Summary: Following the Mediterranean diet may reduce your risk of Mild Cognitive Impairment and Alzheimer’s, and may increase the lifespan of people already diagnosed with Alzheimer’s.
Dr. Nikos Scarmeas, Assistant Professor of Clinical Neurology at the Taub Institute for Alzheimer’s and the Aging Brain at Columbia University, studies the connection between diet and Alzheimer’s. Now he’s extended his research to include the connection between diet and Mild Cognitive Impairment (MCI), and has co-authored an article in this month’s Archives of Neurology about that research.
The new article and much of his recent research centers around the Mediterranean diet, and the results are encouraging. In several large population studies, he and his colleagues have found:
People who closely follow the Mediterranean diet have a lower risk of developing MCI (28% lower than those who don’t follow the diet very closely over a 4.5 year study period)
People who closely follow the Mediterranean diet have a lower risk of developing Alzheimer’s (40% lower over the 4 year study period)
People already diagnosed with MCI who closely follow the Mediterranean diet have a lower risk of “conversion” to Alzheimer’s (48% lower risk over a 4.5 year study period)
The Mediterranean diet emphasizes food from plant sources, along with “good fats” such as olive oil, and moderate consumption of fish, poultry, dairy products and wine. So which of these dietary factors might reduce the risk of Mild Cognitive Impairment or Alzheimer’s? “We do not know exactly to what extent each one is important,” says Dr. Scarmeas, “and we don’t know to what extent this importance is modified (enhanced or decreased) by the presence of the other ones. Considering them all together bypasses this problem.”
There are other limitations to what we know about this diet and memory. There are no studies on the effect of the diet on the risk of vascular dementia, he says, and none on whether the diet can actually improve memory and thinking. In addition, It could be that some other factor such as exercise could be responsible for preventing MCI or Alzheimer’s in the population studied. However, Dr. Scarmeas and colleagues adjusted the results to control for total calorie intake and Body Mass Index, which they believe would cover a large part of any exercise effect.
“These studies are not clinical trials; they are only observational,” says Dr. Scarmeas. “Based on only a few studies, we cannot say that the diet is definitely useful for brain diseases. But since it is helpful for other conditions, it makes sense to follow it anyway.”
If you want to learn more about the Mediterranean diet, the web site of Oldways, a “food issues think tank” is a good place to start.