Medical Myths – and Why We Believe Them

by DavalosMcCormack on December 26, 2007

Centuries ago doctors used to “bleed” patients, thinking that by getting rid of the bad blood they would get rid of the disease. Nowadays we like to think we’ve advanced a bit, but a new study says many doctors still subscribe to medical myths that have no more basis in science than “bleeding”.

The study, in the British Medical Journal, is called “Medical Myths Even Doctors Believe”. They looked at a variety of myths including the ones that you need to drink at least 8 glasses of water a day; that your finger nails keep growing after you are dead; that people only use 10 percent of their brains; and eating turkey makes you sleepy.

Turns out, when the researchers reviewed the medical literature they found that all of them are either unproven, or just simply not true!

Let’s take the water one first. The researchers traced back this idea of needing to drink at least eight 8oz glasses of water a day to 1945, when the British Government’s Nutrition Council made the recommendation. But one of the key elements of that recommendation was that a lot of fluid found in fruits and vegetables, as well as tea and coffee, should count towards that 64 ounce total. Nowadays no one mentions that so you are left feeling you need to drink 8 glasses of water. But there is one side benefit. All that extra water means you get more exercise, walking to and from the bathroom.

How about the idea we use only 10 percent of our brains! Blame Jerry Seinfeld. It’s true, along with “yadda yadda yadda” and “master of your domain” Seinfeld is credited with helping spread this idea. It’s thought to have begun in the early 20th century with self-help folks who wanted to convince people they hadn’t reached their full potential. But thanks to shows like Seinfeld it got a lot more exposure towards the end of the century. However, MRIs and PET scans and other brain imaging devices show it’s just not true. They show we use all our brain. We may not use it as wisely as we could, but that’s a whole different matter.

Now, what about your finger nails and hair continuing to grow after you die. It’s a spooky idea, a favorite in horror movies. The only problem is it’s just not true. Sorry. The researchers say after we die our skin begins to dry out and contract. The hair and nails stay the same but look as if they’re longer because of the shrinking skin.

As for other myths:
•    Reading in dim light is bad for your eyes. No, it’s not. It may cause temporary discomfort if you do it for a long time, but the eyes quickly recover.
•    Eating turkey makes you sleepy. Tryptophan does make you sleepy, but there is no more tryptophan in turkey than in chicken, and a lot less than in Swiss cheese. Maybe it’s just because you ate such a huge meal along with the turkey that you’re tired.
•    Shaving makes hair thicker and coarser. No. It’s another optical illusion. When hair grows back after shaving the top is blunt, that makes it appear thicker than other hairs with tapered points.

So, next time you go to your doctor, just remember she or he is not such a smarty pants after all.

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