Published on: June 24, 2013
by Margery D. Rosen for AARP:
Antioxidants! Omega-3s! Anti-inflammatory diets! Can something you eat really help you remember — again — where you put your cellphone or reading glasses? If you add blueberries to your morning oatmeal or sip a glass of red wine at dinner, will your brain cells stay healthier longer?
Much of what we hear about the interplay between diet and brain health is based on preliminary research and then flooded in hype. As headlines have linked one food or another to Alzheimer’s disease and other illnesses, we have rushed to remove them from our diet. The problem is, as soon as one headline urges us to eat this, not that, it seems there’s another saying just the opposite.
Why all the confusion?
Proving conclusively which foods actually boost brain health is difficult and expensive, requiring large scale, long-term clinical trials. “When you’re eating blueberries, you’re not eating just one nutrient,” explains Gene L. Bowman, a brain nutrition researcher at Oregon Health & Science University. “You’re eating a complex mixture of hundreds of them. Is it the antioxidants that improved cognition or the vitamins? Most likely, it’s the unique combination of all of them.”
Still, it’s become increasingly clear that how you eat may counteract the effects of an aging brain. “The best recipe is a diet that includes brain-building nutrients such as omega-3 fatty acids, antioxidants and certain vitamins, and steers clear of foods that promote high blood pressure, high cholesterol, obesity and diabetes,” says Majid Fotuhi, M.D., chairman of Maryland’s Neurology Institute for Brain Health and Fitness and author of the upcoming Boost Your Brain: The New Art and Science Behind Enhanced Brain Performance.
It’s never too late to start reaping the benefits of a brain-healthy diet. But don’t try to detox all at once. Start slowly, and you’ll soon realize that making more healthy choices isn’t so hard after all. Here’s what you need to know.
1. Go Mediterranean
A large body of very solid research shows that a classic “Mediterranean diet” — heavy in olive oil, legumes, fish, fruits and green leafy vegetables — protects against cardiovascular disease, diabetes and cancer. The link between the diet and brain health has been less conclusive — but that’s changing.
Last year, researchers at Columbia University in New York and the University of Miami Miller School of Medicine reported in Archives of Neurology that older adults who followed a Mediterranean diet had less of the kind of damage to the brain’s small blood vessels that leads to a slowdown in mental quickness.
Previous studies by the same researchers found that the diet helped slow the onset of Alzheimer’s disease, even in those who had only followed it occasionally.
Then early this year, in the New England Journal of Medicine, Spanish scientists who had followed for five years more than 7,000 older adults at high risk for heart disease reported that those who ate a Mediterranean-style diet, including olive oil and a daily glass of red wine, showed about a 30 percent drop in heart attacks, strokes and deaths from heart disease, compared with a control group who ate more or less what they’d always eaten.
“As we age, the Mediterranean diet lowers the risk of the strokes and ministrokes that lead to Alzheimer’s pathology,” says Rudolph E. Tanzi, M.D., a professor of neurology at Harvard Medical School and director of Genetics and Aging Research at Massachusetts General Hospital. “The rule of thumb,” he says, is “what’s good for your heart is good for your brain.
“Tip: Go fish! Cold-water fatty fish are high in omega-3 fatty acids, a healthy fat linked to lower levels of beta-amyloid plaques (a sign of Alzheimer’s). Omega-3s also boost the production of Brain Derived Neurotrophic Factor (BDNF), the protein that acts as fertilizer for the brain and is responsible for ramping up memory, mood and alertness.
Opt for a 4-ounce serving of salmon, Atlantic mackerel, sardines or herring, two or three times a week. But go light on fish that are high in mercury, such as bluefish and swordfish.
2. Cut back on red meat and dairy products
Red meat is a good source of protein as well as essential vitamins and minerals, including B12, iron and zinc. But many cuts are high in unhealthy saturated fats, as are whole-milk dairy products. Saturated fats raise blood levels of the “bad” LDL cholesterol linked to heart disease and impaired memory. Harvard’s Tanzi thinks the evidence to limit meat is strong: He’s been a vegetarian for years.
Tip: If you can’t live in a world without greasy cheeseburgers, indulge occasionally.
Meanwhile, choose leaner cuts of beef, such as those with “loin” or “round” on the label, such as sirloin and round roast or steak. Avoid chuck. Other good sources of protein: beans and legumes, such as kidney beans, split peas and lentils. Nosh on an ounce a day of almonds, walnuts or cashews.
3. Ramp up foods rich in omega-3s
Your brain needs a certain amount of fat to function properly. Fats provide energy, help the body absorb essential vitamins and protect nerve cells and connections. But there are good and bad fats, and too much of the wrong kind throws a monkey wrench into the works, speeding the formation of beta-amyloid plaques.Omega-3s are among the good fats.
Research shows that they fight inflammation and support the structure of brain cells. Last year, a report in Neurology by Gene Bowman’s team at Oregon Health & Science University found that study participants (average age: 87) who had high blood levels of healthy fats, including omega-3s and a variety of vitamins (including B, C, D and E) and low levels of trans fats had less brain shrinkage and scored better on cognitive tests than those who ate less nutritious diets.
Tip: The body doesn’t produce fatty acids naturally, so you must add them to your diet. If you’re like most people, you are eating far too many inflammation-promoting omega-6 fatty acids and far too few omega-3s. What to do? In addition to eating more fish, add flaxseed to your cereal and smoothies and chia seeds to stir fries and salads. Both are stuffed with omega-3s (and have little taste). How much should you eat? According to the Cleveland Clinic, one to two tablespoons is a healthy daily dose.
