Vienna, Va. – Turns out whoever penned that centuries-old adage about "an apple a day" was right: A newly-released study is reporting that components found in apples may keep the doctor away by reducing the risk of many chronic diseases, including heart disease, cancer, stroke, type 2 diabetes and asthma.

Researchers at the National Public Health Institute in Helsinki, Finland, reported their findings in the September American Journal of Clinical Nutrition. Their conclusions were based on ongoing research of 10,054 Finnish men and women that began in 1966. They sought to study the potential association between intake of the flavonoid class of plant-based "phytonutrients" and reduced risk of several chronic diseases.

"Of all the main flavonoid sources, apple intake was associated with [a reduced risk of] almost all of the chronic diseases considered," the authors, led by Dr. Paul Knekt, wrote.

Apples: Whole Body Health Food
According to analysis of an extensive body of data over many years, those study participants who ate the most apples and the flavonoid quercetin had the lowest risk of total mortality — that is, they had the lowest risk of dying of any cause during the decades-long study. High consumption of quercetin — and especially quercetin-rich apples — was also associated with the lowest risk of dying from ischemic heart disease, which includes any heart diseases characterized by reduced blood flow in the heart, such as caused by plaque build-up (i.e., arteriosclerosis). High apple consumption was also associated with reduced risk of thrombotic stroke, a type of stroke where a blood clot starves part of the brain of oxygen.

The chance of developing any type of cancer was lowest among those consuming higher quercetin levels. Breast cancer incidence tended to be lower with higher quercetin intakes, and the association between reduced risk of lung cancer and increased quercetin consumption, and in particular apple consumption, was especially strong.

The chance of developing type 2 diabetes was lowest with higher quercetin intake, with apples showing the strongest association of all quercetin-containing foods. Asthma incidence was also lower with higher flavonoid intake, with apples again showing the strongest association.

As the incidence of obesity has risen sharply in this country in recent years, so has the incidence of obesity-related illness including heart disease, cancer and diabetes. Childhood asthma has also increased significantly, suggesting that Americans could improve their health by controlling their weight, and eating more fruits and vegetables — at least five servings per day, according to the U.S. Department of Agriculture's Food Guide Pyramid, the federal government's advice on food intake for better health.

"This research adds to the growing body of science demonstrating that eating apples and apple products may improve health in many ways," said Dianne Hyson, Ph.D., R.D., of the University of California-Davis, considered the world's leading expert on apple nutrition research.

Quercetin Gets Spotlight Again
Overwhelmingly, Finnish researchers pointed to the flavonoid quercetin — a plant-based "phytonutrient" found most abundantly in apples, onions, tea and red wine — as the flavonoid with the best potential health-promoting capabilities.

"The potential benefits were mainly ascribed to quercetin, the most potent antioxidant," Knekt and his colleagues wrote. They noted that there may be alternative explanations for their findings, such as that some other substance or substances in apples may have been responsible for the observed associations.

Quercetin is found in fresh apples, as well as in apple juice — suggesting that that "apple a day" can be eaten or drunk, say apple industry nutrition experts.

"This study confirms what health professionals have been preaching for years — that there are benefits to consuming whole foods like apples, apple juice or applesauce, since those invisible phytochemicals play such an important role in maintaining good health," said Sue Taylor, M.S., R.D., director of nutrition communications for the Processed Apples Institute, Atlanta, Ga. She noted that research at UC-Davis also confirmed that the phytonutrients found in apples do pass through to apple juice.

Numerous previous studies have suggested that quercetin, and particularly quercetin-rich apples, may promote health. In March 2001, researchers at the Mayo Clinic in Rochester, Minn., reported that quercetin reduced or prevented the growth of prostate cancer cells in a laboratory study that was published in the journal Carcinogenesis. In January 2000, researchers at the University of Hawaii reported in the Journal of the National Cancer Institute that increased consumption of quercetin was associated with a reduced risk of lung cancer. Finland's Dr. Knekt and colleagues had drawn the same conclusion in a report published in the American Journal of Epidemiology, published in August 1997.

The U.S. Apple Association (USApple) is the national trade association representing all segments of the apple industry. Members include 40 state and regional apple associations representing the nation's 9,000 apple growers, as well as 450 individual firms involved in the apple business. USApple's mission is to provide the means for all segments of the U.S. apple industry to join in appropriate collective efforts to profitably produce and market apples and apple products.