There’s no strong evidence that anything prevents Alzheimer’s disease, but a few common-sense practices may help delay memory loss, a panel of experts said Thursday.

They include controlling high blood pressure, regular exercise and specific memory training exercises.

Illustration of the thought processes in the brain Getty Images/iStockphoto

Outside of that, there’s no miracle cure and no surefire way to delay the loss of brain power that comes with aging, or the onset of dementia, the committee at the National Academies of Sciences, Engineering and Medicine concluded.

More than 5 million Americans have Alzheimer’s, and this number is expected to grow as the population ages. There’s no cure, and treatments do not work well. Drugs such as Aricept, known also as donezepil, and Namenda can reduce symptoms for a time but they do not slow the worsening of the disease.

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Researchers have some hints that drugs can reduce the brain-clogging plaques that are a hallmark of Alzheimer’s but they have not shown conclusively that the drugs can help symptoms or prevent disease. Such drugs are also years away from getting on the market.

“The strongest evidence was in the area of cognitive training."

But there is evidence that some lifestyle changes might reduce the risk, or at least delay the onset of dementia.

The committee of experts looked at all the best research on ways to prevent memory loss and what’s called cognitive impairment — the loss of the ability to think clearly and make decisions.

Despite the explosion of online and commercial products — from supplements to memory games — that allege they can help, there’s very little out there that can be proven to slow or prevent the decline, the experts reluctantly concluded.

“At present, there are no pharmacologic or lifestyle interventions that will prevent mild cognitive impairment or Alzheimer's disease,” said Dr. Ronald Petersen, an Alzheimer’s expert at the Mayo Clinic, who was on the committee.

“All this is not new, but this review is the strongest evidence base we have,” Petersen added.

“We have all been exposed to a study here, a study there. One suggests this intervention is beneficial, the other finds it’s not. This review looked at the totality of literature over last six years and put it to the most rigorous test you can imagine.”

There are three rays of hope: cognitive training, blood pressure control and exercise.

“Even though clinical trials have not conclusively supported the three interventions discussed in our report, the evidence is strong enough to suggest the public should at least have access to these results to help inform their decisions about how they can invest their time and resources to maintain brain health with aging,” said Dr. Alan Leshner, chair of the committee and CEO emeritus of the American Association for the Advancement of Science.

“The strongest evidence was in the area of cognitive training,” Petersen said.

This doesn’t mean crossword puzzles or Sudoku, although those won’t hurt, Petersen cautioned. The best evidence came from a study looking at specialized training.

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“This was a study that looked at specific training of groups of people on, for example, memory improvement techniques, mnemonic techniques as they're called,” Petersen told NBC News.

“How can I improve my memory? Can I organize material that will help me remember material at a later point in time? Can I use certain strategies that will help me process information more quickly and more efficiently that may benefit me later on down the road?”

People will have to work at it, Petersen said. “Can you, in fact, find a new way to try to remember a list of grocery items?” Peterson asked. Instead of using a smartphone calculator to figure out a tip, do it in your head, he advised.

Commercial products have not proven they help, Petersen cautioned.

“We’re very concerned about the brain game industry taking this and running with it, and say NAS has shown that cognitive training is going to forestall cognitive decline, and we have our brain game here,” he said.

Most have done little more than show they make people better at playing those particular games, Petersen noted.

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Controlling blood pressure is something people should do anyway, to prevent heart disease. But good evidence shows it can reduce the risk of memory loss and dementia, probably because high blood pressure damages delicate blood vessels in the brain.

And several studies have shown that exercise can help.

“Here we're talking about modest aerobic exercise,” Petersen said. That includes brisk walking.

“How much? Maybe 150 minutes a week — 30 minutes five times, 50 minutes three times — can have an effect on reducing cognitive impairment later in life,” Petersen said.

“Try to avoid the tendency to sit down, watch television for endless hours at night. Get out there, do something."

“Is it going to prevent Alzheimer's disease? I can't say that. But I think it may have an effect on reducing cognitive impairment.”

None of the evidence is strong enough to justify a public education campaign, the committee of experts concluded.

“We’re all urgently seeking ways to prevent dementia and cognitive decline with age,” said Dr. Richard Hodes, director of the National Institute on Aging.

“But we must consider the strength of evidence — or lack thereof — in making decisions about personal and public investments in prevention.”

Peterson said people can make everyday changes in their lives to keep their brains clearer.

“Try to avoid the tendency to sit down, watch television for endless hours at night. Get out there, do something,” he advised.

There’s no cure for Alzheimer’s and no long-term medical treatment that has been shown to reduce symptoms. But people who think they have symptoms should see a doctor as soon as possible, the Centers for Disease Control and Prevention says. People need to plan their futures, and some conditions, such as vitamin deficiency, look like dementia but are easily corrected.