4. Binge on blueberries … as well as strawberries, spinach, kale and butternut squash
Brightly colored fruits and dark green vegetables are rich in carotinoids and flavonoids — powerful antioxidants that boost BDNF and may slow the onset of dementia by repairing the damage from free radicals, unstable molecules that attack healthy cells.
In a recent study, researchers at the Brigham and Women’s Hospital in Boston found that older women who ate two or more servings of strawberries and blueberries a day were able to forestall memory decline by 2-1/2 years. Green vegetables are also high in magnesium, a potent nutrient in the war against inflammation (see sidebar).
Tip: Aim for four to five servings a day of fruits and vegetables. Besides the ones mentioned above, try avocadoes, red grapes and raisins, raspberries, plums and prunes, spinach, beets, asparagus, sweet red peppers, sweet potatoes and citrus fruits.
If you take any medications, check with your doctor before adding to your diet grapefruit, which can cut the effectiveness of a host of drugs, including many statins and antihistamines.
5. Slash trans fats
Trans fats are processed fats added to foods to extend their shelf life. These fats are double trouble — they both raise blood levels of “bad” cholesterol and lower levels of “good” cholesterol.
Bowman’s research suggests they are also bad for the brain. When his team checked the blood levels of certain nutrients in 104 elderly participants, they found that those high in trans fats had significantly lower cognitive performance and less total brain volume than those who ate a more healthy diet.
Tip: Buy and prepare fresh foods as often as possible. Packaged and processed foods are full of trans fats, so read labels and if you see “partially hydrogenated” anything, don’t buy it. Common culprits: french fries, chips, packaged baked goods, crackers, icing, stick margarine (tub margarine has less trans fat) and microwave popcorn. If you can’t or won’t cut out foods with a lot of trans fat, eat less of them, less often.
6. Take the salt shaker off the table
Doctors have warned for years that too much salt is bad for the heart. Now, a study by Canadian scientists has found that older people who eat too much salt and also fail to exercise are at increased risk for cognitive decline. According to the U.S. Department of Agriculture, if you’re 50-plus, or suffer from high blood pressure, your salt intake should max out at no more than 1,500 milligrams a day.
Tip: Liven up your dishes with herbs and spices instead of processed gravies, condiments and sauces, which tend to be high in sodium. Many herbs and spices — including ginger, parsley, oregano, basil and black pepper — are not only flavorful but high in antioxidants.
Curcumin, a key component of turmeric, found in curry powders, is believed to reduce amyloid plaque buildup. The brain benefits of these haven’t been confirmed, but they’re all better sources of flavor than salt.
7. Reduce sugar and simple carbs
So many studies have shown a link between dementia and obesity and high blood sugar at midlife that Alzheimer’s disease has been dubbed “diabetes Type 3.” Last fall, Mayo Clinic scientists found that people age 70 and older who ate a lot of simple carbohydrates (found in refined flours and rice) and sugar were nearly four times more likely to develop mild cognitive impairment than those who ate a healthier diet.
Your body does need a certain amount of sugar (glucose) to function properly. But a diet packed with sugar and the simple carbs regularly sends blood glucose soaring. High glucose levels, in turn, block blood flow to the brain, depriving it of the energy it needs to generate new neurons. Too much glucose has also been implicated in the formation of the tangles of Alzheimer’s disease.
Tip: You’re already likely eating more sugar than you need, since it’s added to many beverages and foods during processing, so don’t add it to your coffee or sprinkle it on already sweet fruits. Instead of sodas, sports drinks and sweetened coffee drinks, drink water. If you eat canned fruit, make sure the label says “in its own juice,” not sugary syrup.
The easiest way to cut down on simple carbs is to opt for whole grain rice, breads and pastas. Whole grains are digested more slowly, so glucose also is released more slowly into the bloodstream, keeping you mentally alert longer. “Whole” or “whole grain” should appear on the label before the name of the grain.
Don’t be fooled by phrases on labels that sound healthy but don’t really mean much, such as “100 percent wheat,” “cracked wheat,” “multigrain” or “stone ground.” Even better: Buy wheat berries, bulgur or farro — whole grains that haven’t yet been ground into flour.
What About …
Much has been made of the anti-aging, brain-health-boosting properties of a variety of foods and herbs, such as ginkgo biloba, resveratrol, coffee, green tea, even chocolate. Some, such as coffee and chocolate, certainly perk up your brain in the short term. But can they really forestall dementia? Most experts join the National Institute on Aging in saying the jury’s still out. “The notion that these substances will prevent cognitive decline is highly speculative at this point,” says Gene L. Bowman of Oregon Health & Science University.
He and others also advise against taking these foods and nutrients as supplements. “Food is always a better source of nutrients than a pill,” Bowman adds.
So What Exactly Is Inflammation?
To understand why diet is so critical to cognitive health you have to wrap your brain around a concept you have may have heard about but never really understood — inflammation.
“It’s a major factors driving nerve cell death in the brain,” says Harvard neuroscientist Rudolph E. Tanzi, who first identified genes linked to Alzheimer’s. Most of us think of inflammation as the protective mechanism triggered by the immune system when we get, say, a bad cut or sore throat. But experts now believe that a more insidious, low-level inflammation can occur throughout the body in response to many factors, among them a poor diet or exposure to mold and toxins.
In your blood vessels this chronic inflammation may result in high blood pressure or stroke. In your joints, it may trigger arthritis. And in your brain? Dementia. Nevertheless, the latest research shows that some dietary changes may offset the damage from oxidative stress and inflammation and increase your chances of maintaining a healthy brain well into old age.
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