MEDICAL MATTERS:Myths have been around for so long that they're almost part of medicine itself
LET'S START this week with a quiz. Please rate the following statements as true or false (answers at the end of the column).
1. Cotton buds are good for clearing ear wax.
2. Cracking your knuckles does not cause arthritis.
3. Toilet seats are a source of sexually transmitted disease.
4. You cannot catch cold by going outside with wet hair.
5. Mobile phones are dangerous in hospitals.
6. We use only 10 per cent of our brains.
7. Meals rich in protein or carbohydrate can make you drowsy.
8. It's dangerous to swim after eating.
9. Shaving makes hair grow back faster.
10. You must drink at least eight glasses of water a day.
I put together these statements from well-known medical myths and old wives tales. It's amazing how we automatically accept the veracity of these sayings purely on the basis of hearing them repeated again and again.
I have written previously about how I told my children when they were younger not to read in poor light on the basis that it would damage their eyesight. Well, I was wrong. There is a multitude of evidence to show that poor light does not hurt our eyes.
"Drink at least eight glasses of water a day" sounds right. Water is good for you, and didn't you read somewhere that with our modern pace of life, we do not drink enough? Wrong. Apparently the origins of the myth go back to a 1945 recommendation advocating the intake of 2.5 litres of water a day. Crucially, however, the sentence: "Most of this quantity is contained in prepared foods" seems to have been ignored. There is now a number of studies showing that we take enough fluids in a typical daily consumption of juice, milk and caffeinated drinks.
Mobile phones are not a danger to hospital patients. This chestnut ties in with the dire warnings dished out by airline cabin crew during safety demonstrations. And the more recent admonition that putting phones to "flight" mode is unsafe adds to the fear. The medical literature contains no cases of death caused by the use of a mobile phone in a healthcare facility.
Alarms or monitoring systems have been triggered and incorrect readings on heart monitors reported, but no life-threatening incidents have emerged. Rigorous testing found only minimal electromagnetic interference by phones, but only at distances of less than a metre.
A 2007 study found no interference in 300 tests of mobile devices in hospital treatment rooms. I suspect most doctors carry and use their mobiles while working in hospitals - would healthcare institutions tolerate this if there was a real risk to patients?
Do you suffer with waxy ears? Cotton buds are ideal for cleaning ears. There is just one problem. The bud simply pushes wax further into the ear canal, where it piles up causing deafness. Wax-softening drops are a better option, and if this doesn't work, a regular visit for professional ear washing should do the trick.
Does shaving make hair grow back faster and coarser? This is a really stubborn myth: a study carried out 80 years ago disproved it. Shaving removes the dead part of hair and not the living section below the skin's surface, so it has no effect on the speed of regrowth. New hair looks darker because it hasn't been exposed to the sun or chemicals for very long. Lacking wear and tear, it is less tapered than older hair, making it appear coarser.
The belief that we use only 10 per cent of our brains can be traced back to 1907. It seems to have coincided with a popular drive at the time for self-improvement, and the urge to tap into people's unrealised abilities.
However, now that we have reliable methods of brain imaging, we can say with certainty that no area of the brain remains completely inactive. Studies of patients with brain injury show that damage to different areas is associated with specific disabilities, reflecting the localisation of different brain functions.
Did you spot the three true statements? Cracking your knuckles may annoy those around you, but it certainly won't lead to arthritis in later life. Meals rich in protein and carbohydrate can make you drowsy, although whether they do depends on the volume of food eaten. A large meal can reduce blood flow to the brain, leading to sleepiness.
And, despite what thousands of mothers have told their offspring through the ages, you cannot develop the common cold by going out while your hair is wet.
(Answers: 1F, 2T, 3F, 4T, 5F, 6F, 7T, 8F, 9F, 10F)