7 Medical Myths Busted

This image is no longer available

Fact or fiction? Even some doctors are duped by these common medical myths.

Apparently some health-related myths are so prevalent that even many doctors believe them to be true. According to a report in the British Medical Journal, here are 7 popular medical myths that are either unsupported by evidence or simply untrue.

Medical myths busted

The myth: You should drink at least 8 glasses of water per day.

The fact: While references from 1945 suggest staying hydrated in this way, the authors say this recommendation is completely unsupported by evidence. Studies suggest that adequate fluid intake is usually met through typical daily consumption of juice, milk, and even caffeinated drinks. (In fact, drinking excess amounts of water can be dangerous, researchers say, resulting in water intoxication, hyponatraemia, and even death.)

The myth: We use only about 10 per cent of our brains.

The fact: This myth has persisted for over a century, despite dramatic advances in neuroscience. MRI scans and other imaging studies show no dormant areas of the brain, and even viewing individual neurons or cells reveals no completely inactive or silent areas, the report says. It is thought this myth started as early as 1907, by people advocating ‘the power of self improvement’ and tapping into a person’s unrealized potential. (Some sources attribute this claim to Albert Einstein, but no such reference or statement by Einstein has ever been recorded, the authors say.)

The myth: Reading in dim light ruins your eyesight.

The fact:While dim light can certainly cause eye strain –- as well as uncomfortable side effects such as dryness and difficulty focusing — there is no evidence it causes permanent eye damage. Instead, symptoms of eye strain generally subside after resting.

The myth: Hair and fingernails continue to grow after death.

The fact: This myth does have a basis in a biological phenomenon that can occur after death: dehydration of a deceased body can cause the skin around the hair or nails to retract. This contrast can create an appearance of increased length, but the actual growth of hair and nails requires a complex hormonal regulation not sustained after death, the authors say.

The myth: Eating turkey makes you sleepy.

The fact: While turkey does contain tryptophan – which scientific evidence shows can cause drowsiness – it doesn’t contain any more of it than beef or chicken. And, in fact, other sources of protein, such as pork or cheese, contain more tryptophan per gram than turkey. So why does turkey get such a bad rap? Because it is often the star of a huge holiday feast, researchers say, and is accompanied by stuffing, vegetables, desserts and wine, all of which can make you feel sleepy.

The myth: Shaving causes your hair to grow back faster, darker or thicker.

The fact: As far back as 1928, a clinical trial showed that shaving had no effect on the thickness or rate of hair growth. (And more recent studies have confirmed these findings.) But because shaved hair is blunt, and doesn’t have the finer taper at the ends, it can look to be coarser. New hair can also appear darker, but this can be because it hasn’t yet been bleached by the sun.

The myth: Mobile phones are dangerous in hospitals.

The fact: Following reports of suspected electromagnetic interference with medical devices, hospitals widely banned cell phone use. The study’s authors, however, found no evidence of death caused by use of cell phones in hospitals. While less serious incidents, including false alarms or incorrect reading on monitors, have occasionally been reported, subsequent studies (at both the Mayo Clinic and in Europe) indicate little or no interference. And a large survey of doctors suggests that use of mobile phones reduces risk of medical error or injury resulting from delays in communication.

Read the British Medical Journal Report