October 24, 2006
More promising news on the diet front: A Mediterranean-style diet, rich in fruits, vegetables, whole grains, and heart-healthy fats, may be good for the brain. Those are the findings of a new study from Columbia University Medical Center in New York, where researchers looked at the eating habits of nearly 2,000 seniors. They found that those who ate plenty of fruits, vegetables, legumes, cereals, olive oil, fish; moderate amounts of wine; and little red meat or high-fat dairy products had a lower risk of getting Alzheimer's disease.
The new findings, published online in the Archives of Neurology, complement a study from the same research team earlier this year that found that a heart-healthy diet like those people traditionally eat in Italy, Greece, and other Mediterranean countries may help to stave off Alzheimer's disease. [See the article, "Mediterranean Diet Helps Ward Off Memory Loss."] Earlier studies have shown that a Mediterranean diet may cut the risk of heart disease, cancer, diabetes, and possibly other ills. Growing evidence suggests such a diet may help keep the brain young as well.
The researchers studied 1,984 seniors, average age 76, living in northern Manhattan, including 194 who already had Alzheimer's disease. When they looked at what these men and women ate during the previous year, they found that the closer they adhered to a Mediterranean-style diet, the less likely they were to have Alzheimer's. Those in the top third, who followed the heart-healthy diet most closely, were 68 percent less likely to get Alzheimer's than those whose diets were least like it. Those in the middle third had a 53 percent lower risk. The findings held true even when considering other risk factors for the illness, such as age and weight.
Doctors are not sure why a Mediterranean diet may be good for the brain. One possibility is that such a diet reduces a risk for blood vessel disease, which may contribute to the risk for Alzheimer's disease. However, when the doctors looked at blood vessel factors, they did not appear to play a defining role in the onset of dementia. The researchers propose that other factors may be important. Increasingly, inflammation is seen as playing a major role in heart health, and it may play a role in Alzheimer's as well. A Mediterranean diet helps cut down on inflammatory substances in the body.
Oxidative stress, in which cells are damaged by highly reactive oxygen molecules called "free radicals," may also play a role. Fruits, vegetables, and other foods are high in antioxidants that help fight oxidative damage. The Mediterranean diet, named for the traditional diet of the Greeks and others living along the Mediterranean Sea, has long been advocated as a heart-healthy diet to ward off heart attacks and strokes.
The main elements of the Mediterranean diet include:
*An abundance of plant foods, such as fruits, vegetables, cereals, nuts, and beans;
*Using "good" fats, such as olive or canola oil, rather than butter or lard, and limiting dairy products like high-fat cheese and milk;
*Eating moderate amounts of fish and poultry, rather than red meat; and
*Drinking a glass or two of red wine a day.
Many other factors besides diet, including the genes you inherit and advancing age, play an important role in who ultimately develops Alzheimer's. Still, the findings add to a growing body of evidence that a heart-healthy lifestyle, with plenty of exercise, a sound diet, not smoking, and keeping weight down, may help keep the brain young.
For more on ways to maintain your brain, visit www.ALZinfo.org.
Nikolaos Scarmeas, MD, Yaakov Stern, PhD, Richard Mayeux, MD, Jose A. Luchsinger, MD: "Mediterranean Diet, Alzheimer Disease, and Vascular Mediation." Archives of Neurology, online edition. 2006; 63:(doi:10.1001/archneur.63.12.noc60109).