At a conference in the U.S. on Alzheimer's disease on June 19, researchers said that they think brain scans and simple blood tests may offer the best ways to predict who has the highest risk of Alzheimer's disease.
The also said by drinking juice daily and having the occasional alcoholic drink, it may be possible to lower the risk of developing the disease.
Dr. Ron Peterson of the Mayo Clinic in Rochester, Minnesota, said there is increasing evidence that we can do something for ourselves in terms of preventing the disease, and it is important to act early, before symptoms such a memory loss begin.
It is estimated by the Alzheimer's Association that 4.5 million Americans have the incurable, fatal brain disease which begins with mild memory loss and confusion and progresses gradually to a complete inability to care for oneself.
Worldwide 25 million people are thought to have dementia, and that number is expected to rise as the population ages.
Dr. Marilyn Alberts of Johns Hopkins University, says there is a need to be able to identify people at high risk as early as possible.
Several studies presented at the conference offered the possibility of predicting risk years before the disease develops.
Lisa Mosconi and colleagues at the New York University School of Medicine used positron emission tomography, or PET, scans to look at the brains of 53 normal elderly people.
The group was closely monitored for as long as 24 years to see who developed Alzheimer's.
It was found that nine did develop Alzheimer's, while 19 developed mild cognitive impairment, which can worsen into Alzheimer's.
The PET scans detected reduced activity in an area of the brain called the hippocampus, which is known to be damaged in Alzheimer's.
Mosconi said that a 15- to 40-percent reduction in activity in the hippocampus, as measured by PET, predicted 85 percent of the Alzheimer's patients nine years in advance, and it predicted 71 percent of the cognitive-impairment cases.
Another team in London used a different brain scan called magnetic resonance spectroscopy.
Alison Godbolt of the Institute of Neurology in London, scanned the brains of people who have a genetic flaw that makes them almost 100 percent certain to develop Alzheimer's, as well as people without the mutation.
The test looked for two compounds - N-acetyl aspartate and myo-inositol and found their levels could predict which patients developed Alzheimer's.
Dr. Neil Graff-Radford of the Mayo Clinic in Jacksonville and colleagues found that blood levels of a protein called amyloid beta 42 plunged three to five years before a patient was diagnosed with Alzheimer's.
Graff-Radford said they think this is because the protein, which makes up the brain-clogging fibers associated with Alzheimer's, stays in the brain instead of circulating in the blood.
Some drug companies are already targeting the protein with a vaccine in the hope of preventing Alzheimer's, but to date, there is no cure, and drugs can only temporarily slow the progression of Alzheimer's.
Amy Borenstein of the University of South Florida and colleagues in a study of 1,800 people over 30 years found that Japanese-Americans who drank the most fruit and vegetable juice were four times less likely to develop Alzheimer's than similar people who drank little or none.
Mark Sager of the University of Wisconsin and colleagues, in another study recruited people whose parents had Alzheimer's and found one clear way to predict who would also get the disease, how much alcohol they drank.
They found that moderate drinkers had a lower risk of Alzheimer's than either non-drinkers or heavy drinkers.
The prevention conference was sponsored by the Alzheimer's Association.