|
67 维生素C能否破坏DNA？
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) genetic material, (4) DNA. Scientists at the (5) University of Pennsylvania experimented with vitamin C in (6) test tubes. They published the results in the publication 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 toward 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 disease 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 laboratory 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 acid 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
|