In 1866, the proverbial recommendation for eating an apple a day first appeared in print. A medical journal used the excuse of April Fool's Day almost 150 years later to publish a study that asks, seriously, if this wisdom really holds the doctor away.
The study tells us that the aphorism "an apple a day keeps the doctor away" was invented in 1913 but was based on the original form of a different rhyme, in Wales some 149 years ago: "Eat an apple when you go to bed and you will keep the doctor from making his bread," went the Pembrokeshire proverb.
The University of Michigan School of Nursing researchers in Ann Arbor believe that giving an empirical evaluation of such medical proverbs "may allow us to benefit from the wisdom of our predecessors."
Matthew Davis, PhD, and co-authors measured the outcome of no more than one visit to the doctor a year as a means of investigating the effectiveness of the proverb in regular apple eaters relative to non-apple eaters for the study's measure of holding the doctor away.
So did a regular apple manage to keep the doctor away from it? No it hasn't. In the study, there was no statistically significant difference in doctor visits for frequent apple eaters. The study found, however, that an apple a day kept the pharmacist away.
'Prevent the utilization of health care facilities'
When socio-demographic and health-related characteristics such as education and smoking were taken into consideration, frequent apple eating was not correlated with a limit of one self-reported doctor visit per year being successfully maintained.
Of the 8,399 respondents who replied to a questionnaire to remember their dietary diets, 9% (753) were apple eaters and 7,646 were non-apple eaters, the remainder.
The apple eaters displayed greater academic achievement, were more likely to be from a racial or ethnic group, and were less likely to smoke. The National Health and Nutrition Review Survey conducted between 2007-08 and 2009-10 provided the data for the study.
"While the direction of the associations we observed supports the superiority of apple eaters over non-apple eaters in preventing the use of health care services, these differences lacked statistical significance to a large extent," say the authors after accounting for the differences in apple eaters that may have clarified why they used health care services beyond the effects of apple eating itself.
An apple a day means one with a diameter of at least 7 cm.
The researchers compared frequent apple eaters with non-apple eaters to analyze apple eating against visits to the doctor. If the participants responded that they had at least 149 g of raw apple, an apple a day would count.
Eating less than this amount was counted as not eating an apple every day and consumption of apples dependent solely on juices or sauces was also omitted. By comparing the doctor visits of people who did not eat apples with those who ate one small apple, one medium apple or one large apple a day the research also searched for some answer to increasing the amount of daily apple-eating.
The study indicates no correlation between the "dose" of apple and the probability of holding the doctor away in terms of avoiding health care services." Except for the avoidance of prescription drugs, the authors found.
The study found that apple eaters were more likely to keep the doctor away, but 39.0 percent of apple eaters skipped more than one annual doctor visit, compared with 33.9 percent of non-apple eaters, before controlling for the socio-demographic and health characteristics of the survey respondents.
The everyday apple eaters were also more likely to stop the use of prescription drugs effectively (47.7 percent versus 41.8 percent)-and statistical research survived this gap.
Therefore the link between consuming an apple a day and keeping the pharmacist away was a statistically relevant finding, while keeping the doctor away was not valid.
There was no difference for apple eaters in the probability of keeping one of these two away, nor did the proverb display any impact in a study of overnight hospital stays or mental health visits.
The ultimate conclusion of this research was that the long-standing wisdom was validated by only one observation. "Apple eaters "were far more likely than non-apple eaters to stop prescription drug use.
In their final report, the authors say that the promotion of apple consumption can only have a 'small benefit in reducing national expenditure on health care, adding: