Bad News for Chocolate Lovers: It May Not Help Your Eyesight
Researchers have sad news for chocolate lovers. They found that eating dark chocolate does not improve people's eyesight as had been thought.
An earlier report suggested that some aspects of eyesight improved within one or two hours of eating chocolate. The new study found no changes in vision or blood flow after volunteers ate about 20 grams of dark chocolate. Both studies, however, involved only a small number of test subjects.
With two similar-sized tests producing opposite results, "more research is needed," said the organizers of the latest study. The lead researcher was Jacob Siedlecki of Ludwig-Maximilians-University in Munich, Germany.
Additional testing with larger sample sizes would be needed to rule in or out possible long-term benefits," the researchers wrote. Their report appears in the medical publication JAMA Ophthalmology.
The reason for suspecting dark chocolate might help with vision is that the sweet treat has plenty of flavonoids, which are antioxidants.
Antioxidants are man-made or natural substances that may prevent or delay some forms of cell damage. Studies have shown that foods with high levels of antioxidants can reduce the risk of an age-related vision problem called macular degeneration.
To see if the earlier study on chocolate could be repeated, Siedlecki and his team found 22 healthy volunteers, ages 20 to 62, who had good eyesight.
The volunteers were asked to eat either a 20-gram piece of dark chocolate or a 7.5-gram piece of milk chocolate. The piece of dark chocolate contained 400 milligrams of flavanoids, while the milk chocolate had about 5 milligrams of flavanoids.
Volunteers' eyes were examined with a relatively new, high-tech scanner that shows blood vessels in detail. The volunteers were tested before they ate the chocolate and again two hours later.
Siedlecki's team was looking for signs that the chocolate had enlarged blood vessels in the eye. This means volunteers were getting better blood flow.
Volunteers were also given low-technology vision tests similar to the ones used in the earlier chocolate study.
A week after the test, the people who got dark chocolate the first time were given milk chocolate, and those who had milk chocolate the first time were given dark chocolate.
The researchers said they found no difference in either test when volunteers ate dark chocolate or milk chocolate.
Doctor Gareth Lema was a little sad to read the latest findings. "I like chocolate," he explained.
While the new study failed to show any health benefit to eating a single piece of chocolate, "that doesn't mean eating it over the long term isn't beneficial," said Lema. He works at the New York Eye and Ear Infirmary of Mount Sinai in New York City.
"Neither study really showed that if you eat a piece of chocolate, you'll have (great) vision," Lema added.
Doctor Jay Chhablani agreed.
"Someone has to do a long-term study comparing dark chocolate to milk chocolate," he said. Chhablani is an associate professor of ophthalmology at the University of Pittsburgh School of Medicine.
Both men know it will be easy to find volunteers.
I'm Susan Shand.
1.a piece of 一片；一块
I picked up a piece of wood and started carving.
2.milk chocolate 牛奶巧克力
This is a cheaper milk chocolate.
3.dark chocolate 黑巧克力
I found one made of dark chocolate that is spectacular.
4.similar to 与...类似
The accident was similar to one that happened in 1973.
5.While the new study failed to show any health benefit to eating a single piece of chocolate, "that doesn't mean eating it over the long term isn't beneficial," said Lema.
over the long term 长期来看
Over the long term, such measures may only make the underlying situation worse.
Our challenge is the need to tackle our deficits over the long term.
6.Studies have shown that foods with high levels of antioxidants can reduce the risk of an age-related vision problem called macular degeneration.
reduce the risk of 降低...风险
People should eat less fat to reduce the risk of heart disease.
People need it for basic survival, and to reduce the risk of infectious disease.
研究人员有个坏消息要告诉巧克力爱好者们 。他们发现，吃黑巧克力并不会像人们想象的那样改善视力 。
早前的一份报告显示，吃巧克力一到两个小时，视力的某些方面会得到改善 。这项新研究发现，志愿者在食用大约20克黑巧克力后，视力和血液流量没有变化 。然而，这两项研究都只涉及了一小部分受试者 。
这项最新研究的组织者表示，由于两项规模类似的测试出现了截然不同的结果，“仍需要进行更多的研究” 。该研究的首席研究员是德国慕尼黑路德维希-马克西米利安大学的雅各布·塞德莱基 。
研究人员写道，“需要利用更多样本继续进行测试，以归纳或者排除可能的长期收获” 。他们的报告发表在医学杂志《美国医学会眼科杂志》上 。
抗氧化剂是人造或天然物质，能够防止或延缓某些形式的细胞损伤 。研究表明，富含抗氧化剂的食物可降低老年性视力问题——黄斑变性的风险 。
他们要求志愿者食用20克的黑巧克力或7.5克的牛奶巧克力 。一块黑巧克力含有400毫克的黄烷醇，而牛奶巧克力含有大约5毫克的黄烷醇 。
志愿者的眼睛接受了一种相对较新的高科技扫描仪的检查，这种扫描仪能够详细地显示血管 。志愿者在吃巧克力前以及食用两小时后分别接受了测试 。
塞德莱基的团队正在寻找巧克力使眼睛血管扩张的迹象 。这种迹象意味着志愿者的血流量更佳 。
利马（Gareth Lema）博士读到最新的发现时有点失落 。“我喜欢吃巧克力，”他解释道 。
利马表示，虽然新研究并未显示食用一块巧克力对健康有任何益处，“但这并不意味着长期吃巧克力就毫无裨益” 。他任职于纽约市西奈山的纽约眼耳科医院 。
杰伊（Jay Chhablani）Jay Chhablani博士对此表示认可 。
他说，“必须有人来做比较黑巧克力和牛奶巧克力的长期研究” 。杰伊是匹兹堡大学医学院的眼科副教授 。