卫生类：阅读理解Eating Potatoes Gives
Eating potatoes is not only good for bowel health， but also for the whole immune system， especially when they come in the form of a potato salad or eaten cold. In a study on an animal model， researchers in Spain found that pigs fed large quantities of raw potato starch (RPS) 1 not only had a healthier bowel， but also decreased levels of white blood cells， such as leucocytes and lymphocytes in their blood. White blood cells are produced as a result of inflammation or disease， generally when the body is challenged.
The general down-regulation of leucocytes observed by the Spanish researchers suggests an overall beneficial effect， a generally more healthy body. 2 The reduction in leucocyte levels was about 15 percent. Lower lymphocyte levels are also indicative of reduced levels of inflammation， but the observed reduction in both lymphocyte density and lymphocyte apoptosis is surprising.
In what was the longest study of its kind， pigs were fed RPS over 14 weeks to find out the effect of starch on bowel health. “The use of raw potato starch in this experiment is designed to simulate the effects of a diet high in resistant starch，” said study leader Jose Francisco Perez at the Universitat Autonoma de Barcelona3， Spain.
Humans do not eat raw potatoes， but they do eat a lot of foods that contain resistant starch， such as cold boiled potatoes， legumes， grains， green bananas， pasta and cereals. About 10 percent of the starch eaten by human is resistant starch―starch that is not digested in the small intestine and so is shunted into the large intestine where it ferments. Starch consumption is thought to reduce the risk of large bowel cancer and may also have an effect on irritable bowel syndrome (IBS)4
Immunology expert Lena Ohman’s team previously found that the overall lymphocyte levels do not vary for IBS patients， but that lymphocytes are transferred from the peripheral blood to the gut， which support the hypothesis of IBS being at least partially an inflammatory disorder. She says the decrease in lymphocytes observed by the Spanish is therefore interesting， and a diet of resistant starch may be worth trying in IBS patients. Ohman is currently at the Department of Internal Medicine， Goteborg University， Sweden5. The study is published in the journal Chemistry and Industry， the magazine of the SCI6.
练习：
1. What form of potato is the most nutrient to the human body?
A Potato soup.
B Potato cake.
C Potato salad.
D Hot boiled potato.
2. What does the reduction in leucocyte levels in the body mean?
A It may mean the reduced levels of inflammation.
B It may mean somewhere in the body is inflamed.
C It means that the body is challenged.
D It means that the body cannot produce leucocytes any more.
3. For what a purpose did the researchers use raw potato starch in their experiment?
A They warned to observe how the leucocyte levels reduced in the experimental pigs.
B They wanted to simulate the effects of a diet high in resistant starch.
C They wanted to see how much potato an experimental pig ate every day.
D They wanted to see how much body weight each experimental pig gained in the end.
4. All of the following foods are rich in resistant starch EXCEPT
A pasta
B grains
C legumes
D vegetables
5. What a kind of starch is resistant starch after all?
A It may cause irritable bowel syndrome.
B It may bring about at least partially inflammatory disorder.
C It may raise leucocyte and lymphocyte levels in the body.
D It cannot be digested in the small intestine and ferments in the large intestine.
答案与题解：
1.C 短文开头第一句就说，“吃土豆有益于肠道健康，而且对整个免疫系统也有益，尤其是吃土豆色拉或凉吃”，因此在四个选项中最有营养的非C项莫属。
2.A 第二段第三句说，“淋巴细胞水平低显示炎症水平下降”，故其他B、C、D三个选项均不正确。
3.B 第二段第二句引用了研究组负责人自己的话说，“在实验中使用未经加丁的土豆淀粉，就是为了模拟富含耐久淀粉的饮食所起的作用”，其他A、C、D三个选项文章均没有提及。
4.D 第四段第一句列出了一些富含耐久淀粉的食品，其中就没有D项“蔬菜”，而且实际上蔬菜也不是富含淀粉的食物。
5.D 第四段倒数第二句已经解释了耐久淀粉的特点：“不能在小肠中消化，而是分流到大肠，在大肠中发酵”。其他选项个别词语虽在短文中出现过，但都不是说明耐久淀粉的。