Sun Exposure and Vitamin D Supplementation Study

Most people in Australia get over 90% of their vitamin D requirements through exposure of the skin to sunlight. Having enough vitamin D is very important for healthy muscles and bones and probably also for your immune system. But too much sun to the skin causes skin cancers.

 Australia has the highest skin cancer incidence in the world, however Vitamin D deficiency is also becoming increasingly common. So, balancing the risks and benefits of sun exposure is a challenge and a worry for many Australians. We have great sun protection programs, to ensure safe sun exposure and avoid skin cancer; but we don’t know how much sun exposure you need, in different parts of Australia, to keep vitamin D levels high enough, throughout the year.

Blood testing for vitamin D deficiency is now very common in Australia, but it is not clear if people with mildly low levels should just be given advice to safely increase sun exposure or be advised to take a vitamin D supplement.

The SEDS Study aims to provide evidence to support public health messages about optimal sun exposure by:

  1. Assessing how effective sun exposure advice is in managing mild vitamin D deficiency.
  2. Comparing the effect of sun exposure advice and vitamin D supplements on vitamin D levels in the blood.
  3. Measuring the effects of sun exposure and vitamin D supplements on bone health and immune function.

The SEDS Study is a multi-centre clinical trial in four regions of Australia: Canberra, Brisbane, Melbourne and Perth, involving around 400 participants. For more details about this study please see

The SEDS Study is funded by a research grant from Cancer Australia.


    The SEDS Study is being conducted by doctors and scientists at the National Centre for Epidemiology and Population Health (Canberra), Queensland Institute of Medical Research (Brisbane), Australian Radiation Protection and Nuclear Safety Agency (Melbourne), Telethon Kids Institute (Perth), Cancer Council Western Australia (Perth) and Curtin University (Perth).