Just as a healthy diet can help fend off chronic diseases like heart disease and type 2 diabetes, what you eat also can help you keep your mental edge as you age. Approximately five million Americans over age 65 have Alzheimer's disease, a progressive disease that destroys brain cells and the most common form of dementia. Second to Alzheimer's disease is vascular dementia, which occurs when the blood vessels of the brain become damaged and prevent adequate blood supply to parts of the brain.
Research highlights the cognitive benefits of diets rich in fruits, vegetables, fish, legumes and healthy fats, a pattern similar to a Mediterranean diet. Older Americans consuming such a diet had less damage to the small blood vessels in their brains, according to a study published in the February 2012 issue of Archives of Neurology. The researchers scored the diets of nearly 1,000 men and women, based on higher consumption of fruits, vegetables, legumes, cereals and fish; mild to moderate consumption of alcohol; a higher intake of monounsaturated fats compared to saturated fats; and lower consumption of meat and dairy products. The more closely the diet matched a Mediterranean diet, the less small blood vessel damage. Another U.S. study measured changes in cognitive status of more than 17,000 middle-aged to elderly participants and found that those whose diets most closely resembled a Mediterranean-style diet were the least likely to develop cognitive impairment.
Good for the heart, good for the brain
Studies have identified links between a heart-healthy diet--such as a Mediterranean pattern--and a brain-healthy diet. "The triangle connecting a healthy heart, a healthy brain, and a healthful diet has a strong scientific base," says Irwin Rosenberg, M.D., Professor of Nutrition at the Friedman School of Nutrition Science & Policy at Tufts University. Heart-healthy nutrition promotes healthy blood vessels--open and free of atherosclerosis--that provide nutrients to the heart. Likewise, diet helps to maintain the integrity of the blood vessels of the brain. And a healthy heart pumps oxygen and nutrients to the brain. So it is not surprising that the same dietary factors are preventative of both heart disease and brain aging.
Nourish your mind. Follow these four diet strategies to boost brain protection:
1. Eat your fruits and vegetables. Women should aim for 1Â½ cups of fruit and 2Â½ cups of vegetables per day, and men should aim for 2 cups of fruit and 3 cups of vegetables per day. Diets rich in produce provide ample potassium, a mineral important for healthy blood pressure levels, which help protect the brain and the heart. High blood pressure can damage the lining of the arteries in your brain, making them stiff, which can block blood flow. Sources include potatoes, prunes, white beans, lima beans, sweet potatoes, oranges, bananas, tomatoes, spinach, apricots, cantaloupe, avocado, broccoli, and many other fruits and vegetables. Some fruits and vegetables deserve special mention.
--Apples and pears. One study found that a high consumption of apples, pears and other white fruits and vegetables may protect against stroke.
--Berries. These tiny nutrient powerhouses are rich in anthocyanins, a type of phytochemical. In the Nurses' Health Study, greater intakes of blueberries and strawberries were associated with slower congitive aging (by as much as two and a half years) among older women.
--Spinach. Lutein, a relative of beta-carotene, may boost cognitive performance in older adults, says Elizabeth Johnson, Ph.D. of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. In a recent study, Johnson and colleagues gave older women a lutein supplement for four months and measured cognitive decline by having subjects name as many items in a category as possible in a one-minute period; the number of items named increased from the beginning of the study to the end of the supplementation period. "It didn't just slow decline. There was an improvement," says Johnson. You can find lutein in leafy greens, winter squash, corn, peas, broccoli, pistachios and egg yolks.
2. Go fish. One study found that older adults who ate baked or broiled fish at least once weekly had greater volume of gray matter in the areas of the brain important to Alzheimer's disease, and showed slower rates of developing dementia or mild cognitive impairment. Only 3.2 percent of the subjects who ate the most fish developed either dementia or mild cognitive impairment, while nearly 31 percent of non-fish eaters suffered cognitive decline. One component of fish that may be brain boosting is the omega-3 fatty acid, DHA. Johnson studied the effects of supplementing with DHA and DHA + lutein. Both the lutein and DHA groups showed improvements in verbal fluency, but the combined DHA + lutein group also demonstrated improvements in memory and learning, suggesting that DHA and lutein may work together to improve cognitive function. Eating more DHA-containing fish increases DHA in the brain's gray matter, says Leah Gillingham, Ph.D. of the Richardson Center for Functional Foods and Nutraceuticals at the University of Manitoba. There it plays a structural role in the brain, and "it has a role in the resolution of inflammation," she adds.
--Choose baked or broiled fish (not fried or breaded) that are high in omega-3 fatty acids such as salmon, sardines, tuna and trout.
3. Healthy fats for the brain. Diets high in saturated fats appear to harm cognition, whereas eating foods rich in monounsaturated fats might help. A study published in the May 2012 issue of Annals of Neurology found that older women who ate the most saturated fat had the poorest scores on cognitive function and memory tests over four years compared to women who ate the least. And those who ate the most monounsaturated fat, found in nuts and in olive and canola oils, scored higher on cognitive function and were at lower risk of mental decline.
--Cook with vegetable oils instead of butter and margarine.
--Snack on nuts instead of sweets.
--Replace cheese with avocado in sandwiches.
4. Coffee and tea. Tea contains the amino acid L-theanine, which shows neuroprotective effects, says Tammy Maria Scott, Ph.D., assistant professor at the Tufts University School of Medicine. Coffee, too, appears to protect the brain. This might occur "through antioxidant or anti-inflammatory mechanisms or through a reduction in brain levels of amyloid-beta, an abnormal protein that is part of Alzheimer's disease pathology," she explains.
--Enjoy coffee, tea, or both, daily, unless you have a medical reason not to. Check with your doctor before starting or increasing your coffee or caffeine intake, advises Scott.
(Environmental Nutrition is the award-winning independent newsletter written by nutrition experts dedicated to providing readers up-to-date, accurate information about health and nutrition in clear, concise English. For more information, visit http://www.environmentalnutrition.com.)
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