综合一区欧美国产,99国产麻豆免费精品,九九精品黄色录像,亚洲激情青青草,久久亚洲熟妇熟,中文字幕av在线播放,国产一区二区卡,九九久久国产精品,久久精品视频免费

Preliminary studies suggested antioxidants might block the heart-damaging effects of oxygen on arteries and the cell damage that might encourage some kinds of cancer.

But some researchers now believe antioxidants work only when they are in food, or that people who eat vitamin-rich food are healthier simply because they take better care of themselves. And beta carotene supplements have been found to increase lung cancer risk in smokers.

Meir Stampfer, professor of nutrition and epidemiology at the Harvard School of Public Health, said the new analysis hasn't discouraged him from taking his vitamins.

Stampfer said the studies were too diverse to pool together because they looked at various combinations and doses of antioxidants tested in different groups of people. The trials ranged from a three-month study of 109 elderly nursing home residents to a 12-year study of 22,071 male doctors.

"This study does not advance our understanding, and could easily lead to misinterpretation of the data," said Stampfer, who was not connected to the new report.

The complaints were echoed by Andrew Shao, a scientist at the Council for Responsible Nutrition, a supplement trade association.

"Only when they included and excluded certain trials were they able to find this alleged increase in mortality, which they themselves can't explain," Shao said. "There is plenty of data out there that show regular use of antioxidant supplements help to maintain health."

Donald Berry, chairman of the department of biostatistics at the University of Texas M.D. Anderson Cancer Center, said the analysis persuades him antioxidants have no measurable health benefits, but he disagrees with the researchers' finding of an increase risk of dying.

"There are so many choices you can make when you're doing these analyses," he said.

Alice Lichtenstein, a professor of nutrition science and policy at Tufts University who was not involved with the research, said the study's main message is: "Rely on food to get your nutrients."

1

2