Common health myths revealed

We've all heard the advice. Everyone knows it's true.....isn't it? We lift the lid on some common health myths to help separate fact from fiction. 

Does antiperspirant cause breast cancer?

The idea that antiperspirant and deodorant cause breast cancer is a myth, says Dr Jana Witt, health information officer at Cancer Research UK. And any concern is unnecessary, as there is absolutely no convincing evidence to substantiate what simply amounts to poor science and rumours.

“Scientists have looked at these claims closely, and have found them unconvincing,” says Dr Witt. “Most have no real biological foundation and a lot of the research is of low quality.”

Antiperspirants and deodorants are applied underarm to suppress sweating and odour, and it is their use so close to breast tissue that has sparked worry in the past. “However, breast cancer occurs in the breast, not in the underarm lymph nodes,” explains Dr Witt. “There isn’t any solid evidence about a link with cancer.”

Cancer Research UK reviews all the new evidence that emerges and publishes information on its website. Anyone with concerns is urged to contact the organisation for authoritative advice and support.

Does cracking your knuckles cause arthritis?

There is something visceral about the cracking of knuckles, that spine-tingling popping sound that accompanies the overextension of the fingers. It is a practice beloved by some, yet irritating to others.

Most knuckle crackers will have been told – probably in an effort to get them to stop doing it – that they risk arthritis if they continue. The scientific community, though, says there is no hard proof to back that up.

“We have no evidence that cracking your knuckles causes arthritis in the long term: there simply haven’t been good studies to make a decision about this,” says Professor Philip Conaghan of the academic unit of musculoskeletal medicine at the University of Leeds.

Professor Conaghan, a spokesperson for Arthritis Research UK, adds: “However, knuckle cracking may be associated with tendon and other soft-tissue problems.”

Knuckles are lubricated by synovial fluid, a yolk-like substance that reduces friction between the bones, easing movement. Cracking happens when the joints are stretched to the point that bubbles of dissolved gases are formed, which then pop. Once a knuckle is cracked, it takes about 15 minutes for the gases to reform.

Is drinking two litres of water a day beneficial?

Given that the adult human is made up of around 65% water, it comes as no surprise that we need to top up with the stuff regularly to stay well.

The European Food Safety Authority (EFSA), based in Parma, Italy, has investigated optimum intake and concludes that, for men, 2.5 litres a day is generally adequate under normal conditions, while women are advised to drink two litres. “Adequate intake refers to total water intake, including drinking water, water from beverages of all kinds and water from food moisture,” says an EFSA spokesperson. “Intakes should be increased under conditions that promote high water loss, such as when it’s very hot, during intense physical exercise, or if there is vomiting or diarrhoea.”

You are not drinking enough if you’re thirsty or your urine is dark and urination is infrequent and low volume. These signs may be different for older people, and it’s hard to drink too much water, says the EFSA: “Overconsumption that exceeds the kidneys’ capacity to eliminate that water is not easy to achieve.”

Does vitamin C prevent colds?

Ever since the 1930s, when vitamin C was discovered, scientists have been trying to establish whether it can prevent the common cold.

In an effort to finally answer the question, in 2012 a group of researchers pulled together all the studies held by the Cochrane Library and examined the findings.

“We hoped the authors would be able to clear things up,” says investigator Chris Del Mar, professor of public health at Bond University in Queensland, Australia. “Instead, we found conflicting conclusions and further confusion.”

In a nutshell, it seems that vitamin C does not prevent colds, but could shorten their effects. “A few of the trials indicate vitamin C taken in very big doses by marathon runners and army personnel undertaking training in extreme conditions might bring benefit,” says Professor Del Mar. “For the rest of us, taking such high doses of vitamin C would not be a good idea.”

Prof Del Mar believes more research is needed. “Until we know for sure, I’d suggest a better way of preventing infections is to wash your hands more often.”

Is a gluten-free diet the healthier option?

“Under certain circumstances, following a gluten-free diet is absolutely the right thing to do,” says dietician Dr Amanda Squire, a lecturer at Cardiff Metropolitan University and British Dietetic Association spokesperson. “However, if you are not gluten intolerant, it’s just a waste of money.”

Gluten-free diets have long been used to treat coeliac disease, a condition caused by intolerance to the protein in wheat that causes gastrointestinal disturbance. People who are diagnosed with a gluten allergy also sometimes benefit from cutting out wheat, and perhaps barley and rye. For the rest of us, it’s simply an expensive food fad.

“I recently bought coconut flour, the latest trendy alternative to wheat, and it cost a fortune,” says Dr Squire. “The idea was to make coconut bread, but in the end I had to smother it in jam to make it palatable. It was vile.”

Dr Squire has particular concerns about parents who think going gluten free will help children with autism and ADHD.

“These children risk malnourishment, and parents ought to speak to their GP about getting a referral to a dietician instead.”

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