HOMOCYSTEINE DIET STUDY: EFFECTS OF DIFFERENT FOLATE SOURCES

同型半胱氨酸是一种血液中发现的因子，在患有心脏病的成年人中被发现会升高，类似于血液中胆固醇水平升高。人们发现，这种心脏病的相对危险因素与膳食维生素叶酸或叶酸有关。饮食中有三种不同的叶酸来源。一种来自典型的复合维生素，另一种来自早餐谷物和其他含有叶酸的食物，第三种来自豆类和绿叶蔬菜，它们的叶酸含量自然很高。本研究的目的是确定这三种叶酸来源中哪一种对降低同型半胱氨酸中度升高的成年人的同型半胱氨酸水平最有效。60名参与者被随机分为四组：复合维生素组、强化食品组、豆类和绿色蔬菜组和安慰剂组。六周后，研究人员发现，服用复合维生素的那组人血液中同型半胱氨酸水平下降得最多。吃强化食品的那一组几乎和吃多种维生素的那一组一样好。吃豆类和蔬菜的那组并不比安慰剂组好，两者的变化都可以忽略不计。对这些来源中叶酸形态的了解或许可以解释观察到的差异。在多种维生素和强化食品中，所使用的叶酸形式是最小的、最容易吸收的形式，而在豆类和蔬菜中，叶酸的形式更大、更复杂，而且不容易吸收。总之，增加饮食中叶酸的两种安全且容易获得的方法对降低升高的同型半胱氨酸水平有效，但增加豆类和蔬菜的日常消费的方法对改善这一特定的心脏病风险因素无效。

Homocysteine is a factor found in blood that has been found to be elevated among adults with heart disease, similar to elevated blood cholesterol levels. This relatively risk factor for heart disease has been found to respond to the dietary vitamin known as either folate or folic acid. There are three different sources of folate in the diet. One is from typical multivitamins, another is from breakfast cereals and others that have been with folate, and a third is from beans and leafy greens, which have naturally high folate levels. The purpose of this study was to determine which of those three sources of folate would be most effective in lowering homocysteine levels in adults with moderately elevated homocysteine. Sixty participants were enrolled and randomly assigned to be in one of four groups: Multivitamin, fortified foods, beans and greens, or a placebo group. After six weeks it was found that blood levels of homocysteine dropped the most for the group taking the multivitamin. The group eating the fortified foods did almost as well as the multivitamin group. The group eating beans and greens did no better than the placebo group, both showed negligible change. Knowledge of the form of folate found in each of these sources might explain the observed differences. In the multivitamins and fortified foods, the form of folate used is the smallest, best absorbed form of folate, whereas in the beans and greens the folate is found in a larger, more complex form, and is not as readily absorbed. In conclusion, two safe and readily available approaches for increasing folate in the diet were effective at lowering elevated homocysteine levels, but the approach of increasing daily consumption of beans and greens was not effective for improving this one particular heart disease risk factor.