SCIENCE IN THE NEWS - From A to Zinc: The Story of Vitamins

SCIENCE IN THE NEWS - From A to Zinc¹: The Story of Vitamins
By Nancy Steinbach

Broadcast: Tuesday, March 29, 2005

(MUSIC)

VOICE ONE:

I'm Bob Doughty² with Phoebe Zimmermann, and this is the VOA Special English program SCIENCE IN THE NEWS.

VOICE TWO:

This week, a special report all about vitamins. We tell about some of the common ones needed for good health.

(MUSIC)

VOICE ONE:

Many jobs must be done with two people. One person takes the lead. The other helps. It is this cooperation that brings success.

So it is with the human body. Much of our good health depends on the cooperation between substances. When they work together, chemical reactions take place smoothly³. Body systems are kept in balance.

Some of the most important helpers in the job of good health are the substances we call vitamins.

 
 
VOICE TWO:

The word "vitamin" dates back to Polish scientist Casimir Funk in nineteen-twelve. He was studying a substance in the hull⁴ that covers rice. This substance was believed to cure the nervous system disorder⁵ beriberi.

Funk believed the substance belonged to a group of chemicals known as amines [uh-MEENS]. He added the Latin "vita" meaning life. So he called the substance a "vitamine" [vita-MEEN] -- an amine necessary for life.

Funk was not able to separate the anti-berberi substance from the rice hulls⁶; it turned out to be thiamine. And later research showed that not all vitamines were amines after all. So the name was shortened to vitamin. But Funk was correct in recognizing the importance.

VOICE ONE:

Scientists have discovered fourteen kinds of vitamins. They are known as vitamins A, the B group, C, D, E and K. Scientists say vitamins act like enzymes⁷. They help carry out chemical changes within cells.

If we do not get enough of the vitamins we need in our food, we are likely to develop a number of diseases.

This brings us back to Polish scientist Casimir Funk and his studies of rice. His experiments were part of a long search for foods that could cure disease.

VOICE TWO:

One of the first people involved in that search was James Lind of Scotland. In the seventeen-forties, Lind was a doctor for the British Navy. He was trying to solve a problem the Navy had been suffering for hundreds of years. The problem was the disease scurvy⁸. So many British sailors had scurvy that the Navy's fighting strength was very low.

The sailors were weak from continuous bleeding inside their bodies. Their teeth fell out. Even the smallest wound would not heal. Doctor Lind thought the sailors were getting sick because they were unable to eat some kinds of foods when they were at sea for many months.

Doctor Lind divided twelve sailors suffering from scurvy into two groups. He gave each group different foods to eat. One group got oranges and lemons. The other did not.

The men who ate the fruit began to improve within seven days. The other men got weaker and weaker.

Doctor Lind was correct. Eating citrus fruits prevents scurvy.

VOICE ONE:

Other doctors searched for foods that would cure rickets⁹ and pellagra. They did not yet understand that they were seeing the problem backwards¹⁰. That is, it is better to eat vitamin-rich foods to prevent disease instead of eating them to cure disease after it has developed.

Just how do vitamins keep us healthy? Which foods are the best source for different ones? Let us look at some important vitamins for these answers.

(MUSIC)

VOICE TWO:

Vitamin A is needed to produce a light-sensitive substance in the eyes. And it helps prevent skin and other tissues from drying out. People who do not get enough vitamin A cannot see well in the dark. They also may develop a condition that dries the eyes, called xerophthalmia [zir-af-THAL-mea]. It can result in infections and lead to blindness.

The best source of vitamin A is fish liver oil. It also is found in the yellow part of eggs. In addition, squash, sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into vitamin A.

VOICE ONE:

Vitamin B-one is also called thiamine. It changes starchy foods into energy. It also helps the heart and nervous system work smoothly. Without it, we would be weak and would not grow. We also might develop beriberi.

Thiamine is found not just in whole grains like brown rice, but also in other foods. These include beans and peas, nuts, and meat and fish.

Another B-vitamin is niacin. It helps cells use food energy. It also prevents pellagra, a disease that causes weakness, red skin and stomach problems. Good sources of niacin are meat, fish and green vegetables.

Vitamin B-twelve is needed so folic acid can do its work. Together, they help produce red blood cells. Without them, a person suffers from anemia¹¹.

Vitamin B-twelve is found naturally in foods such as eggs, meat, fish and milk products. Folic acid has been shown to prevent birth defects when taken by women of child-bearing age. It is found in green leafy vegetables and other foods including legumes and citrus fruits. It is also added to enriched breads and other products.

The first vitamin discovery in the twenty-first century was made by Japanese researchers in April of two-thousand-three.

They identified a new member of the B-vitamin group. It is a substance known since nineteen-seventy-nine: pyrroloquinoline quinone [pi-RO-lo-QUI-no-leen qui-NOHN], or PDQ. The researchers found that it plays an important part in the reproductive and defense¹² systems in mice. They said the substance is similarly important for people. PDQ is found in fermented¹³ soybeans and also in parsley, green tea, green peppers and kiwi fruit.

VOICE TWO:

Vitamin C is necessary for strong bones and teeth, and for healthy blood vessels¹⁴. It also helps wounds heal quickly. The body stores very little vitamin C. So we must get it every day in foods such as citrus fruits, tomatoes and uncooked cabbage.

Vitamin D increases the amount of calcium¹⁵ in the blood. Calcium is needed for nerve and muscle cells to work normally. It also is needed to build strong bones.

