An apple a day keeps the doctor away? Here's what the science says

"An apple a day keeps the doctor away."

Few proverbs about food have spread as widely around the world. The saying may be a slight exaggeration, but most medical experts agree it is not entirely without scientific basis.

What makes the adage particularly interesting is that it has actually been put to a scientific test — and held up, at least in part. A research team at the University of Michigan School of Nursing published findings in JAMA Internal Medicine in 2015, applying rigorous epidemiological methods to verify a piece of folk wisdom.

The researchers divided 8,728 adults into two groups — those who ate at least one apple a day and those who ate none — and asked whether they had visited a doctor or taken prescription medication over the previous year. Only whole, fresh apples counted; apple juice and applesauce were excluded.

The results showed no statistically significant link between daily apple consumption and doctor visits. However, prescription drug use told a different story: apple eaters were statistically less likely to take prescription medications than non-apple eaters.

"Evidence does not support that an apple a day keeps the doctor away," the researchers wrote, "but the small fraction of US adults who eat an apple a day do appear to use fewer prescription medications."

Where did the saying come from? It originated in 19th-century Wales and was first recorded in the British journal Notes and Queries in 1866 as a Welsh regional proverb. The original wording was: "Eat an apple on going to bed, and you'll keep the doctor from earning his bread." The version familiar today was fixed in 1913, when British linguist Elizabeth Wright included it in her collection of English dialects and folklore.

Apples likely became the fruit of choice partly because they were widely grown and commonly eaten in Wales at the time. But the apple's well-documented health benefits are considered the more fundamental reason. Those benefits have been recognized across cultures for centuries and, in modern times, confirmed through scientific research.

Researchers at Ohio State University found that eating one apple a day may help reduce levels of LDL — so-called "bad" cholesterol — in middle-aged adults, according to a study published in the Journal of Functional Foods in 2012.

A study by researchers at the University of Oxford estimated that if 70 percent of British adults over 50 ate one apple a day, about 8,500 cardiovascular deaths could be prevented annually. The figure was a theoretical projection combining existing clinical research.

A Chinese review published in Food Science & Nutrition in 2023, which synthesized a decade of literature, concluded that apple consumption has a positive effect on preventing cardiovascular disease, cancer and cognitive decline, as well as on skin health.

According to Harvard T.H. Chan School of Public Health, the two key compounds behind these benefits are quercetin and pectin — an antioxidant and a dietary fiber, respectively, both found in abundance in apples.

Quercetin is a flavonoid with anti-aging and anti-inflammatory properties. Pectin is a soluble fiber that helps prevent constipation and lower LDL cholesterol levels. It is also fermented by beneficial bacteria in the colon, producing compounds that may help protect against certain cancers and intestinal diseases.

There is, however, one condition for getting the most out of an apple: eat it whole, skin and all. Most of the fiber and antioxidants are concentrated in the peel. Removing it cuts fiber content by nearly half — 46 percent, according to US Department of Agriculture data.

Juicing apples eliminates nearly all the dietary fiber, causes blood sugar to rise more quickly and reduces the feeling of fullness.