Should apple growers follow the lead set by berries and fruits like tart cherries and use health ­benefits as a way to sell more apples?

That might be a useful strategy, says Dr. Dianne Hyson, the department chair in family and consumer science at California State University in Sacramento and a registered dietitian. She spoke to about 300 people in the apple industry during the U.S. Apple ­Association’s outlook and marketing conference in Chicago.

She reviewed the growing body of scientific literature about the health benefits of apples. The old saying, “an apple a day keeps the doctor away,” is well on the path moving from old wives’ tale to scientific fact, she said.

People have always wanted a magic pill that would confer wonderful health benefits, she said. That has spawned enormous numbers of studies, especially in the last ten years, on the components of foods and what they do to harm or improve health. Many people would like to see those beneficial components extracted and made available as pills in a bottle.

“People will pay $20 for a magic extract,” she said. “We need to stick with the message that whole foods is where it’s at.” An apple is a pretty good pill, and really not all that much bigger, and costs less than a dollar. Apple juice is good as well, although it lacks the fiber of a whole apple.

In health studies, it is very difficult to prove cause and effect, she said. It’s difficult to do controlled studies on people, so most researchers try to establish links between health and some food or behavior using basic survey techniques. Once they find an association, they search for components in the food that might be the active ones, and then they move into controlled animal feeding ­studies to try to establish cause and effect.

For apples, that process is just beginning, she said.

Apples contain five classes of phytochemicals, called polyphenols, which are technically not nutrients but do appear to promote health. These healthful benefits might come by affecting processes like oxidation that leads to cell damage, proliferation that leads to cancer, inflammation, adhesion and aggregation that affect blood clotting and plaque formation in arteries, and apoptosis, a general term describing the ongoing “programmed” death of cells. Every day, some 50 to 70 billion cells die in the ­average human adult body, and most are replaced.

In studies, apples have been linked to antioxidant protection; reduction in cell damage and proliferation in colon and breast cancer; reductions in cardiovascular disease, asthma, diabetes, and inflammation; and improvement in bone health, gastrointestinal tract health, weight, and cognition (mental acuity).

There is some distance between an association and providing conclusive proof, and along the way there is lots of information and misinformation about the health benefits of various foods, Hyson said. But more proof is on the way. And while we’re waiting, eating an apple a day seems like good advice.