Currently, no medicines or other treatments are known to prevent Alzheimer’s disease, but scientists are studying many possibilities. These possibilities include lifestyle factors such as exercise and physical activity, a healthy diet, and mentally stimulating activities. 

In addition to lifestyle factors, scientists have found clues that some long-term health conditions, like heart disease, high blood pressure, and diabetes, are related to Alzheimer's disease. It’s possible that controlling these conditions will reduce the risk of developing Alzheimer’s.

Studies show that exercise and other types of physical activity are good for our hearts, waistlines, and ability to carry out everyday activities. Research suggests that exercise may also play a role in reducing risk for Alzheimer’s disease.

Animal studies show that exercise increases both the number of small blood vessels that supply blood to the brain and the number of connections between nerve cells in older rats and mice. In addition, researchers have found that exercise raises the level of a nerve growth factor (a protein key to brain health) in an area of the brain that is important to memory and learning. 

A number of studies suggest that eating certain foods may help keep the brain healthy—and that others can be harmful. A diet that includes lots of fruits, vegetables, and whole grains and is low in fat and added sugar can reduce the risk of heart disease and diabetes. Researchers are looking at whether a healthy diet also can help prevent Alzheimer’s. 

One study reported that people who ate a “Mediterranean diet” had a 28 percent lower risk of developing MCI (mild cognitive impairment) and a 48 percent lower risk of progressing from MCI to Alzheimer’s disease. (MCI often, but not always, leads to Alzheimer’s dementia.) A Mediterranean diet includes vegetables, legumes, fruits, cereals, fish, olive oil, and low amounts of saturated fats, dairy products, meat, and poultry.

Other research has looked at the effect on brain health of several different vitamins and dietary supplements. One area of research focuses on antioxidants, natural substances that appear to fight damage caused by molecules called free radicals. Other studies are looking at resveratrol, a compound found in red grapes and red wine, as well as vitamins and other substances found in food. 

Age-related diseases and conditions—such as vascular disease, high blood pressure, heart disease, and diabetes—may increase the risk of Alzheimer’s. Many studies are looking at whether this risk can be reduced by preventing or controlling these diseases and conditions.

For example, one clinical trial is looking at how lowering blood pressure to or below current recommended levels may affect cognitive decline and the development of MCI and Alzheimer’s disease. Participants are older adults with high systolic (upper number) blood pressure who have a history of heart disease or stroke, or are at risk for those conditions.

Diabetes is another disease that has been linked to Alzheimer’s. Past research suggests that abnormal insulin production contributes to Alzheimer’s-related brain changes. (Insulin is the hormone involved in diabetes.) Diabetes treatments have been tested in people with Alzheimer’s, but the results have not been conclusive.

Keeping the mind sharp—through social engagement or intellectual stimulation—is associated with a lower risk of Alzheimer’s disease. Activities like working, volunteering, reading, going to lectures, and playing computer and other games are being studied to see if they might help prevent Alzheimer’s.

One clinical trial is testing the impact of formal cognitive training, with and without physical exercise, in people with MCI to see if it can prevent or delay Alzheimer’s disease. Other trials are underway in healthy older adults to see if exercise and/or cognitive training (for example, a demanding video game) can delay or prevent age-related cognitive decline.