WISDOM that’s passed down through the ages can often result in the original nugget of truth beinfoing vulnerable to distortion, like a very long-winded game of Chinese whispers.
Case in point: Most of your body heat isn’t actually lost through your head, and cracking your knuckles doesn’t cause arthritis — but there’s a fair chance you’ve been told otherwise.
The latest health belief to be deemed an old wives’ tale by the medical world is that cranberry juice can prevent urinary tract infections (UTIs).
The theory was that cranberries make our urine more acidic, creating an environment in which bacteria struggles to live. A 2010 study in the journal Archives of Internal Medicine did find that people who used cranberry products were 38 per cent less likely to develop UTIs.
However, experts at the UK’s National Institute for Health and Care Excellence recently announced that the evidence isn’t strong enough to support the claim.
While cranberry juice won’t do any harm, they said there’s “no evidence” it can remove the infection. Instead, they advise drinking lots of water, taking painkillers and seeking advice from a GP, who may prescribe antibiotics.
With this medical revelation in mind, we look into other popular health sayings and ask: Are they old wives’ tales or is there, in fact, science behind these statements?
CARROTS ARE GOOD FOR YOUR EYES
THE claim is said to have its origins in World War II, when it was popularised by a British propaganda campaign, but there’s some truth to it. Carrots are a rich source of beta carotene, which the body converts into a type of vitamin A that helps maintain good vision. However, before you reach for the carrots, consider this:
Unless you’re deficient in vitamin A, having more beta carotene won’t help you see better. This is because when your body has enough of this antioxidant, it stops converting it into vitamin A.
MOST BODY HEAT IS LOST THROUGH YOUR HEAD
IN THE old days, before central heating and reverse-cycle airconditioning, people would wear a hat to bed because their head was the only body part not under the blankets.
However, the theory that most of your body heat is lost through your head was debunked in 2008 by a team at the University of Indiana in the US.
What is true is that your face, head and chest feel temperature changes more acutely than elsewhere on your body, so if you cover them up, you don’t feel as cold. In truth, heat loss from your head is now thought to be proportional to the rest of your body.
SITTING TOO CLOSE TO THE TV IS BAD FOR YOUR EYES
IN 1967, US television manufacturers General Electric warned customers that some of their TV sets were emitting harmful X-rays and told children to keep a safe distance, resulting in the infomon belief that sitting too close to the box would damage your eyesight.
However, subsequent TVs were built with fewer rays, and today, LCD and plasma screens contain none.
You can still strain your eyes if you stare at a screen for too long, but the same can be said of anything that requires focusing up close, such as reading a book or staring at a tablet.
Dr Lee Duffner of the American Academy of Ophthalmology isn’t concerned, maintaining that watching TV screens close-up or otherwise “won’t cause any physical damage to your eyes”.
KNUCKLE CRACKING CAUSES ARTHRITIS
THIS saying was probably created to stop someone’s annoying habit, but there’s no evidence that cracking your knuckles results in arthritis. So say experts at Harvard Medical School in the US, who reviewed studies infoparing rates of arthritis among those who do and don’t do it. The sound occurs when gas bubbles form in the fluids between your joints and are released by a sudden movement.
It’s not thought to be harmful and doesn’t mean you have a functional issue with your knuckles — or any other joint that makes the sound.
BEING COLD GIVES YOU A COLD
YOUR parents probably used this saying to convince you to wear a coat as a child, but it turns out that living in the Arctic makes you no more likely to catch a chill than living in Australia. In fact, the cold may stimulate the immune system, studies show.
The myth likely stems from a time when fevers couldn’t be treated, so temperatures were used by way of explanation. However, there is a correlation between cold weather and colds, according to research published in the journal Critical Care. If your body’s core temperature gets too low, you can end up with hypothermia, which lowers your immunity and make you more susceptible to viruses. So the cold can indirectly lead to a cold, but it doesn’t cause it.
GUM TAKES SEVEN YEARS TO DIGEST
THIS was another one popularised by parents, but is it true? Most of the ingredients in chewing gum — sugar, flavourings, mint oils — are easily digestible.
The gum base is fairly resistant to your stomach’s acid and digestive enzymes, but according to US-based paediatric gastroenterologist David Milov, that doesn’t mean it sticks around in your stomach for seven years. It generally makes its way down the digestive tract, unless you’ve swallowed a massive amount — in which case, see a doctor.
CHICKEN SOUP CAN CURE A COLD
CHICKEN soup — which is often called ‘Jewish penicillin’ — is infomonly consumed by cold and flu sufferers, and has been praised by Jewish scholars for its health-restoring ability for centuries.
And there’s some truth to it. The broth of various vegetables and chicken bones is cooked for hours, which causes the release of health-boosting minerals zinc, calcium and magnesium into the liquid.
Medical experts have various theories as to how the soup actually relieves cold symptoms, including its heat helping to clear a blocked nose; its zinc content helping to shorten the duration of a cold; the hot water keeping you hydrated; and the soup’s anti-inflammatory properties helping to alleviate symptoms. So, while it’s not a cure as such, it can certainly help to make you feel better.