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Medical Superstitions: Myths versus Facts

Does an apple a day really keep the doctor away? Can cracking your knuckles give you arthritis? Is there any truth to feeding a cold and starving a fever? Some of these sayings go back hundreds of years, and factual or not, they continue to live on.

Gregory Maddox, MD, with Overlake Clinics Primary Care Newcastle, addresses five popular medical superstitions, separates the myths from the facts and provides sound advice on what you can take away from each one. 

An Apple a Day Keeps the Doctor Away

There may some truth here. This saying is more a comparison between apple eaters versus non-apple eaters. The largest study looking at this aphorism was from 2015 in the U.S. and showed a small decrease in doctors’ visits and prescription medications in apple eaters compared to non-apple eaters. There are quite a few limitations to this study, but it’s mostly stating the obvious. Apple eaters are more likely to be healthy eaters with fewer lifestyle risk factors than non-apple eaters. So, why not? Eat an apple a day, in addition to multiple servings of other fruits and vegetables. 

Interestingly, this saying comes from a Welsh proverb from approximately 150 years ago, “Eat an apple on going to bed and you'll keep the doctor from earning his bread.”

Starve a Fever, Feed a Cold. Or, Feed a Fever, Starve a Cold?

Which one is it? Either way, the overall medical consensus and research suggests that staying well hydrated and getting plenty of rest is the most effective way to recover quickly from either a viral or bacterial infection. If you feel like eating, great. Will it make your flu go away quicker? Probably not. 

Conversely, fasting to treat a fever is a bad idea. Supplements, vitamins, chicken soup and plenty of other interventions have been researched extensively for common colds, flu and now COVID-19. Any positive effects from these are small at best. The best advice is to hydrate, rest and eventually your immune system gets the upper hand—usually in 5-10 days. 

This saying was first published in a 1570s dictionary, but it stems from the middle ages. It was thought that there are two types of illnesses: colds that need to be fueled (eating) and fevers that need to be cooled (fasting).

Cracking Your Knuckles Causes Arthritis

Knuckle cracking is thought to be caused by physically increasing the joint space followed by a rapid collapse of gas bubbles within the joint. The largest study looking at this showed that knuckle cracking is not associated with long-term joint arthritis. Another small study later confirmed that chronic knuckle popping is not associated with long-term joint arthritis. Interestingly, this study did show that it may be associated with a slight decrease in grip strength and a small amount of hand swelling compared to non-knuckle poppers. This was a narrow study, and general expert consensus is that while knuckle popping may be annoying to some, it is unlikely harmful.

Catch a Chill and You’ll Catch a Cold

In general, being cold or wet will not cause you to become sick. You need to have direct viral exposure to develop cold-like symptoms. That said, there is some logic to this saying. Viral pathogens are more prevalent during colder months, and we tend to spend more times indoors, which promotes viral spread.

Additionally, there are studies correlating low Vitamin D levels and decreased sun exposure with a higher incidence of viral upper respiratory symptoms . This is certainly relevant to us in the Pacific Northwest during the cold winter months.

Long story short, you need to come into direct contact with a virus in order to develop cold symptoms. While this is more likely to happen in colder months due to more viruses being prevalent in the community, this is not directly related to being exposed to lower temperatures. 

Sitting Too Close to the TV Will Harm Your Eyes

While sitting too close to a TV or monitor might cause eyestrain and a headache, it will not cause long-term harm to your eyes or vision. Additionally, the FDA notes that all LCD and plasma screens are not capable of emitting x-radiation. We still strongly recommend limiting/monitoring screen time, especially among children, which is associated with a multitude of health benefits including social and emotional development, cardiovascular health, mental well-being and more. 

Always be sure to consult with your healthcare provider for medical advice.


Davis MA, Bynum JPW, Sirovich BE. Association Between Apple Consumption and Physician Visits: Appealing the Conventional Wisdom That an Apple a Day Keeps the Doctor Away. JAMA Intern Med. 2015;175(5):777–783. doi:10.1001/jamainternmed.2014.5466  

Sexton D, McClain M. The common cold in adults: Treatment and prevention. Up-To-Date. Literature review current through: Mar 2022. | This topic last updated: Mar 24, 2022.

Swezey RL, Swezey SE: The consequences of habitual knuckle cracking. West J Med 122:377-379, May 1975

Castellanos J, Axelrod D. Effect of habitual knuckle cracking on hand function. Annals of the Rheumatic Diseases 1990; 49: 308-309

Lee GM, Friedman JF, Ross-Degnan D, Hibberd PL, Goldmann DA. Misconceptions about colds and predictors of health service utilization. Pediatrics. 2003 Feb;111(2):231-6. doi: 10.1542/peds.111.2.231. PMID: 12563044.

American Academy of Ophthalmology and Seattle Children’s Research Institute.

Television Radiation | FDA

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