By Mary Ward
In summer, Australia has one of the highest UV indexes in the world. So, it may be surprising to learn that about one in four of us are deficient in vitamin D.
At least 80 per cent of a person’s vitamin D intake comes through sun exposure, as the skin absorbs and converts UVB radiation.
Sydneysider Sarah Biggins-Gilchrist seeks to balance her daily vitamin D with sun protection.Credit: Dean Sewell
“We have surprisingly high levels of vitamin D deficiency considering our climate,” said Professor Rebecca Mason, a bone and skin researcher at the University of Sydney. She attributes the trend to both efforts to protect the skin from melanoma and lifestyle factors.
“Not everybody has an opportunity to be outside in the sun,” she said. “If you’re not well or mobile, you tend not to get outside. Office workers are inside for most of the day. And there are quite a few people in the community who wear covering clothing for modesty and custom.”
Doctors and health organisations will now be encouraged to give tailored advice about sun exposure to people with different skin types and living in different parts of Australia, in an effort to balance concern about skin cancer risk with the body’s vitamin D needs.
The new position statement on managing the risks and benefits of sun exposure, published last month, is backed by 13 organisations, including Healthy Bones Australia, Cancer Council Australia, and the colleges of GPs and dermatologists.
“It’s been a long time coming,” said Mason, who was involved in the statement’s development.
“The ‘slip, slop, slap’ message is great, but the reality is that people have different needs.”
Vitamin D deficiency is most common in the southern states and is highest in the winter months. In the most recent data on the topic, collected by the ABS in 2012, almost half of Victorians and about two in five people in NSW were recorded as deficient.
It was also particularly high among people who had darker skin or may cover their skin for religious or cultural reasons, with 67 per cent of Australians born in southern and Central Asia and half of those born in North Africa and the Middle East found to have inadequate vitamin D.
Under the new guidelines, people with pale skin that burns easily will continue to be recommended to use sun protection when the UV index is 3 or above and may require vitamin D supplements to ensure they are not deficient.
However, depending on their melanoma risk, periods of sun exposure may be appropriate for people with darker skin to improve their vitamin D levels.
“Melanin is very good at protecting the skin cells from sun damage, but it also means that you don’t make vitamin D so readily,” Mason explained, stressing that people with a family or personal risk of skin cancer, moles, or who were immunocompromised should limit sun exposure regardless of their skin type.
Consequences of severe vitamin D deficiency include rickets in children and bone issues in the elderly.
Mason said the latter was particularly significant for older people living in aged care, where vitamin D supplements are typically standard.
The three skin types, and how they should manage sun exposure
- Pale skin which burns easily: Sun protection is recommended when the UV index is 3 or above. Discuss vitamin D needs with a doctor (supplements may be needed).
- Olive, light brown and “darker white” skin that tans: Adequate vitamin D can be obtained by short and regular exposure to sunlight. After this, sun protection is recommended when the UV index is 3 or above. People with a personal or family history of melanoma who are immunocompromised or have other risk factors such as moles should always use sun protection when the UV index is 3 or above.
- Darker skin (deep brown to black): Longer sun exposure with bare skin, even in summer, is needed to maintain adequate vitamin D. Sunglasses are still essential.
Australian position statement on balancing risks and benefits of sun exposure, February 2024
Fatty fish is the best dietary source of vitamin D. However, Mason said studies had shown that boosting vitamin D levels with diet alone was difficult, so supplements were usually required.
A diet high in calcium will also assist.
“People who have a low calcium intake also seem to degrade their vitamin D more rapidly, and vitamin D helps the body absorb more calcium, so they work together for healthy bones,” Mason explained.
While vitamin D deficiency is recognised as an ongoing issue for Australians, dedicated testing is expensive. People typically learn they are deficient through a routine blood test, and as a result, it is difficult to know whether rates have increased since data was last collected in 2012.
“The truth is we don’t routinely monitor and measure population nutrition often enough in Australia,” said Tara Diversi, president of Dietitians Australia.
“We have been calling for a robust, comprehensive population nutrition monitoring program to be run at least annually. This would enable us, at a population level, to be better informed about nutrition deficiencies, including vitamin D.”
Sydneysider Sarah Biggins-Gilchrist tries to get out for a run when working from home to make sure she sees some sunlight.
“I haven’t ever tested my vitamin D levels, but it’s something I think about. I try to get a bit of sun every day,” she said, adding that she would also wear sunscreen when out.