Common health myths busted
Artificial sweeteners cause cancer. A glass of warm milk will help you sleep. Cheese makes you constipated. We think they're all true except they aren't.
"There are many often-heard pieces of health lore that we believe because we never questioned them," says Dr Rachel Vreeman, co-author with Dr Aaron Carroll of Don't Cross Your Eyes… They'll Get Stuck That Way! (St Martin's Griffin, $19.95), a book that debunks health myths.
Like the fable that we only use 10 per cent of our brains "the truth is, most of your brain is pretty useful to you," she laughs most health myths are misguided but harmless. Others are not. Here are a few of the most misleading myths.
Artificial sweeteners can cause cancer.
"It's one of those myths that has left the realm of science and entered the realm of faith," says Vreeman. How did we take the leap?
According to Vreeman, of 50 noted studies on saccharine the world's oldest artificial sweetener 20 involved rats consuming the compound in massive doses for more than 18 months. ,p>Of those, only one study found a relationship between saccharine and bladder cancer but, she explains, "it was in a type of rat that is easily infected with a bladder parasite that can leave it more susceptible to cancer". Research on the rats' offspring found the males developed more cases of cancer.
From that one study, countries worldwide banned saccharine while the US put out health warnings. Even so, there's not been a study linking it to human cancer.
And while aspartame and other sweeteners have been tied anecdotally to increased cases of brain cancer in the elderly, there is "no clear link", says Vreeman.
Green mucus means you have an infection.
Although widely believed by medical professionals, the green mucus and infection link is
just not true, says Vreeman. "The colour of snot is not the key as to whether or not you need an antibiotic." Rather, the sickly hue is due to neutrophils or white blood cells that "eat up germs, digest them and turn things green. It has a lot of iron in it and means your body is working."
Airing a wound helps it to heal.
Drying out a wound to promote scabbing may seem like common sense, but "this is completely backward", says Vreeman. "They heal when covered and moist. It's slower to heal if it's exposed to the air because it forms a larger scar since they are harder, dryer scabs."
So how did the notion arise? In the days before antiseptics and soaps, dressings weren't changed as often as they should have been, so wounds became moist and dirty, causing infection. "Keep the wound clean and covered," she says.
Cheese causes constipation.
"If you want to consider foods that get an unfair shake, it's worth talking about cheese," says Vreeman. Born from bowel movement studies of babies "parents are obsessed with babies' pooping", says Vreeman constipation has been linked to dairy protein in baby formula. "But baby constipation and childhood or adult constipation are two different issues."
Those who are lactose intolerant mostly experience bloating, diarrhoea and discomfort rather than constipation. "In fact, a study of people who reported sensitivity to dairy products found no statistically significant association with constipation."
For the full story, see the February issue of Good Health. Subscribe to 12 issues of GoodHealth for only $59.95 and receive an Invisible Zinc Pack, valued at $34.90.