HOMOCYSTEINE DIET STUDY: EFFECTS OF DIFFERENT FOLATE SOURCES

本研究的目的是在同型半胱氨酸水平中度升高的研究人群中，确定三种不同来源的叶酸摄入量对血浆同型半胱氨酸水平的影响。这三个来源将是（1）B族维生素补充剂，（2）叶酸强化食品，（3）天然富含叶酸的食品。受试者将被分配到这三个组之一，或安慰剂组，安慰剂组将接受非活性安慰剂。研究持续时间为12周。前6周每周测量一次同型半胱氨酸水平，然后在第9周测量，并在第12周研究结束时再次测量。因此，我们不仅要研究干预措施引起的变化的程度，而且要研究时间进程。本门诊研究将利用GCRC设施进行与血样采集、等分和样本储存相关的患者护理。参与者将根据每周营养研讨会的指示提供自己的叶酸食物来源。接受B族维生素补充剂或安慰剂的两组将在整个12周内提供片剂。由于食用富含叶酸的食物（非叶酸强化食物）的人群可能会增加纤维和其他潜在的降胆固醇膳食剂的摄入量，我们还将在第1周、第6周和第12周测量血浆胆固醇。作为依从性的衡量标准，我们还将测量血浆叶酸水平。含义：对于那些被建议增加叶酸摄入量的高同型半胱氨酸血症患者，这将有助于确定增加叶酸的几种方法中哪一种最有效。

The study objective is to determine the effect of three different sources of folic acid (folate) intake on plasma homocysteine levels in a study population with moderately elevated homocysteine levels. The three sources will be (1) a B-vitamin supplement, (2) foods fortified with folic acid, and (3) foods naturally abundant in folic acid. Participants will be assigned to one of these three groups, or a placebo group who will receive in inactive placebo. Study duration will be 12-weeks. Homocysteine levels will be measured weekly for the first 6 weeks, then at week #9 and again at end study at week #12. Therefore, we will study not only the magnitude of the change elicited by the intervention, but also the timecourse. This outpatient study will make use of the GCRC facilities for patient care related to blood sampling, aliquoting, and storing of samples. Participants will provide there own food sources of folate, according to instructions received in weekly nutrition workshops. The two groups receiving either B-vitamin supplementation or placebo will be provided with tablets for the full 12-weeks. Since the group consuming folate rich foods (not folate fortified foods) is likely to increase their intake of fiber and other potential cholesterol lowering dietary agents, we will also measure plasma cholesterol at weeks #1, #6 and #12. As a measure of compliance, we will measure plasma folate levels as well. Implications: For individuals with hyperhomocysteinemia who have been advised to increase their folate intake, this will help to determine which of several approches for increasing folate is most effective.