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Daily Dose

Want brain power? Doctor says to mind your diet.

Can what you eat actually affect how well your brain ages? That’s been a subject of heated debate as some scientists race to identify gene mutations linked to Alzheimer’s disease while others home in on nutrients that appear to protect against dementia and keep our brains sharp through the years.

Vegetarian activist Dr. Neal Barnard, a clinical researcher and adjunct professor at the George Washington University School of Medicine, believes the balance tips more toward diet than genes and advocates for a complete avoidance of animal products in his new book “Power Foods for the Brain.”

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Few nutritionists would argue with the basic tenets of Barnard’s eating plan: Consume a diet based on fruits, vegetables, legumes, nuts, and whole grains. He also urges regular exercise and adequate sleep to prevent brain diseases and rapid aging.

Where Barnard and his staff at the nonprofit Washington-based research group Physicians for Responsible Medicine part ways with the public health establishment is in their vegan approach to eating. In their view, meat, chicken, fish, dairy products, and most oils are not brain foods.

First off, animal products contain saturated fat, which “has been pretty strongly linked to Alzheimer’s risk,” Barnard says. “There’s no good reason to eat it.” Saturated fat raises artery-damaging cholesterol, and research suggests it contributes to the formation of beta amyloid plaques that gunk up the brain and are associated with Alzheimer’s disease.

That makes sense to me, but why should I avoid my fat-free Greek yogurt or egg white omelets that contain no saturated fat? Barnard has a weaker case to make against those because research hasn’t drawn a clear connection between animal protein and long-term memory loss.

He did, though, make an intriguing argument against the over-fortification of foods, especially cereals supplemented with minerals such as copper and iron. “Very few of us are deficient in these minerals, and many of us have too much,” he said. High intakes of copper have been linked to memory problems in seniors, and both copper and iron have been found in beta-amyloid plaques.

Just how much these minerals contribute to Alzheimer’s risk remains unknown, but Barnard was quick to point out that while the body may get too much iron from animal products, it only absorbs the different form of iron found in spinach and other leafy greens when stores are running low.

Limiting omega-6 fats such as corn and vegetable oil is also key for brain health, Barnard says, because these fats knock out the beneficial effects of omega-3 fats — found in fish oil, walnuts, and flaxseed — that promote blood flow to the brain.

Barnard excludes fish as a brain food because fatty fish is often contaminated with mercury, which is also toxic to the brain.

So which foods will actually help you shore up your brain’s defenses against aging? The book is careful not to single out a few magic bullet foods that will ward off memory loss — none exists — but it does emphasize the following dietary principles.

1. Make a power plate at every meal. One quarter of the plate should be filled with fruits, one quarter with grains, one quarter with legumes, and one quarter with vegetables.

2. Do colorful combinations of foods. Combining sweet potatoes with kale or oranges with apples will ensure that you get a variety of vitamins and other plant chemicals that work synergistically to promote good brain health.

3. Get creative with legumes. Vegans use these as their main source of protein, so think hummus, tofu, tempeh, as well as beans, lentils, and peas.

4. Learn to prepare foods without oil. The book recommends dry sauteeing vegetables. I’m assuming over low heat, so they won’t burn. You can also cook vegetables and grains in vegetable broth for added flavor.

5. Don’t forget the nuts and seeds. Sprinkle nuts and seeds on your salads, grains, and morning oatmeal to get omega-3 fats and vitamin E, both beneficial for the brain.

6. Skip all supplements, except one containing B12. Vegetarians often lack B12 — essential for proper brain function — in their diets since it’s found mainly in animal products such as beef, turkey, and pork, so the book recommends taking a daily supplement.

Deborah Kotz can be reached at dkotz@globe.com. Follow her on Twitter @debkotz2.
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