11/02/2011 08:21 am ET | Updated Jan 02, 2012

7 Ways to Decrease Your Risk of Alzheimer's

Promising new research suggests that half of all cases of Alzheimer's disease could be prevented by adopting healthier lifestyles. An important study carried out by Barnes and Yaffe at the University of California, San Francisco supports the idea that the way we use our brain and care for our brain can dramatically reduce our risk of Alzheimer's disease. It is empowering to realize that the lifestyle choices we make on a daily basis may well determine our likelihood of developing Alzheimer's disease.

As a neurologist, I care for many patients with Alzheimer's disease. Often these patients are brought to their appointments by their children or loved ones who worry that they too will develop dementia. For years I have encouraged these family members to do everything they can to keep their brain healthy and reduce their risk of dementia. Similarly, I care for patients with memory problems due to strokes, traumatic brain injuries, multiple sclerosis and a variety of other neurologic conditions. For these patients, it is crucial that they too do everything they can to protect their brain. It is wonderful to have this well-researched study by Barnes and Yaffe to reinforce the potential effect that simple lifestyle modifications may have on our brain.

The study looked at seven potentially modifiable risk factors for Alzheimer's, including diabetes, midlife hypertension, midlife obesity, smoking, depression, cognitive inactivity/low educational attainment and physical inactivity. The review determined how strongly these risk factors were associated with Alzheimer's disease and the proportion of people worldwide and in the U.S. whose condition could be attributed to these factors. Of these, physical inactivity was the most significant potential risk factor for Alzheimer's disease in the U.S. and the third largest worldwide.

There are multiple ways physical inactivity negatively impacts our brain. Sedentary lifestyles are associated with diabetes, hypertension and obesity, which in and of themselves are also risk factors for dementia. We also know that each of these conditions (diabetes, hypertension and obesity) along with smoking cause atherosclerosis, which results in diminished blood flow to the brain. When blood flow to the brain is compromised, our neurons are deprived of an adequate supply of nutrients and oxygen, which are necessary to keep our brain functioning at its best.

In addition, when we don't exercise we are missing out on the brain-enhancing benefits of exercise. Exercise is one of the very best things you can do to keep your mind sharp. Physical activity increases blood flow to the brain, directly boosts brain function and has been shown to actually increase brain volume. It triggers the release of neurotrophins or nerve growth factors, which promote the formation of new connections between neurons and stimulates the creation of new brain cells. Numerous studies have documented that sedentary elderly people who begin exercise programs perform better cognitively and have healthier, more robust brains.

On a worldwide basis, cognitive inactivity or low educational attainment is potentially the most significant risk factor for Alzheimer's, according to this study. This finding lends support to our growing understanding that nourishing our brain intellectually makes it stronger and more resilient to dementia. From birth we begin to build our neural networks, a process that continues throughout our lives. By learning new things and challenging our brain mentally, we literally build up our brain's infrastructure. Education and mental stimulation throughout our lives are believed to lower our risk of Alzheimer's disease, by providing a surplus or reserve of neural circuits to tap into as we age.

While it is never too late to make brain-enhancing lifestyle changes, the earlier we start the better. Middle age is a particularly important time to think about your brain, as this and other studies show that midlife obesity and midlife hypertension are significant risk factors for Alzheimer's disease. Similarly, diabetes is another risk factor that commonly creeps up in middle age and can often be prevented altogether and/or controlled by diet and exercise. If you or a loved one has one of these medical conditions, I strongly recommend that you work closely with your doctor to make sure they are optimally managed.

This important research updates our knowledge on Alzheimer's disease prevention. It should be noted, however, that associations between these lifestyle and health factors and Alzheimer's does not mean that they definitively cause the disease. In order to prove causality, rigorous testing with randomized controlled trails (RCTs) need to be performed. Few RCT studies have looked at health behaviors and Alzheimer's prevention. When studying the effect of lifestyle choices on health, it is very difficult to use RTCs, which require randomization to a control or treatment group for an extended period of time. It is unlikely that these studies will be done in the near future.

Published in The Lancet by Barnes and Yaffe, this article elegantly reviews the available studies on Alzheimer's risk factors. Many of these are observational studies that show a strong association between modifiable lifestyle factors and Alzheimer's disease. Given that there currently is no cure for Alzheimer's and that all of these risk factors are within our control, it is prudent that we do everything we can to prevent this devastating disease. Why not start today? As you take a brisk walk or jog, know that you are protecting your most valuable asset -- your brain.

Have a Beautiful Brain Day!