There are some health "facts" that many people have heard so many times that they just assume they are true, ideas like "juice is healthy" or "gum will stay in your stomach for years.
But many of these "facts" are really myths about health.
Here's what the science really says about these health myths.
There's something about health and nutrition folk wisdom that's resistant to truth.
Common health "facts" include the ideas that MSG will make you sick, that a juice detox is just what you need after a week of indulgence, and that sports drinks like Gatorade are totally fine since you need the electrolytes.
None of these things are true. They, like many other folk sayings and tips, fall into the category of health myths that are totally — or at least mostly — wrong.
Here's the truth behind some of those health claims you've heard all your life, but might not hold water at all.
MSG in Chinese food will make you sick.
The myth that MSG is bad for you comes from a letter a doctor wrote to the New England Journal of Medicine in 1968, where he coined the term "Chinese restaurant syndrome" to describe a variety of symptoms including numbness and general weakness.
But though the doctor blamed these feelings on monosodium glutamate, MSG, the research doesn't back it up. The scientific consensus according the American Chemical Society is that "MSG can temporarily affect a select few when consumed in huge quantities on an empty stomach, but it's perfectly safe for the vast majority of people."
And this makes sense — MSG is nothing more than a common amino acid with a sodium atom added. The placebo effect is more than strong enough to account for the negative effects sometimes associated with MSG.
Coffee stunts your growth.
There isn't a whole lot of evidence on this, but most research finds no correlation between caffeine consumption and bone growth in kids.
In adults, researchers have seen that increased caffeine consumption can very slightly limit calcium absorption, but the impact is so small that a tablespoon of milk will more than adequately offset the effects of a cup of coffee.
Interestingly, advertising seems to be largely responsible for this myth. A breakfast cereal manufacturer named C.W. Post was trying to market a morning beverage called "Postum" as an alternative to coffee, so he ran ads on the "evils" of Americans' favorite hot beverage, calling it a "nerve poison" that should never be served to children.
Bundle up or you’ll catch a cold.
Being physically cold isn't what gets you sick; exposure to a cold virus does. There's no evidence that going outside with wet hair when it's freezing will make you sick by itself — provided you avoid hypothermia.
But there are some scientifically sound explanations for why people catch more colds in winter. Because we spend more time in close quarters indoors, it is more likely that we'll cross paths with a cold-causing virus spread from another person during the winter. And for several reasons, we may have a harder time fighting off cold and flu virus particles in winter.
But being cold itself isn't what makes sick, and some argue that cold exposure can actually improve your health.
The chemical tryptophan in turkey makes you sleepy.
Who doesn't love the post-Thanksgiving nap? We frequently consider those naps inevitable, since turkey contains tryptophan, an amino acid that is a component of some of the brain chemicals that help you relax.
But plenty of foods contain tryptophan. Cheddar cheese has even more than turkey — and cheddar is never pointed out as a sleep inducing food. Experts say that instead, the carbs, alcohol, and general size of the Turkey-day feast are the cause of those delicious holiday siestas.