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Cornell Daily Sun  

Apples May Keep Alzheimer's at Bay
December 02, 2004
by Rachel Weiss
Sun Staff Writer

Although many may have dismissed the advice as a cliché, there is now further scientific evidence that eating an apple a day truly does keep the doctor away. Chang Y. Lee, professor of food science at Cornell University's New York State Agricultural Experiment Station in Geneva, N.Y., and fellow researchers have identified bioactive compounds in apples that have strong antioxidant qualities. These chemicals, most notably the phytonutrients quercetin and phenolic acid, promote effects that may protect brain cells from developing neurodegenerative diseases such as Alzheimer's and Parkinsonism.

Lee has been studying apples for the past two decades, investigating their chemistry and nutritional qualities, but only in the past year and a half has his team delved into the exploration of quercetin. Experiments with rat brain cells have shown quercetin and phenolics to be principal factors in preventing cell damage.

"What we found was that the apple phenolics, which are naturally occurring antioxidants found in fresh apples, can protect nerve cells from neurotoxicity induced by oxidative stress," said Lee.

Oxidation arises when abnormal cells called free radicals attack healthy cells and seize essential molecular components. Antioxidants neutralize the production of toxic substances in the body and thus suppress the damaging assaults by free radicals. Fruits and vegetables are common sources of antioxidants, and among those, apples, berries and onions are the best choices for absorbing quercetin.

The recent studies augment the accumulating body of knowledge detailing the health benefits of apples. In 2000, Lee found that phytochemicals in the fruit boast stronger antioxidant power than vitamin C against colon and liver cancer cells. In addition, a 2002 report he authored discovered that quercetin fights cancer activity more effectively than vitamin C.

Lee's study on apple phenolics, co-authored by Ho Jin Heo, a visiting fellow at Cornell, and D.O. Kim, a postdoctoral researcher at the university, along with S.J. Choi and D.H. Shin at Korea University, compared two groups of rat neuronal cells. Results revealed that the experimental group, pretreated with apple phenolic extracts, fared better against toxic hydrogen peroxide than the control group.

In the second study, Lee and Heo found additional evidence to support earlier theories that quercetin has much stronger antioxidative and anticarcinogenic qualities than vitamin C. These findings do not suggest that vitamin C is an insignificant compound, only that it does not aid in the protection on neural brain cells.

Prof. David Levitsky, nutritional science, cautions that it is important not to generalize the results of these studies. "It was an in vitro study of ... one of the compounds in apples that has antioxidant properties. We will have to wait for many more animal, then human studies, before we will know for [certain] whether eating an apple a day prevents neural degeneration." Lee also stresses that his studies were conducted solely in laboratory settings, and that clinical trials with human subjects have not yet been performed.

"We have a long way to absolutely prove [quercetin] works the same way in the human brain but let's say there is great potential," Lee said in a recent article in the Seattle Post-Intelligencer.

The apple extracts utilized in the research are of the red delicious variety and were grown in upstate New York. The study found that a deeper red pigment in the apple signified a greater concentration of quercetin.

Danielle Peress '06, a student of Levitsky's, found the studies both interesting and relevant. "I always knew apples were a healthy choice, but its great having this research document their explicit benefits."

(more news)

Can I just eat apples? Read the frequently asked questions here
Are apple polyphenol extracts safe? Read the toxicity study here


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