問題詳情
Discourse Organization
We’re told that tea and coffee dehydrates us, says Claudia Hammond, but what’s theevidence say? 16. They enjoy the taste and the fact that the caffeine wakes them up. But whenwe’re exhorted to drink six or eight glasses of water a day (a disputed figure that I’ve discussedpreviously), it’s usually emphasized that drinks like coffee and tea don’t count towards your dailyliquid total because they’re dehydrating. Or so we’re told. What’s the evidence? Although tea and coffee contain many different substances the one on which most researchfocuses is caffeine. Even then there is so little research on the topic, that one of the mostfrequently mentioned studies was conducted way back in 1928 with a sample of just three people.The three men were studied over the course of two winters. Sometimes they were required todrink four cups of coffee a day; sometimes they drank mainly tea and at other times theyabstained or drank water laced with pure caffeine. 17 .The authors concluded that if themen consumed caffeine-laced water after a two month period of abstinence from both coffee andtea, the volume of their urine increased by 50%, but when they drank coffee regularly again theybecame inured to its diuretic effects. Very large doses of caffeine are known to increase the blood flow to the kidneys and toinhibit the absorption of sodium which explains why it could act as a diuretic, dealing with thesodium which hasn’t been absorbed. But the exact mechanism is still a matter of debate. 18. A review of 10 studies by Lawrence Armstrong from the University ofConnecticut concluded that caffeine is a mild diuretic at most, with 12 out of 15 comparisonsshowing that people urinated the same amount, regardless of whether the water they drankcontained added caffeine or not. So why do so many people think they need the loo more often when they’ve been drinkingtea or coffee? As the review indicates, most studies give people pure caffeine added to water,rather than cups of actual tea or coffee as you might drink at home. Is there something about thecombination of substances contained in coffee and tea that make the difference? In a rare study where people drank nothing but tea for the 12 hour duration of the trial, therewas no difference in hydration levels between them and the people who drank the same quantityof boiled water. 19. But these participants had abstained from caffeine before the study,so this doesn’t tell us what would happen in people who are accustomed to drinking coffee. A second study found no difference in hydration between those drinking water or coffee,leaving us with conflicting findings. Then came new research earlier this year from Sophie Killerat Birmingham University in the UK, who not only measured the volume of urine, but tested theirblood for signs of kidney function as well as calculating the total amount of water in the body.The men in the study drank four cups of coffee a day, far more than the average coffee-drinker.Yet there was no evidence they were any more dehydrated than those who drank water alone.This research was funded by the Institute for Scientific Information on Coffee, whose membersare coffee companies, but it has been published in a peer-reviewed journal and the authorsconfirm that the Institute played no role in gathering or analyzing the data or writing up theresearch. 20. If you chose a glass of water instead of a cup of tea, you’d probably see the sameeffect.Fromhttp://www.bbc.com/future/story/20140402-are-coffee-and-tea-dehydrating
【題組】16.
(A) Meanwhile the volume of their urine was measured regularly.
(B) When it comes to the consumption of coffee, one study did find a 41% increase in urine,along with a rise in the excretion of sodium and potassium.
(C) Every day people around the globe drink 1.6 billion cups of coffee and around twice as manycups of tea.
(D) So although we might notice needing the loo more when we’ve been drinking coffee, themistake is basing our observations on a comparison with the time we’ve drunk nothing, not witha similar amount of water.
(E) But when you look at the studies of more realistic quantities of caffeine, the diuretic effect isnot nearly so clear.
參考答案
答案：C
難度：簡單0.738095
統計：A(2),B(9),C(62),D(5),E(4)