[Effects of the 54G/C polymorphism of sterol regulatory element-binding protein-1c on changes of serum lipid ratios induced by high-carbohydrate/low-fat diet in healthy youth].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

No decrease of HDL cholesterol after 6 days of low fat and high carbohydrate diets in a young Chinese Han population.

More studies are needed on the hypertriacylglycerolemic 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% carbohydrate 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 lipoprotein (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 increased 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.

[Effects of high-carbohydrate/low-fat diet on serum lipid ratios in healthy young subjects].

OBJECTIVE: To investigate the effects of the short-term high-carbohydrate/low-fat (HC/LF) diet on the serum lipid ratios of healthy young subjects, which meant triglyceride to high-density lipoprotein cholesterol (TG/HDL-C), the logarithm of TG/HDL-C [log (TG/HDL-C)], low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL-C/HDL-C), and total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C). METHODS: 56 healthy participants with the average age of (22.89 +/- 1.80) years took the normal diet for 7 days followed by HC/LF diet for 6 days. Venous blood samples in fasting were collected between 7 : 00 and 10 : 00 AM on the 1st, the 8th and 14th day, respectively. Serum concentrations of triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C) were measured by regular methods. The ratios of TG/HDL-C, log (TG/HDL-C), LDL-C/HDL-C, and TC/ HDL-C were calculated. RESULTS: After HC/LF diet, both TG/HDL-C and log (TG/HDL-C) increased significantly for females (P < 0.05). For the males, these two ratios were decreased although not significant in statistics. When BMI or WHR was taken into account, the two ratios increased significantly after HC/LF diet, but only for the normal females (P < 0.05), not for the females with overall or abdominal adiposity. No significant changes of TG/HDL-C and log(TG/HDL-C) after HC/LF diet were observed between the males with different BMI or WHR. TC/HDL-C and LDL-C/HDL-C decreased significantly (P < 0.05) after HC/LF diet, but these changes were not found to associate with gender, BMI or WHR. CONCLUSION: The changes of TG/HDL-C and log (TG/HDL-C) induced by the short-term HC/LF diet are different in healthy young subjects with different gender, BMI or WHR, but there is no significant change happening to TC/HDL-C and LDL-C/HDL-C.

[Effects of a high-carbohydrate, low-fat diet on the levels of serum phospholipids and triglycerides].

OBJECTIVE: To study the effects of a High-carbohydrate, Low-fat (HC/LF) diet on the levels of phospholipids and triglycerides in serum and analyze their association with anthropometric indexs and serum biochemical traits. METHODS: 56 healthy volunteers had a HC/LF diet for 6 days. The body weight, waist circumference, hip circumference, biceps circumference, and skinfold thickness were measured before and after the HC/LF diet. Venous blood was taken after fasting of 12 hours. The levers of high density lipoprotein-phospholipid (HDL-PL), high density lipoprotein-triglyceride (HDL-TG), high density lipoprotein-cholesterol (HDL-C) were enzymatically determined after precipitation of serum apoB containing lipoproteins with phosphotungistic acid and non-LDL-phospholipid (NLDL-PL), non-LDL-triglyceride (NLDL-TG), non-LDL-Cholesterol (NLDL-C) levels were enzymatically determined after precipitation of serum LDL with polyethylene sulfate. The levels of serum LDL-PL, LDL-TG, and LDL-C were calculated by minus of non-LDL from serum PL, TG, and TC levels, respectively. The level of TRL-TG was calculated by minus of HDL-TG, LDL-TG from total TG. The level of serum insulin was measured by electrochemical luminescence. RESULTS: The levels of fasting serum PL, HDL-PL and LDL-PL decreased significantly after HC/LF diet, whereas the levels of TG, HDL-TG and insulin increased. Correlation analyses indicated that after HC/LF diet the change of serum PL (APL) had a negative correlation with the change of BMI(deltaBMI),a positive correlation with the change of HDL-TG(deltaHDL-TG) and insulin (delta insulin). The change of serum LDL-PL (deltaLDL-PL) had a negative correlation with deltaBMI and waist circumference (deltaAWC), meanwhile the change of HDL-PL (deltaHDL-PL) had a negative correlation with deltaHDL-TG, a positive correlation with the change of HDL-C (deltaHDL-L). A positive correlation existed between deltaHDL-TG and wais/hip circumference ratio (deltaW/H). CONCLUSION: HC/LF diet can decrease serum PL, HDL-PL level but increase serum levels of TG and insulin. The change of serum PL level had a negative correlation with deltaBMI,a positive correlation with deltaHDL-TG and delta insulin.