Vitamin D prevents a children's bone disease called rickets. Ultraviolet rays from the sun change a form of cholesterol¹⁶ in the skin into vitamin D. Another source is fish liver oil. In some countries, milk producers add vitamin D to milk, especially so children will get enough.

Vitamin K is needed for healthy blood. It thickens the blood around a cut to stop bleeding. Bacteria in the intestines¹⁷ normally produce vitamin K. It can also be found in pork and liver and in vegetables like cabbage, kale and spinach¹⁸.

(MUSIC)

VOICE ONE:

So, how do we know how much of each vitamin we need every day? Public health agencies publish lists of suggested amounts.

But some people take pills each day that contain larger amounts of vitamins. They think the extra vitamins will improve their health and protect against disease. Some doctors agree. But many do not. For one thing, they point out that too much of some vitamins can be harmful to healthy people.

For example, too much vitamin A can lead to the bone weakening condition osteoporosis. Too much vitamin B-six can damage the nervous system, causing a loss of feeling in the arms and legs. Too much vitamin E can increase the chances of developing a heart attack or stroke.

VOICE TWO:

Doctors say only people who know that they lack a vitamin should take extra amounts in pills. Some older people, for example, may not have enough vitamin B-twelve. That is because, as people get older, the body loses its ability to take it from foods.

Also, people who do not go outdoors much may need extra vitamin D since the skin makes this vitamin from sunlight.

And, women who may become pregnant need to make sure they get enough folic acid to protect the baby from possible birth defects.

VOICE ONE:

Vitamins are important to our health. But different vitamins are found in different foods -- grains, vegetables and fruits, fish and meat, eggs and milk products. And even foods that contain the same vitamins may have them in different amounts. Nutrition experts say this is why it is important, where possible, to eat a mixture of foods every day, to try to get enough of the vitamins our bodies need.

(MUSIC)

SCIENCE IN THE NEWS was written by Nancy Steinbach and produced by Cynthia Kirk. This is Bob Doughty.

VOICE TWO:

And this is Phoebe Zimmermann. Join us again next week for more news about science in Special English on the Voice of America.

1 zinc   

n.锌；vt.在...上镀锌

参考例句：

• Brass is formed by the fusion of copper and zinc.黄铜是通过铜和锌的熔合而成的。
• Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。

2 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

3 smoothly   

adv.平滑地，顺利地，流利地，流畅地

参考例句：

• The workmen are very cooperative,so the work goes on smoothly.工人们十分合作，所以工作进展顺利。
• Just change one or two words and the sentence will read smoothly.这句话只要动一两个字就顺了。

4 hull   

n.船身；(果、实等的)外壳；vt.去(谷物等)壳

参考例句：

• The outer surface of ship's hull is very hard.船体的外表面非常坚硬。
• The boat's hull has been staved in by the tremendous seas.小船壳让巨浪打穿了。

5 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

6 hulls   

船体( hull的名词复数 )； 船身； 外壳； 豆荚

参考例句：

• Hulls may be removed by aspiration on screens. 脱下的种皮，可由筛子上的气吸装置吸除。
• When their object is attained they fall off like empty hulls from the kernel. 当他们的目的达到以后，他们便凋谢零落，就象脱却果实的空壳一样。

7 enzymes   

n. 酶，酵素

参考例句：

• It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
• Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。

8 scurvy   

adj.下流的，卑鄙的，无礼的；n.坏血病

参考例句：

• Vitamin C deficiency can ultimately lead to scurvy.缺乏维生素C最终能道致坏血病。
• That was a scurvy trick to play on an old lady.用那样的花招欺负一个老太太可真卑鄙。

9 rickets   

n.软骨病，佝偻病，驼背

参考例句：

• A diet deficient in vitamin D may cause the disease rickets.缺少维生素D的饮食可能导致软骨病。
• It also appears to do more than just protect against rickets.除了防止软骨病，它还有更多的功能。

10 backwards   

adv.往回地，向原处，倒，相反，前后倒置地

参考例句：

• He turned on the light and began to pace backwards and forwards.他打开电灯并开始走来走去。
• All the girls fell over backwards to get the party ready.姑娘们迫不及待地为聚会做准备。

11 anemia   

n.贫血，贫血症

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。
• I was put on iron tablets for my anemia.我曾因贫血吃补铁药片。

12 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

13 fermented   

v.（使）发酵( ferment的过去式和过去分词 )；（使）激动；骚动；骚扰

参考例句：

• When wine is fermented, it gives off gas. 酒发酵时发出气泡。 来自《简明英汉词典》
• His speeches fermented trouble among the workers. 他的演讲在工人中引起骚动。 来自辞典例句

14 vessels   

n.血管( vessel的名词复数 )；船；容器；（具有特殊品质或接受特殊品质的）人

参考例句：

• The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
• All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》

15 calcium   

n.钙(化学符号Ca)

参考例句：

• We need calcium to make bones.我们需要钙来壮骨。
• Calcium is found most abundantly in milk.奶含钙最丰富。

16 cholesterol   

n.（U）胆固醇

参考例句：

• There is cholesterol in the cell of body.人体细胞里有胆固醇。
• They are determining the serum-protein and cholesterol levels.他们正在测定血清蛋白和胆固醇的浓度。

17 intestines   

n.肠( intestine的名词复数 )

参考例句：

• Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
• The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 来自辞典例句

18 spinach   

n.菠菜

参考例句：

• Eating spinach is supposed to make you strong.据说吃菠菜能使人强壮。
• You should eat such vegetables as carrot,celery and spinach.你应该吃胡萝卜、芹菜和菠菜这类的蔬菜。