Many factors have been suggested to reduce the risk of developing Alzheimer's disease, from consuming certain foods in our diet to increasing the amount of exercise we get, and even the extent to which we use our brains. But the evidence right now is not reliable enough to say that any of these modifiable factors actually influence our risk of Alzheimer's, according to a report published online today (May 9.)

The report summarizes the findings of a National Institutes of Health State-of-the-Science Conference that was held in April 2010 specifically to examine risk factors and possible preventative measures for Alzheimer's.

The only factors we can say with certainty affect a person's risk of Alzheimer's, according to the report, are things that are out of our control: age and genes. Most people who get Alzheimer's are over age 65. And people who have two copies of a gene called APOE-e4 have about a tenfold greater risk of developing Alzheimer's compared with someone without this gene.

So does this mean there's nothing you can do to prevent Alzheimer's? Not exactly. There could well be ways to prevent Alzheimer's that are within our control, the researchers say. But more rigorous, long-term studies need to be done to solidify the link between these factors and Alzheimer's disease risk.

Others argue the report tends to lump all risk factors together, when in fact, some factors are more well-supported than others.

"It fails to point out that we have a fair amount of evidence that suggests some potential risk factors for Alzheimer's disease," said William Thies, chief medical and scientific officer at the Alzheimer's Association. "And we shouldn't ignore those suggestions."

There is a pretty strong body of evidence to support the idea that physical activity lowers the risk of Alzheimer's disease , Thies, who wasn't involved in the report, said. On the other hand, there's very little data to back up the notion that enhancing cognition , through activates such as word puzzles, reduces the risk of Alzheimer's, he added.

At the end of the day, while none of these factors have been proven to reduce the risk of Alzheimer's, practicing them may not be such a bad idea since a few of them have been found to reduce the risk of chronic disease in general.

"There are some things that people can do that will certainly improve their health and may lower their risks of developing Alzheimer's disease," Thies told MyHealthNewsDaily.

These include exercising , keeping your weight under control, avoiding tobacco and excessive alcohol use and staying connected with friends, according to the Alzheimer's Association.

Conducting more studies to tease out the link between Alzheimer's disease and modifiable risks factors is ideal, but expensive, Thies said. More funding is needed to do these studies, he added.

"Until the federal government lives up to their responsibly to the public and begins to invest in Alzheimer's disease at a level that they should, we're not going to be able to do these studies," Thies said.

Pass it on: Genes and age are the only known risk factors for Alzheimer's disease. More research is needed to learn whether factors such as diet and exercise also influence Alzheimer's risk.

Follow MyHealthNewsDaily staff writer Rachael Rettner on Twitter @RachaelRettner.