Sarah Berry -Apr 5, 2012
Slip, slop, slap ... are we out of date? Photo: iStockphoto
Australia has one of the highest rates of skin cancer in the world. In fact, two in three Australians will be diagnosed with skin cancer by the time they are 70. In response to these alarming figures, The Cancer Council put the spotlight on skin cancer with the slip, slop, slap and sun smart campaigns run over the past few decades.
But, the flip side of slip, slop, slap (and wrap) is that Vitamin D deficiency is increasingly common in Australia and contributes to serious illness.
With one in three Aussies now insufficient in Vitamin D scientists are calling for a review of the sun smart message, saying there is a dangerous dark side to staying out of the sun.
"The negative publicity regarding sun exposure during the past 30 years has resulted in a vitamin D deficiency pandemic," says Dr Michael Hollick author of The Vitamin D Solution.
Biochemist and author Lyle MacWilliam, who was recently in Australia to talk at the USANA Health Sciences convention, agrees. He expressed serious concern at the current vitamin D recommendations in Australia and says that they are "seriously out of date."
"I respectfully submit that the governments of Australia and New Zealand have been remiss in keeping abreast of the emergent science on vitamin D and disease prevention," he says.
"In light of emergent research ... both Canada and the United States have recently moved to increase the recommended daily intake (RDI) for vitamin D to 600 IU per day - a level most experts contend is still too low. In contrast ... the RDI for Australia and New Zealand has not budged an inch. It remains at a miniscule 200 IU per day - a level far too low to provide any serious amount of protection."
It is widely known that Vitamin D helps to prevent brittle bones. But, it also improves immunity, susceptibility to infection and helps to ward off depression. In addition to this, recent studies suggest vitamin D can help to prevent cancer.
A four-year, double-blind, randomised placebo-controlled trial found that post-menopausal women who supplemented with 1,100 IU/day of vitamin D and 1,500 mg/day of calcium reduced their risk of dying from all cancers by more than 66 per cent.
"Vitamin D could be the single most effective means of preventing cancer - even outpacing the benefits of a healthy lifestyle," MacWilliam says.
Similarly, Dr Hollick says: "If you had to choose a single nutrient that would help you ward off heart disease, cancer, diabetes, obesity, dementia, influenza, bacterial infections, depression, insomnia, muscle weakness, fibromyalgia, osteomalacia, osteoarthritis, rheumatoid arthritis, osteoporosis, psoriasis, multiple sclerosis, and hypertension, it would be vitamin D."
To obtain sufficient blood levels of vitamin D, MacWilliam says it needs to come from sunlight. "You cannot obtain sufficient vitamin D through the diet - that is unless you are prepared to consume 3 or 4 tins of sardines or eat 50 to 100 eggs each day," he says.
While he recommends vitamin D supplementation (particularly during winter months when the sun isn't as strong) he says it is best absorbed through sunshine and people need around 10-20 minutes of regular unprotected full-body exposure when the sun is high in the sky (late morning or early afternoon). Only after this time should we be slapping and wrapping.
Contrarily, the Cancer Council currently says most people can get sufficient vitamin D from "a few minutes of exposure to sunlight on [your] face, arms and hands or the equivalent area of skin on either side of the peak UV periods (10am to 3pm)"
The stark difference between the two recommendations is not lost on Ian Olver, chief executive of Cancer Council Australia.
"My basic comment is this: when there are large differences between American and Australian government [regulations] it suggests we're not dealing with a black and white situation," he says. "If it was then we'd be doing the same thing."
Olver says that the grey area reflects different countries’ interpretations of current data.
"We need to do more research to [determine] the accuracy of measurement of vitamin D, what the levels should be and precisely how much and the intensity of sunlight you need."
Having said this, he does agree that it is a tricky topic to tackle.
"Our concern is if you tell people [to go out in the sun] - and we don't want people vitamin D deficient, you do need sunlight - it's still a grey area of how much.
"Is it ten or fifteen minutes? The data isn't definitive. What is definitive is the number of people who get skin cancer and die."
Currently, over 1800 people in Australia die of skin cancer each year and skin cancers account for 80 per cent of all newly diagnosed cancers.
It is for this reason Olver says he is wary of "diluting the sun smart message especially in summer".
He notes that a lot of people still get sunburnt regularly and says that the amount you need is variable depending on the colour of your skin and where in Australia you live.
"The angle of the sun and [intensity] is different even between Queensland and Tasmania," he says.
For the time being the science and scientists remain divided.
"We're keen to keep looking at the literature and refining the message," he says. "Until the literature is strong enough that we find where the balance point is, I don't think making extreme statements on either side is helpful."