Dementia Studies Find Diet, Exercise Matter

Two studies published in this week's Journal of the American Medical Association add to evidence that long-term lifestyle habits may reduce the risk of mental decline in old age.

The first study, a long-term look at 1,880 elderly people in New York City, found that a Mediterranean-type diet and physical activity each were linked to less risk for Alzheimer's disease. The Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center released the data as part of a larger research project on aging.

The second study, a shorter-term observation of 1,410 patients in France, found some correlation between a Mediterranean-type diet and slower cognitive damage.

Nikolaos Scarmeas, the author of the first study, grew up eating fish and vegetables in Athens, Greece. Now the neurologist suggests more people take up his mother's cooking. Marked by high consumption of foods such as vegetables, legumes and cereals, served with olive oil, in addition to moderate fish and alcohol intake, the traditional diet has long conferred better cardiovascular health.

Starting in 1992, researchers at Columbia University monitored elderly patients every 18 months for diet, exercise and mental health, in addition to a number of controls including age, sex and education. "This is one of the first studies to tease apart the independent contributions of diet and exercise for dementia prevention," says Ronald Petersen, director of the Alzheimer's Disease Research Center at the Mayo Clinic in Rochester, Minn., who was not involved in the research. "It suggests that aging need not be a passive process."

These studies are observational and not definitive, but they hint at what might reduce the chances of Alzheimer's or dementia. In the Columbia research, those who adhered most closely to the diet reduced their risk for Alzheimer's by 40%, while those with the highest physical activity decreased their risk 33%, compared with people who didn't adhere closely to the diet or were not physically active.

The French study found that subjects who adhered to the Mediterranean-type diet experienced a slower rate of mental decline than those who did not eat the diet, but did not prove a link for dementia, which requires a clinical assessment of a variety of mental and social functions.

Doctors in the field are careful to note that none of these findings demonstrate a causal relationship, but instead reflect the advantages of a continual healthy lifestyle. "The benefits don't just occur at age 70 when you suddenly stop eating McDonald's and start eating Brussels sprouts," says David Knopman, a neurologist at the Mayo Clinic in Rochester, Minn., who wrote the editorial accompanying the studies in JAMA and wasn't involved in either study. His editorial highlights confounding variables in the studies. "Healthy diet and exercise is part of a package of lifelong healthy living."

Zaven Khachaturian, a senior science adviser to the Alzheimer's Association, agrees. "This offers interesting insight but we need to turn it now into clinical trials," says the former director of the Office of Alzheimer's Disease Research at the National Institutes of Health.

These findings arrive a few weeks after new research identified a gene that could help predict who will develop Alzheimer's—the leading cause of dementia—and at what age. The report, given in mid-July at the International Conference on Alzheimer's Disease, concentrated on DNA surrounding the ApoE gene. Researchers say more studies are needed before the findings can be confirmed.

For now, Dr. Scarmeas says his studies strongly suggest that a Mediterranean diet and exercise both confer independent and positive health benefits. But together, they are even better.

"The relative risk reduction for Alzheimer's is about 60% when you combine the diet and exercise," he says.

By CARRIE PORTER, The Wall Street Journal
Reviewed / Posted by: Scott W. Yates, MD, MBA, MS, FACP

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