Old wives' food tales - the truth revealed

Every one of us can reel off a stack of the old wives’ tales. They are things we’ve heard over and over since childhood: eat your crusts and you’ll get curly hair; munching on carrots will help you see in the dark... on and on they go. They are received wisdom; some people believe these “facts” unquestioningly.

 

It’s a subject that Dr Ronald McCoy has thought a lot about. He’s a senior medical educator and spokesperson for the Royal Australian College of General Practitioners. He also happens to have a deep interest in folklore, which saw him granted a National Folk Fellowship in 2008. “We have to look at our health from a rational point of view,” he says. “I love fairy tales, but I wouldn’t base my health on them. Underlying health myths is fear. We worry about our mortality; we worry about being sick and about dying. Fear is quite easy to feed, but we want rationality to win out. If you take action about your health based on fairy tales, it’s not going to be of any use.”

 

Time, then, to put some of the most common food-related beliefs to the test. Which are true and which are false?

 

 

No, says gastroenterologist Professor Terry Bolin, president of the Gut Foundation. “When you have diarrhoea you lose electrolytes, particularly sodium and potassium, and they need to be replaced – especially the sodium. Replacing electrolytes quickly is especially important for children. Soft drinks have a huge amount of sugar without any electrolytes.” Bolin says that if you do insist on using lemonade you should mix in some salt – around a teaspoon for a small bottle of lemonade, or three teaspoons for a 750ml bottle.

 

Rather than soft drinks, though, Bolin also says you’re far better using a fluid replacement such as Gastrolyte (sold in pharmacies) and letting nature take its course: “Most diarrhoea is all over within 24 to 48 hours and we never know what the cause is, because by the time you’d send off a stool sample and get the results back, the diarrhoea would be gone anyway. But diarrhoea that lasts for more than two days really needs to be investigated.”

 

 

Not so, says Dr pam Brown fellow of the Australasian College of Dermatologists. “There is no good data that support that theory, although it used to be in a lot of dermatology textbooks. It’s a myth that has a long history; it was originally touted in the early 1930s. There were a couple of studies in the 1960s and ’70s, but these studies were poorly designed and not well done. 

 

“We do know that food is possibly one of a great number of factors, including genetics and the structure of the diet, that lead to acne.” There is, she says, some evidence that high glycaemic load may affect the body’s production of the hormone androgen, “and androgen is one of the things that, in a genetically susceptible person, drives the development of acne lesions. But chocolate itself hasn’t been implicated.”

 

 

 

“It’s obviously not literally true,” says Dr Ronald McCoy, “but as a metaphor there’s a lot of truth to it. It recognises that fruit is an important part of the diet and needs to be included on a regular basis. But you notice it’s ‘an’ apple, not 50 apples a day. It should be part of a balanced diet. And while apples are full of antioxidants, it doesn’t have to be an apple; it’s symbolic of fruit in general. So the gist of it is quite sound: moderate amounts of fruit as part of a balanced diet are an important factor in improving longevity.”

 

 

 

“There is no evidence that cranberry juice or cranberry tablets will treat an established infection,” says Dr David Malouf, president of the Urological Society of Australia and New Zealand. “A bladder infection should be managed with antibiotics prescribed by a doctor. An untreated infection can spread to the kidneys (called pyelonephritis), which can make the patient very unwell.

 

“However, there is evidence that regular cranberry juice or cranberry tablets may reduce the risk of developing a urinary tract infection (UTI) in the fi rst place. The current thinking is that cranberry stops the bacteria – the germs that cause UTIs – from adhering to the bladder wall. It’s one of several strategies a patient with recurrent UTIs might try to reduce the chance of re-infection.