衛生類：閱讀理解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.

　　練習：

　　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.

　　答案與題解：

　　1.C 短文開頭第一句就說，“吃土豆有益于腸道健康，而且對整個免疫系統也有益，尤其是吃土豆色拉或涼吃”，因此在四個選項中最有營養的非C項莫屬。

　　2.A 第二段第三句說，“淋巴細胞水平低顯示炎癥水平下降”，故其他B、C、D三個選項均不正確。

　　3.B 第二段第二句引用了研究組負責人自己的話說，“在實驗中使用未經加丁的土豆淀粉，就是為了模擬富含耐久淀粉的飲食所起的作用”，其他A、C、D三個選項文章均沒有提及。

　　4.D 第四段第一句列出了一些富含耐久淀粉的食品，其中就沒有D項“蔬菜”，而且實際上蔬菜也不是富含淀粉的食物。

　　5.D 第四段倒數第二句已經解釋了耐久淀粉的特點：“不能在小腸中消化，而是分流到大腸，在大腸中發酵”。其他選項個別詞語雖在短文中出現過，但都不是說明耐久淀粉的。