Sun danger overrides vitamin need
LYING in the sun without sunscreen in order to increase vitamin D levels necessary for healthy bones is needless and increases the danger of skin cancer, according to new guidelines issued to combat public confusion over how to balance the risks.
The revised guidelines on how much sun is required to ensure adequate vitamin D — which is made in the skin on exposure to UVB rays in sunlight — give recommended sun exposure limits for each capital in summer and winter, and emphasise that sun protection is required when the UV index is 3 or higher.
In summer, most Australians will get all the sun they need by a few minutes of normal daily activities, such as walking to the shops in the morning and afternoon when the sun is less intense, and that deliberate sun exposure is therefore unnecessary.
In winter, however, residents of southern states — Victoria, Tasmania and South Australia — don’t need to use sun protection for up to two to three hour stretches, because the UVB rays are not strong enough.
In these cases, people can ensure adequate levels of vitamin D— which is made when the skin is exposed to sunlight — by spending two to three hours with their face, hands and arms exposed to the sun over the course of a week.
Sun protection is still necessary all year round in the Northern Territory, Queensland and parts of Western Australia, where UV levels remain high enough to damage skin through winter.
More specific advice applies to people who are either at higher risk of vitamin D deficiency — such as dark-skinned people, Muslim women or others who cover their skin, the elderly and babies of vitamin D deficient mothers — and those at higher risk of skin cancer, such as people who have had skin cancer before. These people should ask their doctor whether they need vitamin D supplements.
Vitamin D is starting to be credited with a larger role in good health than previously thought. Studies published recently have suggested it may cut the risk of breast, ovarian, colon and other cancers by up to 50 per cent, although too high a dose can also cause the body to absorb too much calcium and damage liver and kidneys.
The new guidelines, endorsed by the Cancer Council Australia, Osteoporosis Australia, the Australasian College of Dermatologists and the Australian and New Zealand Bone and Mineral Society, were launched in Melbourne yesterday.
Cancer Council CEO Ian Olver said the ‘‘ wrong people’’ were concerned about vitamin D deficiency and research showed 17 per cent of teenagers and 13 per cent of adults mistakenly thought they needed to spend time in the sun without sunscreen in order to boost vitamin D levels.
‘‘ We’re alarmed that a small but significant number of Australians are deliberately seeking sun exposure without sun protection because they’re concerned about vitamin D, and are therefore more likely to be putting themselves at risk of skin cancer,’’ Professor Olver said.
‘‘ The reality is that too many Australians get too much sun in summer and increase their risk of cancer, while some people don’t get enough sun, particularly in winter, and risk vitamin D deficiency with possible serious health consequences.’’
Professor Peter Ebeling, medical director of Osteoporosis Australia, said anyone who thought they were vitamin D deficient ‘‘ should seek medical advice, not seek more sun’’.
The new guidelines also say there is ‘‘ emerging evidence’’ that the optimum level of vitamin D to maintain healthy bones may be 50 per cent higher than the current recommended level — 75 nanomoles per litre, instead of the current 50 nmol/L. ‘‘ For the Australian population to achieve this [higher] level without putting themselves at greater risk of skin cancer through increased sun exposure, there would have to be an increased requirement for dietary sources of vitamin D,’’ the guidelines say.
‘‘ Given foods with naturally occurring vitamin D currently contribute very little to daily intake for Australians, the fortification of core foods should be considered.’’
Soaking it up: To maintain vitamin D levels, get some sun on about 15 per cent of the body – including face, arms and hands, for the recommended time