The public has been whipsawed by good and bad news about vitamins, much of it from test-tube or animal studies and hyped manufacturer claims. Even when researchers compare people's diets and find that a vitamin seems to help, the benefit may not translate when that nutrient is obtained a different way, such as a pill.

"Antioxidants, which include vitamin C and vitamin E, have been shown as a group to have potential benefit," but have not been tested individually for a long enough time to know, said Howard Sesso of Harvard-affiliated Brigham and Women's Hospital in Boston.

The Physicians Health Study, which he helped lead, was designed to do that. It involved 14,641 male doctors, 50 or older, including 1,274 who had cancer when or before the study started in 1997. They were included so scientists could see whether the vitamins could prevent a second cancer.

Participants were put into four groups and given vitamin E, vitamin C, both, or dummy pills. The dose of E was 400 international units every other day; C was 500 milligrams daily.

After an average of eight years, there were 1,929 cases of cancer, including 1,013 cases of prostate cancer, which many had hoped vitamin E would prevent.

However, rates of prostate cancer and of total cancer were similar among all four groups.

The study was funded by the National Institutes of Health and several vitamin makers. Results were being reported Sunday at an American Association for Cancer Research conference in Washington.

"Well-conducted clinical trials such as this are rapidly closing the door on the hope that common vitamin supplements may protect against cancer," said Marji McCullough, nutrition chief at the American Cancer Society. "It's still possible that some benefit exists for subgroups that couldn't be measured, but the overall results are certainly discouraging.

"The American Cancer Society recommends getting these and other nutrients by eating a mostly plant-based diet with a variety of vegetables, fruits and whole grains. A bonus is that this type of diet helps to prevent obesity, which increases the risk of several cancers."

About 12 percent of Americans take supplements of C and E. The new study does not mean these vitamins have no value, just that they didn't prevent cancer in this group of doctors, who may be healthier than the general population, said Dr. Peter Shields, deputy director of Georgetown University's Lombardi Comprehensive Cancer Center.

The best bet, he said, is to do things that are known to prevent the disease - eat right, maintain a healthy weight, and exercise.

French President Nicolas Sarkozy is backing down from comments critical of a planned U.S. missile defense system in Europe.

At a summit with Russian President Dmitry Medvedev on Friday, Sarkozy said the missile shield plans are misguided and will not make Europe safer. Those comments had been the strongest to date by an American ally against the missile-defense plans - and undercut the rationale behind President George W. Bush's European security strategy.

But after Saturday's global financial summit with other world leaders, Sarkozy said: "Ultimately, it could be a complement against a missile threat coming from elsewhere, for example, Iran."

The plans for using sites in Poland and the Czech Republic have infuriated Russia despite the Bush administration's insistence that they are aimed at protecting Europe from Iran.

President-elect Barack Obama has not been explicit about his intentions on European missile defense, saying it would be prudent to "explore the possibility" but expressing some skepticism about the technical capability of U.S. missile defenses.

Moscow sees the defense plans as a Cold War-style project that could eliminate Russia's nuclear deterrent or spy on its military installations. Much of Western Europe is nervous about the idea of such major defensive weaponry stationed around the continent.

But Poland and the Czech Republic, where bad memories of Soviet domination run deep, hope Obama follows through on the plans.

Polish Prime Minister Donald Tusk said Saturday it wasn't Sarkozy's place to take a stand on missile defense.

Tusk said missile defense is a matter strictly between the U.S. and Poland, and doesn't involve France or any other "third parties."

"The president of France Nicolas Sarkozy expressed his view but it will have no influence on what will happen with the project," he was quoted by the Polish news agency PAP as telling reporters in Warsaw.

"On the issue of the shield, I don't expect either commentary or actions from third parties," Tusk said.

The Associated Press on Friday suspended the use of photos provided by the Defense Department after the Army distributed a digitally altered photo of the U.S. military's first female four-star general.

The image of Army Gen. Ann E. Dunwoody is the second Army-provided photo the AP has eliminated from its service in the last two months.

The AP said that adjusting photos and other imagery, even for aesthetic reasons, damages the credibility of the information distributed by the military to news organizations and the public.

"For us, there's a zero-tolerance policy of adding or subtracting actual content from an image," said Santiago Lyon, the AP's director of photography.

Lyon said the AP is developing procedures to protect against further occurrences and, once those steps are in place, it will consider lifting the ban. He said the AP is also discussing the problem with the military.

Col. Cathy Abbott, chief of the Army's media relations division, said the Dunwoody photo did not violate Army policy that prohibits the cropping or editing of a photo to misrepresent the facts or change the circumstances of an event. She did not know who changed the photo or which Army office released it, she said.

Dunwoody was promoted to full general on Friday at a Pentagon ceremony attended by Gen. George Casey, the Army chief of staff.

In the original photo, the general appears to be sitting at a desk with a credenza and bookshelf behind her. Three stars on her uniform identify her as a lieutenant general, her rank before Friday's promotion.

The altered photo, distributed by the Army and run on the AP's photo wire Thursday, shows Dunwoody in fatigues in front of an American flag. Her rank, affixed to the front of a soldier's tunic, is not visible.

"We're not misrepresenting her," Abbott said. "The image is still clearly Gen. Dunwoody."

In September, the AP banned use of a photo of Army Staff Sgt. Darris Dawson, who was killed in Iraq. Dawson's face and shoulders appeared to have been digitally altered.

Abbott said Dawson's unit did not have an official photo of him and wanted one that could be used for a memorial service.

"That photo was released to the public strictly by accident," she said. "We apologized for that."

Bob Owen, deputy director of photography at the San Antonio Express-News, was the first to notice the changes in the Dawson and Dunwoody photos, finding the earlier versions on the Internet.

Owen said he views all photos supplied by the Defense Department skeptically.

"Photo journalists lose their jobs over this," he said.