HIGH DENSITY LIPOPROTEINS--BIOMARKERS OF LOW-FAT DIET

准确、客观地评估膳食营养状况的生化指标 脂肪摄入量是必要的，以调查膳食脂肪之间的联系， 和癌症膳食脂肪影响血浆中 脂蛋白传统上，血浆总量和低密度的减少 脂蛋白（LDL）胆固醇用于评估依从性。最近的数据 从我们的实验室，在妇女中获得，表明，高的变化， 密度脂蛋白（HDL），尤其是HDL 2亚组分，提供更多的 关于膳食脂肪的短期和长期的直接信息。 LDL和脂肪摄入之间的关系可能是间接的， 与体重和脂肪量的变化有关。最近的一份报告还 表明高密度脂蛋白是女性脂肪摄入量的最佳预测因子， 而低密度脂蛋白则存在于男性体内。 目前提案的假设是：1。血脂变化 HDL的浓度和颗粒大小与 膳食脂肪，2. HDL的脂肪酸组成反映了 膳食脂肪，3. HDL的组成，脂质和蛋白质的比例 其他，反映了脂肪摄入量，独立于个体间 HDL浓度的变化。4.在短期内高密度脂蛋白的变化- 限制的变化与长期的变化相似。 因此 本研究指定的生物标志物是：游离胆固醇、胆固醇 酯、甘油三酯、磷脂、脱辅基蛋白A1、粒度和脂肪 高密度脂蛋白的酸性成分，包括HDL 2和HDL 3。脂蛋白 脂肪酶和血浆胆固醇酯转移蛋白也被命名为 标记物，因为它们在HDL和其他蛋白质之间交换脂质和载脂蛋白。 脂蛋白 实验设计建议研究64名健康的绝经后妇女， 妇女每个人都被研究了12个月;在一个控制性的低脂肪- 喂养（4个月）和自选低脂喂养（8个月）期。 在控制喂养期间，由研究提供食物。剂量 测试HDL对脂肪摄入减少和增加的反应 通过从基线水平逐步减少到25%，然后减少到15%， 然后又回到25%。时间进程由血液测试确定 在每次饮食改变后2周和4周。长期重现性 在自选的15%脂肪饮食中进行测试，使用商业上的 8个月的食品。HDL的预测值是 也与其他标志物相比;即总胆固醇和LDL-胆固醇， 载脂蛋白B、血小板和血浆的脂肪酸组成。生物计量 也可以使用可以影响生物标志物响应的测量。 确定;即体重，腰臀比，身体成分，休息 能量消耗调查将提供全面的 关于HDL作为膳食脂肪摄入量标志物的价值的信息， 绝经后妇女。

Biochemical markers which accurately and objectively assess the dietary fat intake are necessary to investigate the connection between dietary fat and cancer. Dietary fat influences the concentrations of plasma lipoproteins. Traditionally, decreases in plasma total and low density lipoprotein (LDL) cholesterol are used to assess compliance. Recent data from our laboratory, obtained in women, suggest that changes in high density lipoproteins (HDL), especially HDL2 subfraction, provide more direct information about the dietary fat in short as well as long-term. The relationship between LDL and fat intake may be an indirect one, related to the changes in body weight and fat mass. A recent report also demonstrates that HDL is the best predictor of fat intake in women, whereas LDL is in men. The hypotheses of the Current Proposal are; 1. Changes in lipid concentration and particle size of HDL correlate with the changes in dietary fat, 2. Fatty acid composition of HDL reflects the quality of dietary fat, 3. Composition of HDL, ratios of lipid and protein to each other, reflects the amount of fat intake, independent of inter-individual variations in HDL concentrations. 4. Changes in HDL during short-term fat- restriction are similar to the changes in the long-term. Accordingly, the designated biomarkers of the study are; free-cholesterol, cholesteryl ester, triglyceride, phospholipid, apoprotein Al, particle size and fatty acid composition of HDL, including HDL2 and HDL3. Adipose-lipoprotein lipase and plasma cholesterol ester transfer protein are also designated markers, since they exchange lipids and apoproteins between HDL and other lipoproteins. The experimental design proposes studying 64 healthy, post-menopausal women. Each person is studied for 12 months; during a Controlled Low-Fat- Feeding (4-months) and a Self-Selected Low-Fat-Feeding (8-months) period. During the Controlled-Feeding, food is provided by the study. Dose response of HDL both to a decrease and an increase in fat-intake is tested by a step wise reduction from the baseline level to 25% and then to 15%, followed by a return to 25%. The time course is determined by blood tests at 2 and 4 weeks after each dietary change. The long-term reproducibility is tested during a Self-Selected 15%-fat diet, using commercially available food products for 8 months. The predictive value of the HDL is also compared with other markers; i.e. total and LDL-cholesterol, apoprotein B, fatty acid composition of platelets and plasma. Biometric measurements which can influence the response of biomarkers are also determined; i.e. weight, waist to hip ratio, body composition, resting energy expenditure. The proposed investigation will provide comprehensive information about the value of HDL as a marker of dietary fat intake in post-menopausal women.