视频文本

As mentioned earlier,
正如我们之前所言
most commonly used supplements have been used in traditional medicine practices.
很多常用的补充剂在传统医学中都有使用
In their original use, herbs were often given in symbolic and ritualistic manners
传统上，草药通常是一种象征带有仪式的意味，
that provide psychological and cultural effects.
它们能够产生心理和文化作用，
Most cultures had a healer who practiced these therapies and was viewed with respect.
大多数文化中都有这样的医师，他们给人们开药并且受到极大的尊重，
It is not possible to expect a pill or a tablet containing an herb to replicate these complex interactions.
幻想一片补充剂中含有的草药成分能够代替这种复杂的活动是不可能的
One mechanism through which many supplements may impact health is by acting as antioxidants.
很多补充剂都是通过充当抗氧化剂来起到促进健康的作用的
Oxidation is a natural event in the human body in which
氧化是人类身体中的一个自然过程，
oxygen interacts with other molecules and causes them to be damaged.
氧气和身体内的其他分子相互作用并使它们受损，
Common targets for oxidation include lipids and membranes,DNA molecules, and proteins.
通常，氧化过程的主要目标是脂质和细胞膜，DNA分子和蛋白质
The body has many defense systems in place to protect from oxidative damage.
人体内有很多防御系统保护人类受到氧化过程的侵害，
These antioxidants include enzymes and chelators
这些抗氧化剂包括酶和螯合剂，
that remove oxygen-containing molecules and repair the damage.
它们可以移除氧化的分子并且对受损的部分进行修复，
Many plants contain natural antioxidants as well which protect the plant cells.
很多植物也含有天然抗氧化物，它们可以保护植物的细胞
The most abundant antioxidants in plant foods are polyphenols.
植物中最常含有的抗氧化剂是多酚，
This is a widely varying class of chemicals
这是一种具有多种形态的化学物质，
that includes carotenoids, lutein, flavonoids, anthocyanins, and catechins.
包括类胡萝卜素，叶黄素，类黄酮，花青素和儿茶素
In plants, some of these compounds provide bright colors of red, yellow, orange, and purple
在植物中，这些物质中的一些能够呈现红色，黄色，橘色和紫色
such as those found in tomatoes, squash, pumpkin, and beets.
比如番茄，南瓜和甜菜，
They are also found in tea and whole grains.
它们也存在于茶和天然谷物中
It is widely thought that the antioxidant activity of these compounds contributes to the health benefits
人们普遍认为，这些成分的抗氧化活动对人体健康有益，
associated with a diet rich in fruits and vegetables.
因此应该多食用水果和蔬菜
You may find advertisements for vegetable extracts or supplements
你或许会在广告中发现一些蔬菜提取物或者补充剂，
that claim to be good sources in these compounds.
声称自己能够提供这些抗氧化剂，
Caution needs to be exercised when considering these products
但是面对这些产品时我们必须要小心
because they are likely to be poorly absorbed from such formulations
因为它们可能并不能很好地被人体吸收，
and may have undergone significant chemical degradation in processing procedures.
并且在生产加工过程中很可能会由于化学过程而使得自身功效受到损害，
The best way to enrich your diet in these compounds
在饮食中添加这些物质的一个最好的方式
is to consume a wide variety of fruits and vegetables.
就是多吃水果和蔬菜

视频及简介

视频简介：

本课程的目标是，向公众提供最新的有关营养方面的信息和话题，内容涵盖饮食因素对于癌症的影响作用，健康的饮食习惯，学校能提供的营养有哪些，咖啡因与癌症的联系，水果蔬菜与癌症预防等。通过本课程的学习，人们可以学习到健康的生活饮食习惯，在每天的饮食中防癌症于未然。