We've all heard old wives' tales -- half-remembered bits of folklore, quack medicine and superstition passed on as the gospel truth. And while thinking that a broken mirror creates bad luck might seem preposterous (surely, we tell ourselves, no one actually believes that sort of thing), some old wives' tales are amazingly persistent and continue to hold credence with a surprising number of us. You might even have thought one or two tales were true yourself!
Carrots improve your sight
Many people think that eating carrots, or other foods rich in beta-carotene, will improve their ability to see in the dark. In fact, there is no medical evidence to support this belief. The idea may originate in World War II propaganda: The British government claimed the keen night vision of its fighter pilots was the result of eating carrots. In fact, it was merely disinformation intended to prevent the German intelligence services from discovering the British had mounted radar sets in some of their aircraft.
Toads give you warts
If you look at a toad's bumpy skin, it's easy to see how people might believe that touching one would give them warts. The bumps on a toad, however, are not warts. They're simply a characteristic of the toad's skin. The warts that people get are caused by a virus -- specifically a human virus -- and are not transmitted by toads.
Too much telly hurts your eyes
Most people remember being warned by their parents that too much television would hurt their eyes. But in truth, there is no known link between watching television and permanent eye damage. Staring at a screen for too long can cause temporary eye fatigue, however, which might be how this old wives' tale started.
Mummy's belly indicates the sex of the baby
Even today many people believe that the way a pregnant woman carries her baby can predict the child's sex. If the mother's tummy is more pronounced at the top, the belief goes, the child will be a girl, whereas if the mother is "carrying low" it will be a boy. Actually, though, there is no connection between the mother's belly shape and the child's gender. It's the individual structure of the mother's body that determines the shape of her abdomen during pregnancy, not the child's sex.
Related: 10 Foods for increased fertility
You shouldn't swim after eating
Children eager to splash into the sea or a swimming pool are often warned that if they go swimming within a half-hour or an hour after eating, they'll get cramps. In fact, there's no known correlation between eating before swimming and getting cramps. The body is perfectly capable of digesting and swimming at the same time.
You'll catch a cold if you go outside with wet hair
An old conviction states that a person who goes outside with wet hair will catch a cold. But in reality, damp hair has nothing to do with whether you catch a cold or not. Like warts, colds are the result of viral infections. Contact with other infected people is the root cause, not wet hair.
Shaving your legs makes the hair grow back thicker
Shaving your legs doesn't make the hair on them grow back more heavily. If that were the case, men, who tend to shave their faces daily, would all have impenetrable beards of incredible proportions. This belief probably originates from the fact that a razor typically cuts hair at the thickest part, making the trimmed hair seem larger. New hair growing against shaved skin also stands out more because of the contrast.
Related: Beauty myths people still believe in
Feed a cold, starve a fever
Many fever sufferers have diminished appetites when they're unwell, but that doesn't mean they actually ought to be eating less. People suffering from either a fever or a cold need a healthy, balanced diet with plenty of fluids. There is some evidence, notably a 2002 study from the Academic Medical Center in Amsterdam, that indicates fasting may stimulate an immune response in some fevers, but the data is not sufficient enough to conclude fever patients should ever be starved.
Related: Must-have cold weather products
Cracking your knuckles causes arthritis
Crack your knuckles in public and you can be certain some busybody will warn you that cracking your knuckles causes arthritis. The good news is it doesn't. The bad news is habitually cracking your knuckles over many years may cause a reduction in grip strength and flexibility, according to rheumatologist Dimitrios Pappas on the John Hopkins Arthritis Center website. It may not be arthritis, but it's a good reason to avoid it.
Related: How to diagnose arthritis in fingers
Cats choke babies
Cats have always had bad press in folklore, often presented as malevolent tricksters. An old wives' tale holds that cats will suck the breath out of the mouths of newborn babies. Another version of the tale claims that cats will sleep on babies' faces, smothering them. The first is impossible, and the second is highly unlikely. Nonetheless, the RSPCA recommends that pets of any kind always be supervised around small children. This is so children, who don't understand the consequences of their actions, won't harm or frighten pets or be bitten or scratched.
Related: 9 Weird pets for kids