Alter, don't falter

Exercise and eating a Mediterranean diet cuts the risk of Alzheimer's disease.

Lots of exercise, combined with eating a diet rich in fish, fruits and vegetables, may lower a person’s chance of developing Alzheimer’s disease, a study by Columbia University Medical Center in New York found.

Those who adhered most closely to the Mediterranean diet and were the most physically active had about a 60 per cent lower risk of developing the disease compared with those who didn’t follow the diet or exercise. The study found the overall risk for getting Alzheimer’s was 9 per cent for those who combined the most exercise and healthiest eating compared with 21 per cent for the least.

The study builds on previous research that showed sticking to a Mediterranean diet rich in olive oil, red wine, fish and fresh produce lowers the odds of developing Alzheimer’s disease. The authors said this was the first research to look at the impact of a combination of Mediterranean diet with exercise.

“If people have followed healthy lifestyles, that can include not only just diet, we could presumably reduce the rate of late life dementia,” David Knopman, a professor of neurology at Mayo Clinic in Rochester, Minnesota, said in a telephone interview. “This is something that sends a message to people in midlife and in younger life. Following a healthy diet from the time that you’re an adult is important.”

About 5 million Americans ages 65 and older have Alzheimer’s and the number may triple by 2050, according to the Alzheimer’s Association. Public health officials have called for solutions to the growing population of older adults facing the risk of the disease.

“This study is important because it shows that people may be able to alter their risk of developing Alzheimer’s by modifying their lifestyle through diet and exercise,” said Nikolaos Scarmeas, the lead author of the study. “We know that some part of Alzheimer’s is related to genetic changes and as time goes on we discover more and more of these changes. But it is also possible that non-genetic changes, including lifestyle and behaviour, may also be affecting our brain health.”

More research is needed to understand the exact mechanisms that connect diet and exercise with the biological changes of Alzheimer’s disease, said Scarmeas.

Eating healthy foods may lower a person’s risk of cardiovascular disease factors such as diabetes, high blood pressure and stroke, all of which may play a role in developing Alzheimer’s disease. Exercising may protect nerve cells and enhance nerve cell repair, as well as reduce inflammation in the body.

The researchers included 1,880 elderly residents of New York City who didn’t have dementia at the start of the study. They were measured on how closely their eating habits matched the Mediterranean diet as well as their exercise level.

Someone with high adherence to the diet ate more fruits, vegetables, cereal and fish and less meat and dairy foods. The researchers defined high physical activity as about 1.3 hours a week of vigorous exercise like jogging or four hours a week of light exercise such as walking. Those in the study were followed for a median of about 5.4 years. During that time, 282 people developed Alzheimer’s disease.

The researchers found that those who were very physically active had about a 33 per cent reduced risk of Alzheimer’s compared with those who didn’t exercise at all. Those who adhered the most to a Mediterranean-style diet had a 40 per cent reduced risk of the disease compared with those who didn’t eat much healthy food. People who combined the healthiest eating habits with the most exercise reduced their risk even more.

“It seems advisable that we emphasise not only to patients, but to healthy individuals too, the importance of these lifestyle behaviours in affecting our overall health,” Scarmeas said in the statement.

A second study, which examined 1,410 people, found that those who followed the Mediterranean diet had fewer errors on a state mental examination. The performance though on three other tests wasn’t associated with sticking to a Mediterranean diet, according to the researchers from Bordeaux, France, who also worked with Scarmeas.

“The Mediterranean diet pattern probably does not fully explain the better health of persons who adhere to it, but it may contribute directly,” wrote the authors from Bordeaux, France. “A Mediterranean diet also may indirectly constitute an indicator of a complex set of favourable social and lifestyle factors that contribute to better health.”

The first study was funded by the National Institute on Aging.