Vitamin C and DNA

67 维生素C能否破坏DNA¹？

DATE=7-11-01
TITLE=SCIENCE REPORT - Vitamin C and DNA
BYLINE=Nancy Steinbach

(Start at 59") is is Bill White with the VOA Special English Science Report.
Millions of Americans take large amounts of (1) vitamin C (2) pills every day because they believe the vitamin will help them stay healthy.  However, a new study says vitamin C may help produce substances that can damage the cell's (3) genetic² material, (4) DNA. Scientists at the (5) University of Pennsylvania experimented with vitamin C in (6) test tubes.  They published the results in the publication³ Science.
The scientists studied the effects of vitamin C on a substance produced in the body from fat.  That substance is called (7) hydroperoxide.  The hydroperoxide can be changed in a cell into substances that can damage DNA.  The scientists found that vitamin C easily changed the hydroperoxide into the gene-damaging (8) poisons.  Such damage is the first step toward⁴ developing cancer.
However, the scientists said the study does not mean that vitamin C causes cancer. But they said people should probably (9) reconsider taking large amounts of vitamin C pills each day.  They say it is well known that vitamin C is important for human health.  But they say people can get enough vitamin C in the foods they eat.  Earlier studies have shown that eating a lot of fruits, vegetables and grains can (10) reduce the chance of developing both heart disease⁵ and cancer.
Other researchers agreed.  They said the latest study is important in understanding the chemistry of vitamin C.  But they said the study did not (11) involve people. The vitamin C was tested in the laboratory⁶ only.  They said the results might be different in living cells.
Mark Levine is a vitamin C expert at the National Institutes of Health near Washington, D.C.  He also questioned whether a (12) similar study in people would produce the same results. Doctor Levine also said people should get their vitamin C in food instead of taking huge amounts in pills to stay healthy.  He said research does not support taking a lot of vitamin C. 
The United States government says people should get about eighty (13) milligrams of vitamin C each day in the foods they eat.  Studies have shown that the body can not use more than two-hundred milligrams of vitamin C each day.  Medical researchers say that taking vitamin C pills cannot (14) replace the value of eating healthy foods.
This VOA Special English Science Report was written by Nancy Steinbach. This is Bill White.

 
(1) vitamin [ 5vaitEmin ] n.维他命, 维生素
(2) pill [ pil ] n.药丸
(3) genetic [ dVi5netik ] adj.遗传的, 起源的
(4) DNA deoxyribonucleic acid⁷ 脱氧核糖核酸
(5) University of Pennsylvania n.宾夕法尼亚大学
(6) test tubes n.试管
(7) hydroperoxide [ 7haidrEpE5rCksaid ] n.[化]氢过氧化物,过氧化氢物
(8) poison [ 5pCizn ] n.毒药, 毒害
(9) reconsider [ 5ri:kEn5sidE ] v.重新考虑, 重新审议
(10) reduce [ ri5dju:s ] vt.减少, 缩小, 简化, 还原
(11) involve [ in5vClv ] vt.包括, 笼罩
(12) similar [ 5similE ] adj.相似的, 类似的
(13) milligram [ 5mili^rAm ] n.毫克
(14) replace [ ri(:)5pleis ] vt.取代, 替换, 代替

1 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

2 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

3 publication   

n.出版，发行；出版；公布，发表

参考例句：

• They don't think this article is suitable for publication.他们认为这篇文章不宜发表。
• The government has delayed publication of the trade figures.政府已将贸易统计数字延后公布。

4 toward   

prep.对于，关于，接近，将近，向，朝

参考例句：

• Suddenly I saw a tall figure approaching toward the policeman.突然间我看到一个高大的身影朝警察靠近。
• Upon seeing her,I smiled and ran toward her. 看到她我笑了，并跑了过去。

5 disease   

n.疾病，弊端

参考例句：

• The doctors are trying to stamp out the disease.医生正在尽力消灭这种疾病。
• He fought against the disease for a long time.他同疾病做了长时间的斗争。

6 laboratory   

n.实验室，化验室

参考例句：

• She has donated money to establish a laboratory.她捐款成立了一个实验室。
• Our laboratory equipment isn't perfect,but we must make do.实验室设备是不够理想，但我们只好因陋就简。

7 acid   

n.酸；酸性物质；adj.酸的，酸性的

参考例句：

• Handle with care,or the acid may get out.小心轻放，否则酸会溢出来。
• The acid has been eating away the sides of the container.酸腐蚀着容器的四壁。