By David Liu, PHD

Thursday Sept 27, 2012 (foodconsumer.org) -- Dementia like Alzheimer's disease is on the rise. But a new study recently published in the Journals of Gerontology suggests that the disease can be prevented in many cases by simply engaging in regular physical exercise.

The study led by researchers at University of South Florida in Tampa, Florida and colleagues found those who actively engaged in regular physical exercise at mid-life had their risk of developing dementia reduced by more than 50 percent, compared with those who did not do exercise.

Ross Andel and colleagues found the association between physical exercise at mid-life and subsequent risk of dementia such as Alzheimer's in men and women enrolled in the HARMONY study.

Subjects included 264 cases of dementia (176 Alzheimer's disease cases) and 2870 controls without the disease, and also 90 twin pairs aged 31 years on average and discordant for dementia who were identified in the Swedish Twin Registry.

After adjustment for age, sex, education, die, smoking status, alcohol consumption, body mass index and angina, the case-control study showed light physical exercise was associated with 37 percent reduced risk for dementia including Alzheimer's disease, compared to those who hardly did any physical exercise.

And for those who engaged in regular physical exercise, the risk for dementia was reduced by 66 percent, compared to those who did not do any exercise.

By definition, light physical exercise included gardening and walking and regular exercise included sports.

A similar association was found between physical exercise and risk of Alzheimer's disease.    Alzheimer's disease is a major form of dementia, so it is not surprising that physical exercise cut risk of Alzheimer's disease.

In the co-twin control analyses, high levels of physical exercise were also correlated with 50 percent reduced risk of dementia.

The researchers concluded physical exercise at midlife may lower the risk of dementia in older adulthood, suggesting that people should take physical exercise as a preventative to reduce their risk of dementia like Alzheimer's disease.

Millions of Americans are believed to live with Alzheimer's disease.  Dementia has no cure and it will eventually lead to a person's disability to live a normal life.  The disease has a number of risk factors and a healthy diet should be part of a prevention strategy.