A healthy diet is one of the first steps to promote your Cognitive Vitality. But with so many fad diets, it can be tough to understand which are the most likely to improve brain health. Three diets—the Mediterranean Diet, the Dietary Approaches to Stop Hypertension (DASH) diet, and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet—have enough evidence for us to evaluate their potential benefits.
The Mediterranean diet is inspired by the dietary habits of Greece, Southern Italy, and Spain. It emphasizes food high in monounsaturated fatty acids found in olive oil, omega-3 fatty acids found in fish and nuts, and fresh fruits and vegetables. To date, the Mediterranean diet has been the most extensively researched with strong data to suggest that it can help to protect against cardiovascular disease, diabetes, and cancer and even promote longevity. Some epidemiology also suggests long-term benefits for cognitive health, including reduced risks of Alzheimer’s disease and cognitive impairment, possibly through mechanisms that reduce inflammation and oxidative stress. In a randomized clinical trial, the Mediterranean diet was compared to a control low-fat diet and appeared to promote cognitive function in older adults at risk of cardiovascular disease. Additional information on the Mediterranean diet can be found at University of Wisconsin (PDF) and Mayo Clinic.
The DASH Diet was developed by the National Institutes of Health to prevent and control hypertension without medication. It emphasizes high consumption of fruits, vegetables, low-fat dairy, whole grains, lean meats, nuts, and beans and was reported to significantly reduce blood pressure in those with moderate hypertension. Hypertension can deteriorate blood vessels in the brain and is a risk factor for Alzheimer’s, thus lowering blood pressure with the DASH diet may also protect the brain. The DASH diet is only beginning to be tested for neuroprotection, but the results are promising: higher adherence to the DASH diet in 800 elderly subjects from the Memory and Aging Project was associated with significantly slower rates of cognitive decline. Additional information on the DASH diet can be found at National Heart, Lung and Blood Institute, Mayo Clinic, and American Heart Association.
The MIND diet was introduced in 2015 by Dr. Martha Clare Morris, a leading expert in nutritional epidemiology at Rush University Medical Center. She searched through the scientific literature, primarily from observational studies, to put together what she considers the best foods for brain health from the DASH and Mediterranean diets. The diet emphasizes green leafy vegetables (rather than all vegetables), berries (rather than all fruit), nuts, beans, whole grains, fish, poultry, olive oil, and moderate amounts of alcohol (preferably red wine). It suggests avoiding red meat, butter, cheese, pastries, sweets, and fried food (WebMD). So far, this new diet has only been tested in the scientific literature by Dr. Morris. Her studies have compared the Mediterranean, DASH, and MIND diets in individuals aged 58–98 years. The research found that high scores in all three diets were associated with a reduced risk of Alzheimer’s disease, but the MIND diet was the only diet in which even moderate adherence was beneficial. The MIND diet was also associated with a slower decline in global cognition, the equivalent of being 7.5 years younger in age cognitively. However, all of these studies are still observational, making it very difficult to confirm whether the benefits are caused by the diet or by other characteristics shared by the people who choose these foods. Additional information on the MIND diet can be found at WebMD, and Rush University.
More research could help determine which of these diets has the most potential benefit for brain health. In the meantime, take note of the basic characteristics that they share: high levels of fruits, vegetables, fish, and legumes and low levels of processed foods, red meat, sweets, and sugars.
Nick McKeehan is a member of the ADDF's Aging and Alzheimer's Prevention program. He evaluates the scientific evidence for and against therapies to promote brain health and/or prevent Alzheimer's disease at our website CognitiveVitality.org and contributes regularly to the site's blog. Mr. McKeehan previously served as Chief Intern at Mid Atlantic Bio Angels (MABA) and was a research technician at Albert Einstein College of Medicine investigating repair capabilities of the brain. Mr. McKeehan received a bachelor of science degree in biology from Purdue University, where he was awarded a Howard Hughes Scholarship. He also writes about the biotechnology industry for 1st Pitch Life Science.
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