The Real Deal About the Apple Peel

My wife and I have a great relationship when it comes to apples: she eats the fruity insides while I eat the skins. No matter how hard I try, I can't seem to convince her that the apple PEEL is more important that the apple. Granted, the skins don't taste nearly as good, but according to current research, the apple skin is IN.

Traditionally, apple peels have been considered healthy because of their fiber content, as the peel contains about 75 percent of the dietary fiber in an apple.

But a recent study has shown that the peel also contains most of the beneficial phytochemicals (substances found in edible fruits and vegetables that at exhibit a potential for preventing disease, in particular for reducing the risk of cancer) responsible for apples' anti-carcinogenic effects.

According to a May 22 article in ScienceDaily.com, researchers processed more than 200 pounds of Red Delicious apples, and extracted phytochemicals from about 24 pounds of peel. They screened the compounds for anti-cancer effects in laboratory cultures of human liver, breast, and colon cancer cells, and identified a group of compounds with potent anti-cancer properties.

An article in Journal of Agriculture and Food Chemistry (May 30, 2007) points out that specifically,13 triterpenoids (anti-cancer agents) from the peels of Red Delicious apples were identified and confirmed to be highly effective against cancer. Evidence suggests that a diet high in fruits and vegetables may decrease the risk of chronic diseases, such as cardiovascular disease and cancer. Phytochemicals including phenolics, flavonoids and carotenoids from fruits and vegetables may play a key role in reducing chronic disease risk.

According to an article in WebMD.com (May 18, 2007), epidemiological studies have linked the consumption of apples with reduced risk of some cancers, cardiovascular disease, asthma, and diabetes. In the laboratory, apples have been found to have very strong antioxidant activity, inhibit cancer cell proliferation, decrease lipid oxidation, and lower cholesterol. Apples contain a variety of phytochemicals, including quercetin, catechin, phloridzin and chlorogenic acid, all of which are strong antioxidants. The phytochemical composition of apples varies greatly between different varieties of apples, and there are also small changes in phytochemicals during the maturation and ripening of the fruit. Storage has little to no effect on apple phytochemicals, but processing can greatly affect apple phytochemicals.

Much of the protective effect of fruits and vegetables has been attributed to phytochemicals. In fact -- according to cancerfocus.net -- thousands of phytochemicals have been identified in foods, yet there are still many that have not been identified. Different phytochemicals have been found to possess a range of activities, which may help in protecting against chronic disease. For example, phytochemicals may inhibit cancer cell proliferation, regulate inflammatory and immune response, and protect against lipid oxidation.

According to nutrientreference.com, a major role of the phytochemicals is protection against oxidation. We live in a highly oxidative environment, and many processes involved in metabolism may result in the production of more oxidants. Humans, and all animals, have complex antioxidant defense systems, but they are not perfect and oxidative damage will occur. Both cardiovascular disease and cancer are thought to be particularly the results of oxidative stress, which can lead to damage of the larger biomolecules, such as DNA, lipids, and proteins. It has been estimated that there are 10,000 oxidative hits to DNA per cell per day in humans.

The Journal of Agriculture and Food Chemistry article points out that a major class of phytochemicals found commonly in fruits and vegetables are the flavonoids. Apples are a very significant source of flavonoids in people's diet in the US and in Europe. In the United States, twenty-two percent of the phenolics consumed from fruits are from apples making them the largest source of phenolics. In Finland, apples and onions are main sources of dietary flavonoids, while in the Netherlands apples rank third behind tea and onions as top sources of flavonoids. In a Finnish study of approximately 10,000 people, flavonoid intake was associated with a lower total mortality.

Apples -- previously been linked to a reduced risk of lung cancer, heart disease, and stroke -- were one of the main sources of dietary flavonoids that showed the strongest associations with decreased mortality.

There's a lot of truth to the old adage, "An apple a day keeps the doctor away," but we probably need to add that it's the apple SKINS that do most of the work.