HIGH DENSITY LIPOPROTEINS--BIOMARKERS OF LOW-FAT DIET

准确客观地评价膳食的生化标志物 脂肪摄入量是研究饮食脂肪之间的联系所必需的 和癌症。膳食脂肪影响血浆浓度 脂蛋白。传统上，血浆总密度和低密度的减少 脂蛋白(LDL)胆固醇被用来评估依从性。最新数据 从我们的实验室，在女性中获得的，表明变化在高 密度脂蛋白(HDL2)，尤其是HDL2亚组分，提供更多 关于饮食脂肪的直接信息，无论是短期还是长期。 低密度脂蛋白与脂肪摄入量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预测女性脂肪摄入量的最佳指标， 而低密度脂蛋白存在于男性体内。 目前建议的假设是：1.血脂的变化 高密度脂蛋白的浓度和颗粒大小与 膳食脂肪，2.高密度脂蛋白的脂肪酸组成反映了 膳食脂肪，3.高密度脂蛋白的组成，脂肪和蛋白质的比例 其他，反映脂肪摄入量，独立于个体间 高密度脂蛋白浓度的变化。4.短期肥胖过程中高密度脂蛋白的变化 限制也类似于长期的变化。因此， 这项研究的指定生物标记物是：游离胆固醇、胆固醇 酯、甘油三酯、磷脂、载脂蛋白Al、颗粒大小和脂肪 高密度脂蛋白的酸组成，包括高密度脂蛋白2和高密度脂蛋白3。脂脂蛋白 脂肪酶和血浆胆固醇酯转移蛋白也被指定为 标记物，因为它们在高密度脂蛋白和其他 脂蛋白。 实验设计建议研究健康、绝经后 女人。每个人都被研究了12个月；在受控的低脂期间- 喂养(4个月)和自行选择的低脂肪喂养(8个月)。 在控制喂养期间，食物由研究人员提供。剂量 测试了高密度脂蛋白对脂肪摄入量减少和增加的反应 通过从基准水平逐步降低到25%，然后降低到15%， 之后又回升至25%。时间进程是由血液测试确定的 在每次饮食改变后的2周和4周。长期可再生性 在自己选择的15%脂肪饮食中进行测试，使用商业 提供8个月的食品。高密度脂蛋白的预测价值是 也与其他指标进行比较；即总胆固醇和低密度脂蛋白-胆固醇， 载脂蛋白B，血小板和血浆的脂肪酸组成。生物识别 可以影响生物标记物反应的测量也是 确定；即体重、腰臀比、身体成分、休息时间 能源支出。拟议的调查将提供全面的 高密度脂蛋白作为膳食脂肪摄入量标记物的价值 绝经后的女性。

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.