单选题

Scientists have found that eating dark chocolate appears to lower the risk of depression by four fold.While 7.6 percent of the 13,000 people surveyed reported depressive symptoms, just 1.5 per-cent of the chocolate eaters did.

The study by University College London (UCL), the University of Calgary and Alberta Health Services Canada, also found that the people who consumed the most of any chocolate were also 57 percent less likely to report depressive symptoms.

Lead author Dr.Sarah Jackson, of UCL's Institute of Epidemiology & Health Care, said: “This study provides some evidence that consumption of chocolate, particularly dark chocolate, may be as-sociated with reduced odds of clinically relevant depressive symptoms.”

“Should a causal relation-ship demonstrating a protective effect of chocolate consumption on depressive symptoms be estab-lished, the biological mechanism needs to be understood to determine the type and amount ofchoco-late consumption for optimal depression prevention and management,” said Jackson. 

The study is the first to examine the association with depression according to the type of choco-late consumed.The team assessed data from 13,626 adults from the US National Health and Nutri-tion Examination Survey.A range of other factors including height, weight, marital status, ethnicity,education, household income, physical activity, smoking and chronic health problems were also tak-en into account to ensure the study only measured chocolate's effect on depressive symptoms. 

After adjusting for these factors, it was found that individuals who reported eating any dark chocolate in tw0 24-hour periods had 70 percent lower odds of reporting clinically relevant depres-sive symptoms in the previous two weeks than those who reported not eating chocolate at all. 

Most recent figures show that around 19.7 percent of people in Britain aged 16 and over showed symptoms of anxiety or depression.Chocolate contains a number of psychoactive ingredi-ents which produce a feeling of euphoria similar to that of cannabinoid, found in cannabis.It also contains phenylethylamine, a neuromodulator which is believed to be important for regulating peo-ple's moods.Dark chocolate also has a higher concentration of flavonoids, antioxidant chemicals which lower inflammation and can prevent the onset of depression. 

However British scientists urged caution about the findings, suggesting that the decision to eat dark chocolate could be linked to other health factors.For example people who choose dark choco-late may be more health conscious in general, which is known to protect against depression. 

Depressed people are also more likely to crave more sugary fatty foods and so could be less likely to pick a dark altemative when choosing chocolate.

According to Dr.Sarah Jackson, which of the following statements is true?无
【正确答案】 D
【答案解析】细节题。根据题干关键词Dr.Sarah Jackson可定位到原文第三段。A项“只有食用黑巧克力才能降低患抑郁症的概率”与第一句“这项研究提供了一些证据以证明吃巧克力——尤其是黑巧克力——可能与降低临床相关抑郁症状的概率有关”不符,故错误。Jackson并没有明确表明吃巧克力与预防抑郁症之间的因果关系,而是用省略if的条件句,表假设,故B项“吃巧克力与预防抑郁症之间的因果关系已建立”错误。他们的研究并没有发现食用哪种巧克力以及需食用多少能够预防抑郁症,故C项“他们的研究已经确定预防和治疗抑郁症所需食用巧克力的种类和数量”错误。D项“要确定预防和治疗抑郁症所需食用巧克力的种类和数量需要了解生物机制”是原文the biological mechanism needs to be understood…and management的同义改写。故本题选D。