Health myths

Knuckle-cracking does not cause arthritis, and other health myths

Green mucous doesn’t indicate a sinus infection, milk doesn’t make you phlegmy and cracking your knuckles will not cause arthritis. So say doctors Aaron E. Carroll and Rachel C. Vreeman, authors of the book Don’t Swallow Your Gum!: Myths, Half-truths, and Outright Lies About Your Body and Health.

Here are a few of the other myths covered in the book:

Cold weather gives you a cold: The rise of colds during the winter is likely due to people spending more time indoors, where germs are more likely to be transmitted.

Body heat is lost through your head: Heat is equally lost through any exposed body part.

Double-dipping is OK: A group of scientists conducted an experiment with bitten crackers dipped in salsa, cheese dip, chocolate syrup and water, then measured the amounts of bacteria in the dips and volunteers’ mouths. Three to six dips transferred 10,000 bacteria from the mouth to the dip. Salsa was the dirtiest dip.

The three-second rule: Scientists testing this pervasive myth have found food that falls onto wood or tile floors picks up large amounts of bacteria the moment it makes contact. Surprisingly, fewer germs are picked up when food hits carpet.