Apples May Slow Signs of Aging For Fruit Flies

A study conducted in Hong Kong evaluated the role of apples in slowing the aging process by altering genes that produce antioxidant enzymes in the body. The study used fruit flies by feeding them apple extracts and seeing what effect it had on their lifespan and aging process. Apples contain powerful antioxidants called apple polyphenols. The present study demonstrated that “apple polyphenols in the diet could prolong the mean lifespan, attenuate the oxidant induced mortality rate, and partially reverse the decline of the fruit flies’ ability to climb.”

The damage that free radicals or oxidants cause plays a central role in the aging process. Important free radicals include hydrogen peroxide and superoxide anion. In the experiments on fruit flies, oxidant injury was produced by exposing fruit flies to hydrogen peroxide and paraquat, a common pesticide. Usually such exposure results in a decrease in the lifespan of fruit flies. In the present study, researchers aimed to examine whether apple polyphenols played any role in protecting against such oxidant-induced aging. In addition, they wanted to assess the expression of genes of enzymes that nullify the effect of oxidants.

* Fruit flies taken for the study were first exposed to oxidants such as hydrogen peroxide and paraquat, a commonly used pesticide. Apple polyphenols were extracted from Red Fuji apples. Two-hundred flies were given a control diet and 200 were fed on an apple polyphenol enriched diet. This was continued for 74 days. The number of dead flies was calculated every two to three days.
* In the second part of the experiment, the same procedure was repeated, but this time some of the flies were killed to assess the expression of genes that synthesize super oxide dismutase and catalase enzymes.
* Later, the climbing capacity of the flies in each group was assessed by placing them in a vial and noting their upward movement.

* There was 3 percent increase in the average lifespan of flies that were fed on an apple polyphenol enriched diet. In fact, the 50 percent survival time had increased in the test group, from 50 days to 55 days.
* Apple polyphenols did not have a significant effect on the maximum lifespan of the fruit flies.
* In the test group, there was a significant increase in expression of genes that were responsible for production of superoxide dismutase and catalase.
* Supplementation of apple polyphenols in the diet could partially reverse the pesticide-induced lifespan decline

Shortcomings/Next steps
This experimental study was conducted on fruit flies. Although fruit flies and humans share some genes, the extent that the results of this study apply to humans is questionable. Besides, the apple extract contains many other substances such as catechins and chlorogenic acid, apart from polyphenols. Therefore, attributing the beneficial effects solely to apple polyphenols is not reasonable.

Many earlier studies on humans have iterated the oxidant-reducing capacity of apples. The mechanism of this protection, however, was not clear. The present study has convincingly shown that apple polyphenols increase the expression of genes coding for enzymes that nullify the effects of oxidants. This explains the mechanism by which apples are able to protect our cells from oxidant damage and retard the process of ageing. Apart from ageing, some diseases such as coronary heart disease and degenerative diseases of the brain also occur because of damage by oxidants. So, eating apples may be beneficial to people who are at risk of developing these diseases.

For More Information:
Apple Polyphenols Extend the Mean Lifespan of Drosophila Melanogaster
Publication Journal: Journal of Agricultural and Food Chemistry, February 2011
By Cheng Peng; Ho Yin Edwin Chan; Chinese University of Hong Kong, China

*FYI Living Lab Reports Are Summaries of the Original Research.

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