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 apple 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.

Polish scientists found the levels of antioxidants which protect against heart disease and cancer are almost double in cloudy apple juice.

The antioxidants, called polyphenols, are also found in red wine, berries and dark chocolate.

In the Journal of the Science of Food and Agriculture, the researchers said the manufacturing process led to fewer polyphenols in clear apple juice.

But overall cloudy apple juice, which contains more pulp, was found to have higher concentrations of antioxidants and showed more antioxidant activity in experiments.

"I recommend cloudy juices as they contain more polyphenols and pectins. Health benefits are expected mainly in the case of cloudy apple juice consumption." - Dr. Jan Oszmianski

Polyphenols

Previous research has shown that polyphenols contained in fruit and vegetables help to protect against diseases such as cancer, by mopping up free radicals which can cause damage to cells.

Apples themselves contain a wide variety of polyphenols but when processed into apple juice some of these may be lost.

The manufacturing process used to make clear apple juice, which include using an enzyme to break down the pectin in apple cell walls and spinning to remove pulp, considerably decreases the levels of polyphenols in the end product, Dr Oszmianski explained.

"A lot of polyphenols are lost when you make a clear juice. It could also be that because you're retaining that cloudiness and pectin there's the additional benefit of fibre. If you're interested in health, you should go for a non-clarified apple juice." - Dr Paul Kroon

Dr Kroon said eating an apple would be better than drinking apple juice, although farmers had been growing sweeter less astringent varieties with fewer polyphenols.

"Before we knew about the them, polyphenols were bred out of apples and now we're looking at putting them back," he said.

Judy Moore, spokesperson for the British Dietetic Association and registered dietitian said: "Almost doubling your intake of apple polyphenols by switching from clear to cloudy juice seems an easy option for apple juice drinkers.

"Don't forget that eating apples offers more health benefits than drinking apple juice as you also get the fibre in apples."

Easy on the digestion, apples contain malic and tartaric acids that inhibit fermentation in the intestines. Their high fiber content adds bulk that aids the digestive process, making elimination natural and comfortable. Apples contain pectin, a soluble fiber that encourages the growth of beneficial bacteria in the digestive tract.

Apples contain flavonoids, antioxidants that improve immune function and prevent heart disease and some cancers.

Green apples act as a liver and gall bladder cleanser and may aid in softening gallstones.

Because of their high water content, apples are cooling and moistening and aid in reducing fever. Simply grate them and serve them to feverish patients. Steamed apples sweetened with honey are beneficial for a dry cough and may help to remove mucous from the lungs.

Hippocrates (circa 400 BCE), the Greek physician considered the father of medicine, was a proponent of nutritional healing. His favorite remedies were apples, dates, and barley mush.

Today medical practitioners are beginning to recognize that the apple's abundant quantity of pectin is an aid in reducing high cholesterol as well as blood sugar, a wonder food for people with coronary artery disease and diabetes.

If these aren't enough reasons to "eat an apple a day," there's more. Eating raw apples gives the gums a healthy massage and cleans the teeth. This popular fruit is said to have properties that are a muscle tonic, diuretic, laxative, antidiarrheal, antirheumatic, and stomachic.

Though cloudy apple juice tops clear in antioxidant levels, both cloudy and clear apple juice contain phytonutrients and flavinoids that improve overall health and can reduce risk of certain diseases. Phytonutrients and flavonoids are contained in fruits and vegetables, and continuous research is uncovering their positive effect on the human body. Research on asthma has shown that apple juice consumers (with asthma) had lower risk of respiratory disease and better lung function than asthma patients who did not consume apples or apple juice. Another study showed a decreased incidence of lung cancer in individuals who consumed apple products. In addition, the phytonutrients in apple juice can prevent the oxidation of bad cholesterol; oxidation of bad cholesterol leads to plaque build up in arteries and inhibits cardiovascular function, leading to heart disease. In fact, drinking apple juice while eating a hamburger can help protect your body from the fats in the burger!

Apple juice also provides sugars and fluids to the body, and tastes sweet enough that children will readily drink it. One serving of 100% apple juice (serving size is 4-6 ounces) is regarded as a fruit exchange following USDA guidelines, so apple juice will count toward daily fruit intake. Apple juice is also very unlikely to cause an allergic reaction in anyone and is digested easily - probably why it is recommended by pediatricians as a first juice for infants.