An Apple a Day

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An Apple a Day

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How the famed fruit protects the brain

By Psychology Today.com

An apple a day keeps the doctor away, as the saying goes. And not

just any doctor. An apple a day may help keep the neurologist away—

along with the cognitive decline that often accompanies aging and

neurodegenerative diseases like Alzheimer's and Parkinson's.

Food scientist Chang Y. Lee recently found that a nutrient in apples

can protect rat brain cells from damage. The nutrient, an

antioxidant called quercetin, provided even more protection than

Vitamin C, which is known to combat neurodegenerative diseases in

humans.

Quercetin belongs to a group of substances getting a lot of

attention these days—flavonoids. These are naturally occurring

chemical compounds that help give plants their color. Most

flavonoids, as well as certain vitamins and minerals, are potent

antioxidants; they neutralize harmful free radicals of oxygen,

produced when cells burn oxygen for energy. If left unchecked, free

radicals cause cumulative cell damage that may lead to cancer or, in

the case of brain cells, Alzheimer's, Parkinson's or other age-

related mental decline.

" Quercetin has much higher antioxidant activity compared to other

flavonoids and Vitamin C, " says Lee. His work has shown that not

only may quercetin help brain cells, but also it may actually hurt

cancer cells. In his lab experiments, quercetin blocked some of the

pathways by which tumors grow out of control, and once again, in

this task quercetin outperformed Vitamin C.

Apples are a primary source of quercetin. The same flavonoid is also

found in onions, tea, blueberries and cranberries.

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Powered by: PsychologyToday.comOther research suggests that

quercetin may have a variety of benefits in combination with other

nutrients. A Dutch study found that a high intake of black tea,

which contains a variety of flavonoids in addition to quercetin,

reduces the risk of heart disease, and a Finnish study found that

people who ate the most whole apples had a lower risk of stroke than

those who ate the least.

Substances that protect the heart and its circulation generally

protect the brain as well. The common denominator is the network of

blood vessels so crucial to both organs. Damage to blood vessels in

the brain may impair the communication lines between nerve cells

that underlie all mental activity.

Lee can't say for sure yet whether quercetin can halt

neurodegeneration in people. Clinical trials or studies of large

populations are needed to see whether his lab results hold up in the

real world.

In the meantime, though, Lee heartily recommends apples for

everyone. Given the potential benefits of quercetin, plus the other

nutritious qualities of apples, he suggests that people add an apple

to the mix of fruits and vegetables that they eat each day.

" One apple a day provides a significant amount of quercetin and

flavonoids, " he notes. The exact quantity of quercetin in an apple

varies depending on the year, season and region the apple was grown

in. But all apples—from red delicious to fuji—have a large amount.

Choose a fresh apple over applesauce or apple juice for a snack, Lee

suggests, since quercetin resides primarily in the skin of the

fruit. " Processed food may always have a chance to lose active

compounds, " he adds.

He also warns against supplements, because large doses of purified

quercetin may prove dangerous. And it may turn out that quercetin

works best just as nature intended it to be consumed—in concert with

other substances in whole foods.

Although Lee has devoted the past 20 years to studying apples, he

admits that quercetin also shows up in blueberries, cranberries and

onions. " But how much onion can you eat per day? " he asks.

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By son

Last Reviewed: 13 Jun 2005

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