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Food for thought: Can diet protect memory?

Prevention of age-related memory loss may be no further away than your own refrigerator and no more expensive than a bag of groceries, experts say.
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As concern over Alzheimer’s disease grows, more Americans are turning to expensive and potentially unsafe supplements that claim to enhance memory. But prevention of age-related memory loss may be no further away than your refrigerator, and no more expensive than a bag of groceries, experts say.

With the aging population of baby boomers in the United States, more research is being done than ever before on diseases such as Alzheimer’s and other forms of dementia. Scientists are developing a better understanding of why memories fade, and along the way they are finding new ways to combat the decline.

For one thing, research increasingly suggests that diet may be important in preventing Alzheimer's.

Inside the aging process
As the brain ages, it loses the ability to protect itself from the barrage of commonplace dangers it faces every day, particularly inflammation and oxidation, a process which allows damaging free radicals to attach themselves to cells.

While it's not entirely clear what causes Alzheimer's disease, amyloid plaque — a goopy, fibrous substance akin to fur balls in the brain — plays a key role. As the plaque builds up, it causes more oxidation and inflammation, and begins to kill off brain cells.

In addition, brain cells often stop communicating with each other as people age, making it harder for the brain to process thoughts, retain short-term memory and create new cells.

“Old neurons are like old married couples — they don’t talk to each other very much anymore. They just sit in the room with the remote and stare at the TV,” says Dr. James Joseph, director of the Neuroscience Lab at the Human Nutrition Research Center on Aging at Tufts University in Boston.

Older dogs can learn new tricks
While research in the field of aging and nutrition is still in its infancy, scientists have found that diet may help minimize the brain's sensitivity to oxidation and inflammation, as well as improve brain cells’ ability to communicate with each other.

One of the most intriguing areas of research involves the role of antioxidants, potent chemicals in plants that protect against free radicals, highly active molecules that damage cells. Antioxidants are what give fruits and vegetables their bright colors. Plants produce these chemicals to protect themselves from environmental insults, such as pollution, and when humans eat plants, they also reap the protective benefits.

In a study involving about 70 beagles, Dr. Carl Cotman, director of the Institute for Brain Aging and Dementia at the University of California, Irvine, found that older dogs fed a diet rich in antioxidants over several years were able to perform tasks — and learn new tricks — far better than fellow canines fed a normal diet.

“We rejuvenated a capacity in the aging brain which wasn’t there in the beginning and wasn’t coming back on its own," says Cotman. "It indicated the brain has a capacity to recover some age-related loss of cognitive function."

Moreover, MRI scans later revealed structural changes in the brains of the dogs on the antioxidant diet, most notably a decrease in the buildup of amyloid plaque.

A cornucopia of benefits
While it’s unclear exactly how the antioxidants affected the dogs, Joseph, co-author of “The Color Code: A Revolutionary Eating Plan for Optimum Health,” says many fruits and vegetables primarily valued for their powerful antioxidants may in fact provide multiple benefits for the aging brain. They may not only slow oxidation, but may also act as anti-inflammatory agents, make the brain less vulnerable to amyloid plaque, improve communication between neurons and allow the brain to regenerate — all of which contribute to better memory in old age.

Purple fruits and vegetables, such as blueberries, cranberries and Concord grapes, may be especially beneficial for the brain, says Joseph. In a study on aging mice genetically engineered to develop Alzheimer's, Joseph was able to improve their cognitive function by feeding the animals a diet high in blueberries.

In addition to better memory and motor skills, Joseph found that the mice had fewer signs of damage from oxidation and inflammation in their brain tissue than did mice fed a standard diet. They also had higher levels of chemicals necessary for brain cells to regenerate and communicate.

While it’s still too early to tell if the animal studies apply to humans, it’s quite possible that "what’s going on in the rat may be what’s going on in a human," says Joseph, who published the results of the study last year in the journal Nutritional Neuroscience.

In addition to particular fruits and vegetables, scientists believe that curcumin, a spice used in India and known for its anti-inflammatory effects, may prevent memory loss. Curcumin is what gives yellow curry its bright color and is frequently used as a natural food dye.

In a study on genetically engineered mice, Dr. Greg Cole, associate director of the Alzheimer’s Center at the University of California, Los Angeles, found that curcumin helped reduce amyloid plaque in the animals, and also limited damage from oxidation and inflammation. The results of the study were published in 2001 in the Journal of Neuroscience. A clinical trial is now under way at UCLA to test curcumin in people and find an effective dose.

New research has also shown that B vitamins, such as niacin and folic acid, are vitally important to brain function and may help keep the mind sharp. Found in a range of foods, including lean meat, fish, legumes, dairy products, grains and green, leafy vegetables, B vitamins appear to help control inflammation and may play a role in the development of new brain cells.

Supplements may not do the same
Given the growing evidence of the benefits of antioxidants and other chemicals on the brain, why not just take specific supplements to prevent memory loss?

Most researchers caution that sources of antioxidants from food are far more effective — and safer — than supplements. Although it isn't precisely known how the chemicals work, it’s believed that they act in combination with one another.

In addition, different chemicals in plants protect against different kinds of damage, and there may be additional but as yet undiscovered substances in plants that work with antioxidants to provide the protective effects.

Part 2: What's good for the heart is good for the brain