"An apple a day keeps the doctor away" is a common English-language

proverb A proverb (from ) or an adage is a simple, traditional saying that expresses a perceived truth based on common sense or experience. Proverbs are often metaphorical and are an example of formulaic speech, formulaic language. A proverbial phrase ...

that appeared in the 19th century, advocating for the consumption of apples, and by extension, "if one eats healthful foods, one will remain in good health and will not need to see the doctor often."

Origin

A variant of the proverb, "Eat an apple on going to bed, and you'll keep the doctor from earning his bread" was recorded as a

Pembrokeshire Pembrokeshire ( ; ) is a Principal areas of Wales, county in the South West Wales, south-west of Wales. It is bordered by Carmarthenshire to the east, Ceredigion to the northeast, and otherwise by the sea. Haverfordwest is the largest town and ...

saying in 1866. The modern phrasing, "An apple a day keeps the doctor away", began usage at the end of the 19th century, with early print examples found as early as 1887.

Scientific background

A 2013 study using

computer modelling Computer simulation is the running of a mathematical model on a computer, the model being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determin ...

compared eating apples with taking a common daily cholesterol-lowering drug to estimate risk of

cardiovascular diseases Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheuma ...

. The computer model estimated that eating an apple a day was generally comparable for people over age 50 years to using a statin drug to reduce

low-density lipoprotein cholesterol Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall densit ...

, concluding that eating an apple a day "is able to match modern medicine and is likely to have fewer side effects," while having similar annual cost. A 2015 study found apple eaters "were more likely, in the crude analysis, to keep the doctor (and prescription medications) away." When they adjusted for "sociodemographic and health-related characteristics, however, the association was no longer statistically significant". The study also found that people who ate an apple a day used fewer

prescription medication A prescription drug (also prescription medication, prescription medicine or prescription-only medication) is a pharmaceutical drug that is permitted to be dispensed only to those with a medical prescription. In contrast, over-the-counter drugs ca ...

Nutritional content of an apple

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

-standard medium-size (100 gram) raw apple is 86% water and 14%

carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...

s with negligible content of fat and

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

, and supplies 52

calorie The calorie is a unit of energy that originated from the caloric theory of heat. The large calorie, food calorie, dietary calorie, kilocalorie, or kilogram calorie is defined as the amount of heat needed to raise the temperature of one liter o ...

s of

food energy Food energy is chemical energy that animals and humans derive from food to sustain their metabolism and muscular activity. Most animals derive most of their energy from aerobic respiration, namely combining the carbohydrates, fats, and protein ...

. It contains a moderate amount of

dietary fiber Dietary fiber (fibre in English in the Commonwealth of Nations, Commonwealth English) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical co ...

, but otherwise has a low level of

micronutrient Micronutrients are essential chemicals required by organisms in small quantities to perform various biogeochemical processes and regulate physiological functions of cells and organs. By enabling these processes, micronutrients support the heal ...

References

{{Wiktionary 1880s neologisms 1880s quotations Apples English proverbs Health effects of food and nutrition Metaphors referring to food and drink