We’re always being told by the Department of Health to eat five portions of

游客2024-09-22 40

问题 We’re always being told by the Department of Health to eat five portions of fruit and vegetables a day. But it’s not clear where the evidence for this comes from and a large study by the European Prospective Investigation into Cancer and Nutrition(EPIC)two years ago of the dietary intake of more than 400,000 people found only a weak link between eating fruit and vegetables and a reduction in overall cancer risk. There’s no evidence it reduces breast or prostate cancer.
Even so, how could anyone argue against eating more fruit and vegetables? Well, it depends what fruit you’re eating. A review article in the Canadian Medical Association Journal warns that a chemical in grapefruits can interact fatally with certain medicines. Even apple juice, the staple of many breakfast tables, may reduce our absorption of some drugs. Parents also often think fruit juice is a healthy alternative to soda drinks but juices contain sugar and calories too—as much as a glass of Coke(160 calories)—so should be drunk in moderation.
Grapefruit has also been linked to an increase in breast cancer. A study in the British Journal of Cancer(BJC)of 500,000 postmenopausal women found that eating a quarter of the fruit a day increased the risk by 30%.
There is one good reason for not eating grapefruits—they taste sour. But they are unlikely to increase your risk of breast cancer: further research in the BJC showed no increase of breast cancer in pre- or post-menopausal women who tuck into grapefruits or drink juice.
Grapefruit contains a type of chemical called furanocoumarin(also found in Seville oranges and limes but not Valencia or other sweet oranges), which, by inhibiting the enzyme CYP3A4, stops the breakdown of some prescription drugs. So the concentrations of these drugs rise and can have serious side-effects, including kidney damage, heart block(where no electrical impulses pass through the heart and it can stop beating), and deep vein thrombosis(which occurred when an oral contraceptive was taken by a woman who also ate grapefruit three days in a row).
Patient information leaflets should tell you what foods to avoid with which drugs. If in doubt, ask your doctor. So you don’t need to eat less fruit, and may still need to eat more. Another paper from the EPIC study found a 22% reduction in deaths from heart attacks in people who ate eight portions of fruit and vegetables a day compared to those who ate three or fewer. The way the study is designed, however, means that it can only suggest a link—it can’t prove one. [br] The result of the further study in the BJC was that______.

选项 A、eating fruit could reduce breast or prostate cancer risk
B、eating one fourth of grapefruit each day increased breast cancer risk
C、eating grapefruit didn’t increase breast cancer risk
D、eating more fruit reduced the death rate from heart attack

答案 C

解析细节题。由关键词the further study in the BJC定位到第四段最后一句，该句提到《英国癌症杂志》的进一步研究表明绝经前或绝经后的妇女猛吃西柚或大量喝果汁，其乳腺癌发病率并未增加，所以[C]“吃西柚没有增加乳腺癌的发病率”为正确答案。第一段最后一句提到，EPIC的研究没有证明吃水果和蔬菜能减少乳腺或前列腺的癌变，所以[A]“吃水果能够减少乳腺或前列腺的癌变”没有被证实，而且并非BJC所做的研究，故排除；[B]“每天吃四分之一的西柚增加乳腺癌的发病率”在第三段最后一句中被提及，但这是BJC以前的研究成果，并非进一步的研究成果，因此排除；最后一段第四句表明，由EPIC研究得出的另一篇论文发现，每天吃八份水果和蔬菜的人与那些每天吃三或四份的人相比，心脏病的死亡几率降低了22％，所以[D]“吃更多的水果降低了心脏病的死亡几率”是EPIC的研究结果，故排除。

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