Those and other findings were reported Sunday in Washington, D.C., at the first Alzheimer's Association International Conference on the Prevention of Dementia. They suggest that lifestyle is closely linked to the development of this disease, which causes confusion, memory loss and behavioral changes.

If lifestyle changes can prevent or slow the disease, people might get a diagnosis at age 75 instead of at 70, says Ronald Petersen of the Mayo Clinic Alzheimer's Disease Center in Rochester, Minn. In some cases, a delay could mean the disease never fully takes hold, he adds.

The race to prevent Alzheimer's has taken on an urgency as the number of Americans with the disease is expected to soar in the coming decades. If current rates hold, up to 16 million people will develop Alzheimer's by the middle of the century, according to the Alzheimer's Association.

Their care could push Medicare spending for the disease from about $91 billion in 2005 to more than $1 trillion by 2050, Petersen says.

"We've got to do something about this disease or it's going to bankrupt the system," he says.

Could something as simple as drinking juice help hold off Alzheimer's? Maybe.

Amy Borenstein of the University of South Florida College of Public Health studied more than 1,800 people and found that those who drank fruit or vegetable juice three times or more a week were four times less likely to develop Alzheimer's late in life than people who rarely or never drank juice.

Borenstein and her colleagues believe the protective power of juice comes from polyphenols, powerful antioxidants found in the skin and peel of fruits and vegetables. Polyphenols are concentrated in juice that is made by crushing the whole fruit, she says.

Five tips to keep your brain in shape Stay mentally active by taking classes, learning new skills or even playing games like bingo or chess. Maintain social ties by doing volunteer work, joining clubs, keeping up with friends and family. Get out and move by taking walks, riding a bike, gardening or doing anything that involves physical activity. Even housework counts. Eat a brain-healthy diet by picking low-fat foods, lots of whole grains, fruits and vegetables — including juices — and don't forget fish and nuts that contain beneficial omega-3 fatty acids. Keep your body weight in check — some studies have linked obesity to the development of Alzheimer's. Source: Elizabeth Edgerly, program director for the Alzheimer's Association Northern California/Northern Nevada chapter

The findings must be verified by additional studies. But Borenstein says her research suggests that drinking at least three 8-ounce glasses of juice each week might be beneficial.

Another prescription for a better brain: Work out. Take a walk. Ride a bike.

"In our study, almost any report of exercise seemed to be good for the brain," says Mark Sager, a researcher at the University of Wisconsin-Madison Medical School.

Sager and his colleagues studied nearly 500 men and women with an average age of 53. None had any sign of Alzheimer's, but tests revealed that people who reported regular exercise performed slightly better on memory tests.

Sager says the results fit with other research showing that exercise can boost the number of new brain-cell connections that provide a mental edge in midlife and might offer a hedge against Alzheimer's.

Sager's study found another habit that helped boost brainpower: Men and women who reported drinking one to three alcoholic drinks a week also did slightly better on such tests.

Other studies have suggested red wine, which also is rich in protective polyphenols, reduces the risk of developing the disease, he says.

Margaret Gatz of the University of Southern California reported that people with signs of gum disease, a bacterial infection of the mouth, have a greater risk of developing Alzheimer's. Her study of 109 pairs of identical twins adds to evidence that chronic inflammation caused by gum disease can lead to a number of health problems, including Alzheimer's. To sidestep this risk factor, brush and floss your teeth, Gatz advises.

Alzheimer's smolders in the brain for decades before erupting into full-fledged symptoms, usually after age 60, says William Thies of the Alzheimer's Association. Sager and others say it's best to develop brain-healthy habits as early as possible. "We're hoping that 55 is not too late," he says.