托福阅读备考习题.docx

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【Introduction】

Doctors have long known that vitamin D is essential to good health. Get enough of it and it ensures strong bones and teeth. But a new study this week suggests an even more extraordinary benefit: a lower risk of death.

【Section One】Article

Vitamin D Lowers Risk of Death

The new paper, published in the Sept. 10 issue of the Archives of Internal Medicine, is a meta-analysis of 18 previously published studies on the vitamin. None of the original experiments was specifically designed to study how vitamin D affects mortality — the trials involved conditions such as bone fractures, bone mineral density, congestive heart failure and colorectal cancer — but all of them tracked participants‘ death data. Overall, researchers found, people who took daily vitamin D supplements were 7% less likely to die during the study — from any cause — than people who didn‘t.

The study‘s authors still don‘t know exactly how the vitamin may reduce people‘s death risk, but their findings are in line with a spate of recent research linking the vitamin to a wide range of health benefits. Not only does it promote calcium absorption and bone maintenance, but vitamin D also appears to stimulate the immune system, inhibit cellular proliferation a