Oct. 15, 2009 (Baltimore) -- A diet rich in cruciferous and green leafy vegetables, nuts, fish, and tomatoes and low in red meat and high-fat dairy products may protect against Alzheimer's disease, a study suggests.
Researcher Nikolaos Scarmeas, MD, associate professor of neurology at Columbia University in New York, tells WebMD that recommendations can't be made on this study alone. "But in general, these foods are part of what we consider a healthy diet for other reasons, such as protection against heart disease. And they could help [your brain]."
The study was presented at the annual meeting of the American Neurological Association (ANA).
The research involved 1,691 people aged 65 and older with no signs of dementia when they entered the study. All filled out detailed questionnaires that asked about what foods they ate over the past year.
The researchers then studied various foods in the lab to determine which were rich in nutrients such as omega-3 fatty acids and vitamin E that have been linked to a lower risk of Alzheimer's disease and which were low in nutrients such as saturated fatty acids that have been linked to a greater risk.
Based on the amounts of each nutrient in each food, "we discovered an Alzheimer's-disease-protective dietary pattern that was characterized by a high consumption of nuts, fish, salad dressing, poultry, tomatoes, cruciferous, dark, and green leafy vegetables and fruits, and low in high-fat dairy, red meat, organ meat, and butter," Scarmeas says. "Foods are not consumed in isolation, so studying the dietary pattern may offer substantial advantage."
The 1,691 study participants were then divided into three groups according to how well they adhered to such a diet over the past year. Over the next four years, 211 of them were diagnosed with Alzheimer's disease. Results showed that those in the top third were 38% less likely to develop Alzheimer's four years later than those in the lowest third.
The analysis was adjusted for a variety of factors that could potentially explain the association, including age, smoking status, physical activity, body mass index, and caloric intake.
The fact that the researchers followed healthy people over time and that the analysis was adjusted to take into account factors such as physical activity that may also lower the risk of Alzheimer's disease gives it strength, says Craig Blackstone, MD, PhD, of the National Institute of Neurological Disorders and Stroke.
"This is certainly a healthy diet to follow," he says.