February 11, 2008

Apples May Improve Health

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An apple a day may now actually keep a specific doctor away. Recently, Cornell food scientists discovered that apples, along with a family of other fresh fruits and vegetables, may diminish the risk of developing neurodegenerative disorders, such as Alzheimer’s disease.
Prof. Chang Y. Lee, Food Science and Technology, lead researcher in the study, has teamed with visiting scientists and a slew of graduate and postdoctoral students to tackle research that has spanned more than 15 years.
According to Lee, in the early stages of the study researchers identified the chemical structures of a number of bioactive phenolic compounds in apples. These phenolic compounds participated in a variety of functions performed by antioxidants, which include anything that inhibits reactions promoted by oxygen.
Putting the two findings together, Lee reported that his team found these phenolics protected in vitro oxidative stress-induced neuronal cell death. Additionally, according to an article by the team published in a December 2004 edition of the Journal of Food Science, oxidative stress is believed to be responsible for the onset of neurodegenerative disorders such as Alzheimer’s disease. Put simply, the researchers proposed that the newly discovered compounds in apples may combat the ingredients for a neurodegenerative disease.
More specifically, Lee explained that his team focused on in vitro rat neuron cells that had been exposed to oxidative stress.
“We found that these fruits prevented oxidative stress-induced neurotoxicity and membrane damage,” Lee said.
According to the article it published, the team exposed a number of the rat cells in question to various concentrations of the apple phenolics, while depriving a different group of cells from contact with the phenolics. After exposing both groups to hydrogen peroxide for two hours, those that had not been pre-treated with the phenolics showed an increase in oxidative stress levels, whereas those that had received the pre-treatment showed a reduction in the stress levels.
Since Alzheimer’s disease is linked to heightened oxidative stress levels, the phenolic compounds in apples could thus theoretically be linked to the prevention of the disease.
What began as research strictly confined to the biochemical and nutritional aspects of apples later grew to include the study of the health benefits of comparably popular fruits such as bananas and oranges.
­­­“We published two years ago a [work] on apples. Since then I have received many inquiries from the general public about oranges. That is why we conducted this additional research,” Lee said.
Upon testing bananas and oranges in a similar fashion to that discussed above, the researchers found that apples showed the highest reductive activity.
According to Lee, the team located more antioxidants in apple skins than the apple flesh, suggesting that the risk reducers for disease are concentrated on the surface of the fruit. Furthermore, Lee reported that the apple phenolics they studied in vitro had cancer chemo-preventive effects as well as tumor-preventative activity. The latter findings hint towards apples’ possible ability to hinder the onset of cancer.
Cornell researchers, however, are not the only ones interested in the non-taste components of food.
According to Lee, several scientists at a number of institutions are currently conducting research on the health benefits of fruits, vegetables, herbs and nuts, among others.
“[There is] a group at Rutgers University working on green tea, a Harvard University group working on resveratrol in wine and grapes, and a [United States Department of Agriculture] group in Boston working on blueberries [and their effects] on memory and dementia,” Lee said.
As the Cornell team looks ahead to the future, it hopes to incorporate actual human subjects. Currently, according to Lee, all of the team’s findings are elicited from in vitro studies, and therefore can only prove the possibility of the reduced risks of disease.
“We do not know yet the exact bioavailability of those antioxidants in the human body,” Lee said. “In order to confirm the final certainty, we should have large scale human clinical studies — that is the future study.”