An Apple A Day Keeps the Doctor Away
(June 22, 2000) -- Two Cornell University food researchers have added scientific weight to an old saying: An apple a day keeps the doctor away.
Writing in today's issue of the prestigious journal Nature, Rui Hai Liu and Chang Yong "Cy" Lee report that trace chemicals in apples help protect against cancer.
And it's the combination of the nutritional compounds called phytochemicals -- not just solitary superstars like vitamin C -- that give fresh produce its cancer-fighting properties.
"Eating fruits and vegetables is better than taking a vitamin pill," said Liu, an assistant professor of food science. He used extracts from 25 varieties of New York state apples to suppress liver and colon cancer cells in laboratory tissue samples. "
An extract from apple skins, the most nutritionally dense part of the fruit, inhibited colon cancer cells by 43 percent. Liver cancer cells were inhibited by 57 percent.
Some varieties of apples performed better than others. Among the stars: Fuji, Spartan and Red Delicious.
And fresh is better, the researchers say.
"We're not eating fresh apples as much as we should," said Lee, a 20-year apple researcher and professor at Cornell's New York state Agricultural Experiment Station in Geneva.
Lee started to explore the apple-health connection five years ago, after 15 years of studying the layer of enzymes that make a cut apple turn brown.
Lee said Americans eat the equivalent of one-fifth of a fresh apple each day, or about 19.7 pounds a year. But they should eat five times that much -- at least one apple a day, he said.
The Cornell researchers found that just 100 grams of apple have the same antioxidant activity as 1,500 milligrams of Vitamin C. (The average apple weighs 150 grams, or about 5 ounces.)
Phytochemicals such as flavanoids and polyphenols are antioxidants. They soak up oxidants, the tissue-damaging free oxygen molecules thought to contribute to cancer.
Apples and other fresh fruits and vegetables are better than "nutriceuticals" made from dried and ground produce, said Lee. The whole foods not only contain fiber, trace minerals and vitamins, but in the stomach they displace foods that are high in saturated fat and high in cholesterol.