Recently, fish oils found in species like salmon, trout and tuna have been associated with a lower risk of heart disease and even Alzheimer" s. Fish oil has since skyrocketed to be the most popular supplement in the United States. But a new study in the Journal of the National Cancer Institute, however, shows that these fish fats may not be improving everyone"s health—in the trial, those with high concentrations of marine-derived omega-3s in their blood showed a 43% higher risk of developing prostate cancer than those with the lowest levels. The study measured omega-3 blood levels in the participating men, and did not include information on the volunteers" eating habits, so researchers could not differentiate between the effects of fatty acids from fish from those of supplements. However, the overwhelming majority of the participants did not take fish oil supplements. Based on the results, Brasky says that men with a family history of prostate cancer should discuss with their doctor whether fish oil supplements are safe for them, since these pills tend to contain concentrated doses of omega-3—supplements contain between 30% to 60% of a serving of fish oil, and if a fish supplement is taken everyday, that adds up to a lot of daily fish oil. Brasky also suggested that men cut down on their fatty fish intake, though not eliminate it entirely. Andrew Vickers, a statistician specializing in prostate cancer at Memorial Sloan-Kettering Cancer Center, agrees, saying that fish oil supplements may pose a relatively higher risk for prostate cancer than fish in the diet. "The problem comes when you take components of a diet and put it in a pill," Vickers says. While the omega-3 fatty acids may increase oxidative damage to prostate cells, for example, antioxidants, which might be part of an overall healthy diet that includes fish as well as fruits and vegetables, might counteract these effects. Brasky"s work isn"t the first to suggest that omega-3 fatty acids may have both positive and negative effects on the body. In a September 2012 article in the Journal of the American Medical Association, researchers found that omega-3 supplements were not associated with lower risks of stroke or cardiac death. Those results were confirmed by another study in the New England Journal of Medicine that showed omega-3 supplements did not reduce risk of dying from a heart event among a group of people at high risk of heart disease. Researchers involved in those studies, however, acknowledged that they were not able to account for the effect of other medications to treat heart problems, such as cholesterol-lowering drugs and blood pressure medications, in keeping death rates down. In the same way, more research will have to tease apart how other nutrients in a balanced diet—including antioxidants—work together to influence the effect of individual nutrients like omega-3 fatty acids.
单选题 The underlined word "skyrocket"(Line 2, Paragraph 1)is closest in meaning to______.
【正确答案】 A
【答案解析】解析:本题考查考生对生词意思的理解。Skyrocket是“sky”(天空)和“rocket”(火箭)两个单词组成,是突然急剧上升的意思,在文中出现在第一段的第二句。该段的第一句指出:最近,在鲑鱼、鳟鱼和金枪鱼等鱼类中提取的鱼油被用来和较低的心脏病发病率甚至老年痴呆症发病率联系在一起。紧接着,作者提到,于是鱼油补充剂______,成为了美国最受欢迎的营养补充品,可见,是指鱼油补充剂销量猛增。在四个选项中,只有[A]是急剧上升的意思,是正确答案。[B]和[C]是[A]的反义词,[D]也含有增多的意思,但是没有剧烈迅速增加的意思,因此也不正确。
单选题 According to paragraph 2, fish oil supplements might be dangerous for men with a family history of prostate cancer because______.
【正确答案】 C
【答案解析】解析:本题考查考生对第二段中有关该研究具体细节的理解。第一段最后指出最近的一项研究表明鱼油可能不仅与更低的心脏病发病率甚至老年痴呆症发病率没有关系,而且甚至可能是造成前列腺癌高风险的因素之一。接着第二段就讲述这个研究的对象以及结果,指出“根据研究结果,布拉斯基表示,有前列腺癌家族史的男性,应与他们的医生讨论鱼油补充剂对他们是否安全,因为这些药往往含有浓缩剂量的欧米伽-3——补充剂所含脂肪酸的量是鱼类食品的30%至60%,如果每天服用鱼油补充剂,则使每天鱼油的摄入量大为增加。”可见,之所以说鱼油补充剂对于有家族前列腺癌史的男人来说可能是危险的,是因为这些人如果每天服用,那么鱼油的摄入量会在体内积聚达到危险的剂量。因此[C]是正确选项。[A]是第三段针对为什么鱼油补充剂比直接食用鱼对于前列腺癌症风险更高所作出的部分解释,没有出现在第二段。[B]和[D]与题目所问无关,因此均不正确。
单选题 According to the passage, fish oil supplements may pose a relatively higher risk for______than fish in the diet.
【正确答案】 B
【答案解析】解析:本题考查考生对全文关于鱼油补充剂对人体可能造成的风险方面的理解。需要注意的是,题目问的是与“fish in the diet”(即日常饮食当中的鱼)相比,鱼油补充剂对哪种疾病存在更高的风险。关于这一比较的讨论出现在文中第三段,第三段一开始就说“斯隆一凯特林癌症中心前列腺癌专家、统计学家安得烈·卫科,同样认为,鱼油补充剂对前列腺癌的风险比食谱中的鱼相对较高。”接着给出了原因。因此[B]是正确选项。[A][C][D]都是文中提到的与鱼油相关的疾病,但是都是属于传统意义上认为鱼油对之有积极意义(促进低风险)的疾病,而文章中讲述的研究也只是证明鱼油与这些疾病的低风险并没有直接关系,更不是与日常饮食中的鱼相比得出的结论,因此均不正确。
单选题 The reason that fish oil supplements may pose a relatively higher health risk than fish in the diet is that______.
【正确答案】 D
【答案解析】解析:本题与第三题一样,都是考查考生对第三段中有关鱼油补充剂和日常饮食当中的鱼肉对于健康风险的理解,本题是上一题的引申。在上一题中我们已经知道,第三段一开始就说鱼油补充剂对前列腺癌的风险比食谱中的鱼相对较高,紧接着就解释了原因:“欧米伽一3脂肪酸可能会增加前列腺细胞氧化性损伤,而全面健康的饮食,例如鱼类、水果和蔬菜,其中所包含的抗氧化剂,可能会抵消这些影响。”因此,[D]是正确选项。[A]选项比较具有诱惑力,因为它也是鱼油补充剂比日常饮食中的鱼对健康风险更大的部分原因,但是是间接原因,它并不能从根本上解释为什么鱼油累积多了就会对健康造成更大风险,因此不是正确选项。[B][C]偏离主题,是无关选项,均不正确。
单选题 It can be inferred from the last paragraph that______.
【正确答案】 C
【答案解析】解析:本题考查考生对最后一段内容的理解。最后一段主要是对前三段内容的总结和补充。最后一段又引用了另外两个研究证明了前面的结论:欧米伽一3脂肪酸补充剂和低中风或心脏猝死风险没有直接联系,以及欧米伽一3脂肪酸补充剂并没有减少心脏病高危人群死于心脏病的风险,即[A][B]选项的内容,这两个论据是文中直接给出的,不需要进行infer(推测,推论),因此[A][B]不正确。接下来,作者进行了补充说明,指出该项研究无法统计其他治疗心脏病药物以及均衡饮食中的营养成分,包括抗氧化剂,共同作用产生的对欧米伽一3脂肪酸单一营养成分的影响。也就是说,可能存在其他药物或者均衡饮食中的其他营养成分减少了死于心脏病的风险,因此,[C]是正确答案。[D]是第一段最后一句关于这项研究的结果的描述,并非来自对最后一段内容的推论,也不正确。