism, Single Nucleotide ; Sex Characteristics ; Sterol Regulatory Element Binding Protein 1 ; genetics ; Young Adult

More studies are needed on the hyperyriacylglycerolemic effects of low fat and high carbohydrate (LF-HC) diet in young population, especially Chinese who generally have a diet containing lower fat and higher carbohydrate. To test them in a young Chinese Han population, 56 healthy subjects (22.89±1.80) years were given regular diet of 31% fat and 54% carbohy-drate for 7 days, followed by LF-HC diet of 15% fat and 70% carbohydrate for 6 days, without total energy restriction. After the LF-HC diet, the male experienced an increase of high density lipoprutein (HDL) cholesterol and decreases of weight, body mass index (BMI), total cholesterol (TC), and LDL (low density lipoprotein) cholesterol (P < 0.05). The female experienced in-creased serum triacylglycerol and insulin, and decreased TC and LDL cholesterol (P < 0.05). When BMI was taken into account,all the subjects with low, medium, or high BMI experienced decreases of TC and LDL cholesterol although some changes were not significant. No significant decrease of HDL cholesterol was found, while significantly increased HDL cholesterol and apolipoprotein A-Ⅰ (apo A- Ⅰ) were found in the male subjects with low or high BMI (P < 0.05). Significant increase of triacylglycerol was observed only in the female subjects with low or medium BMI. In conclusion, subjects with different BMI and gender have different triacylglycerol and HDL cholesterol responses to LF-HC diets, and significant increase of HDL cholesterol and apolipoprotein A- Ⅰ were observed in some young male subjects.