Memory Special Report
Food for Thought
When it comes to maintaining healthy brain function, eating a standard American diet is not the smartest choice. The good news is that dietary changes -- in particular, the adoption of a Mediterranean-style eating plan -- can help prevent the onset or slow the rate of cognitive decline. In other words, foods that are good for your body are also good for your brain.
The popular Mediterranean diet consists of foods traditionally consumed by people living along the coast of the Mediterranean Sea, characterized by:
- smaller portion sizes than a Western diet
- a focus on fresh rather than processed foods
- a high intake of plant-based foods such as vegetables, fruits, legumes, and whole grains
- moderate amounts of nuts, olive oil, and fish, which are high in healthy monounsaturated and omega-3 fats
- moderate consumption of wine, typically with meals
- regular consumption of skinless poultry and low-fat dairy in smaller portions
- infrequent consumption of meat, which is high in saturated fats, and sweets
A study published in the Annals of Neurology found that among 2,258 participants (average age 76), those who closely followed the Mediterranean diet had a 40% lower risk of Alzheimer's disease than those with the least adherence after four years. Partial observation of the Mediterranean diet proved to have benefits, too, reducing the risk by 15%.
The Mediterranean diet may also keep those who have mild cognitive impairment (MCI) from progressing to Alzheimer's disease. A study published in the Archives of Neurology found that among people with MCI, the risk of developing Alzheimer's over a four-year period was 48% lower for those who strictly adhered to a Mediterranean diet. Those who moderately adhered to the Mediterranean diet had a 45% lower risk.
If you already have Alzheimer's disease, you can benefit from the Mediterranean diet as well. In a study of 192 people with Alzheimer's, published in Neurology, those who closely followed the Mediterranean diet lived four years longer than those who followed the diet least closely. Moderate adherents lived about one year longer.
Why It Works -- One possible explanation for the relationship between the Mediterranean diet and reduced Alzheimer's risk is that people who eat this way also engage in other behaviors that lower their risk of cognitive decline. But when researchers in the three studies mentioned above controlled for some of these factors, such as body weight, calorie intake, and smoking, the association between the Mediterranean diet and brain function remained strong.
What's so special about the Mediterranean diet? Researchers generally attribute its health-promoting benefits to two factors: 1) a high intake of fruits and vegetables, and 2) higher-than-usual intakes of olive oil and fish.
Fruits and vegetables are rich in free radical-fighting antioxidants like vitamins A, C, and E, which can help prevent oxidative damage in the brain. Olive oil and fish are rich in monounsaturated fat and omega-3 fat, respectively, which can quench inflammation in the brain. Research shows that inflammation and oxidative damage from free radicals may play a role in the brain changes typical of Alzheimer's disease.
The heart-healthy aspects of the Mediterranean diet also may contribute to its ability to slow cognitive decline. The Mediterranean diet promotes healthy blood vessels, and that means improved blood flow to the brain and better cognitive function. By contrast, reduced blood flow through arteries clogged with atherosclerotic plaque can lead to changes in the brain that can impair memory and thinking.
Posted in Memory on July 12, 2010