May 18, 2007 -- Apples may be appealing for a very good reason. A new study shows the bulk of apples' anticancer properties lie in the peel.
Researchers analyzed the chemical composition of apple peels and identified a group of phytochemicals that proved potent against at least three different types of human cancer cells: breast, colon, and liver.
Countless studies have supported the old adage "An apple a day keeps the doctor away" by showing a diet rich in fruits and vegetables reduces the risk of cancer, heart disease, diabetes, and a host of other chronic diseases.
But researchers say they're just beginning to understand exactly which compounds found in fruits and vegetables are responsible for these healthy benefits. Much of the recent research has focused on the anticancer properties of a group of phytochemicals known as phenolics, which are typically found in the seeds and skins of fruit and vegetables.
Testing Apple's Appeal
Apples are the largest source of phenolics in the American diet, representing 22% of all fruit phenolics consumed in the U.S. The average phenolic content of an apple ranges from 110 milligrams to 347 milligrams per 100 grams of fresh apple. Apples are also high in another group of healthful compounds known as flavonoids.
In the study, published in the Journal of Agricultural and Food Chemistry, researchers processed 231 pounds of Red Delicious apples and extracted the chemical content of about 24 pounds of apple peel.
They then screened the chemical compounds for potential anticancer properties and identified a group of phytochemicals with powerful anticancer effects. The results showed apple peels had more potent antioxidant activity and anticell proliferation properties against human cancer cells than apple flesh did.
Researchers say the study shows that apple peel may account for the lion's share of apple's anticancer and antidisease properties and should be regarded as a rich source of nutrients and antioxidants.