An apple a day keeps the doctor away — or so the conventional wisdom has it. However, the old proverb hasn't stood up well to a rigorous scientific study, researchers say.

A study at the University of Michigan School of Nursing in Ann Arbor found that the saying, which has been around since at least the 1800s, may be just that — a saying, nothing more.

"Everybody thinks of the apple as a healthy food, and it is, but after adjusting for other variables we didn't find a difference in doctor visits between apple eaters and non-apple eaters," said study leader Matthew Davis.

The researchers analyzed data from around 8,400 adults in the U.S. who responded to questionnaires from the National Health and Nutrition Examination Survey from 2007 to 2010.

Initial numbers that suggested apple eaters made fewer visits to health care providers proved statistically insignificant when adjusted for socioeconomic factors and additional health parameters, the researchers report in JAMA Internal Medicine.

One surprise of the study was that while apples apparently won't keep the doctor away, they may have people making fewer trips to their local pharmacy; there was a statistically significant finding that apple eaters tend to take fewer prescription drugs.

However, while apple consumption has been linked to a reduction in the risk of several types of cancer, asthma and cardiovascular disease, and may provide benefits for diabetes, bone health and even Alzheimer's disease, they're not a cure-all guaranteed to keep you out of your doctor's office, experts say.

"Eating an apple a day is unlikely to undo the ill effects of the typical 'Western diet' that is high in red and processed meat, junk food and fast food and low in plant foods," says Samantha Heller, a nutritionist at NYU Langone Medical Center.

The researchers say they estimate 19.3 million adults in the U.S. are regular consumers of apples, to the tune of around 8.8 million pounds of apples a day — whether it keeps the doctor away or not.

Turning the full power of scientific research on an old proverb may seem slightly frivolous, and JAMA Internal Medicine did accompany the published article with an editorial note that it was part of the journal's "first April Fool's issue."

Still, journal editor Rita Redberg says she "did not ask the readers to discount the findings," and that the paper was published to demonstrate that "a study could be scientifically rigorous and still have some humor or light side, as this one did."

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