According to new US research filling up on leafy green vegetables could be a factor in keeping your brain healthy later in life, thanks to a nutrient¹ called lutein. Carried out by the University of Illinois, the researchers set out to see if there was a notable difference in cognitive² function between younger and middle-age participants with higher and lower lutein levels.

美国的新研究表明：多吃绿叶蔬菜可能会保持你的大脑健康，而这得归因于一种叫做叶黄素的营养物质。伊利诺伊大学的研究人员开展了该项研究，他们想要观察有较高叶黄素水平的年轻受试者和较低叶黄素水平的中年受试者之间的认知功能是否存在明显差异。

Most previous studies have looked at lutein levels in older adults, after there has already been a period of cognitive decline, however the new study recruited 60 participants aged 25 to 45.

先前的大多数研究只观察了老年人的叶黄素水平，而他们的认知功能本就有所衰退，这项新研究招募了60位25至45岁的受试者。

"As people get older, they experience typical decline. However, research has shown that this process can start earlier than expected. You can even start to see some differences in the 30s," said Anne Walk, first author of the paper. "We want to understand how diet impacts cognition throughout the lifespan. If lutein can protect against decline, we should encourage people to consume lutein-rich foods at a point in their lives when it has maximum benefit."

"随着人们年龄的增长，他们会经历一些典型的衰退。然而，研究表明：这一过程可能比预期更早。有些人30岁的时候就能看出差异了，"该文章的第一作者安妮·沃克（Anne Walk）说道。"我们想要了解在整个生命周期中，饮食对人们认知的影响。如果叶黄素能防止认知功能衰退，我们就应该鼓励人们在生命中的某个阶段多吃一些富含叶黄素的食物，因为这个阶段能带来最大的益处。"

Lutein is a nutrient that the body can't make on its own but it can be acquired through diet. As well as green leafy vegetables such as spinach³ and kale, it is also found in foods such as avocados and eggs. To measure levels of the nutrient in the participants the researchers looked at the participants' eyes, where lutein accumulates in the tissue, asking them look into a scope and respond to a flickering⁴ light.

叶黄素是身体自身无法产生的营养物质，但却可以通过饮食获得。菠菜、羽衣甘蓝等绿叶蔬菜以及牛油果、鸡蛋等食物都含有叶黄素。为了测量受试者体内的叶黄素水平，研究人员检查了受试者的眼睛，因为叶黄素积累在眼睛的组织中，并让他们看向一个区域，对闪光灯做出反应。

While the participants performed a task to measure their attention, the researchers used electrodes on the scalps to measure neural⁵ activity in the brain.

虽然受试者参加了测量他们注意力的任务，但研究员也在他们的头皮上使用电极测量他们的大脑活动。

The results showed that, "The neuro-electrical signature of older participants with higher levels of lutein looked much more like their younger counterparts than their peers with less lutein," explained Walk, adding that, "Lutein appears to have some protective role, since the data suggest that those with more lutein were able to engage more cognitive resources to complete the task."

结果表明，"相比叶黄素水平较低的年纪较大的那些人，那些叶黄素水平较高的同龄人的神经电学特征与年纪较小的受试者更相似，"沃克解释道，并补充说，"叶黄素似乎能起到保护作用，因为数据显示那些叶黄素水平较高的人能够动用更多的认知资源完成任务。"

"Now there's an additional reason to eat nutrient-rich foods such as green leafy vegetables, eggs and avocados," concluded Naiman Khan, a professor of kinesiology and community health at Illinois. "We know these foods are related to other health benefits, but these data indicate that there may be cognitive benefits as well."

"这又给了人们一个多吃营养丰富的食物的理由，比如多吃绿叶蔬菜、鸡蛋和牛油果，"伊利诺伊大学的运动学和社区健康学教授奈曼·汗总结道。"我们知道这些食物还有其它的健康益处，但这些数据表明它们也可能带来认知益处。"