SummaryRead the full fact sheet
- Vitamin D is a hormone that controls calcium levels in the blood. It is needed for strong bones, muscles and overall health.
- The sun’s ultraviolet radiation (UV) is the main cause of skin cancer and the best natural source of vitamin D. There is a balance between the risk of skin cancer from too much sun exposure and maintaining adequate vitamin D levels.
- Vitamin D levels change naturally with the seasons. The amount of UV exposure you need depends on the time of year, UV levels, your skin type and existing vitamin D levels.
- Being physically active outdoors will help your body to produce vitamin D.
- The body can only absorb a limited amount of vitamin D at a time. Spending extra time in the sun won’t increase vitamin D levels – but will increase your risk of skin cancer.
- Some people are at increased risk of low vitamin D – this includes people with naturally very dark skin and people who have very low exposure to sunlight.
Sources of vitamin D
The body can only absorb a limited amount of vitamin D at a time. Spending extra time in the sun will not increase vitamin D levels but will increase your risk of skin cancer.
Other sources of vitamin D include:
Vitamin D in food
Small amounts of vitamin D can be obtained through food (about 5–10 per cent). However, it is difficult to obtain enough vitamin D from diet alone.
Food sources include:
- fatty (such as salmon)
- margarine and some have added vitamin D
- some cereals have added vitamin D.
UV levels vary depending on the time of year, time of day and location. Sun protection is recommended whenever UV levels reach 3 and above. In some parts of Australia, UV levels are 3 and above every day throughout the year. In southern regions, UV levels are usually below 3 during winter months.
During these times use a combination of sun protection measures, including:
- SPF30 (or higher) broad-spectrum, water-resistant sunscreen
- a wide-brimmed hat
- cool, covering clothing
- sunglasses (labelled AS1067)
UV levels in Victoria
From mid-August to the end of April, average UV levels in Victoria are 3 and above for much of the day so sun protection (clothing, sunscreen, hats, shade and sunglasses) is recommended. During these summer months, most people only need a few minutes outside on most days to absorb sufficient vitamin D.
Sensible sun protection measures should not put people at risk of vitamin D deficiency.
From May to mid-August, average UV levels in Victoria are typically low (below 3). During this time sun protection is not recommended unless you work outdoors, are near highly reflective surfaces (like snow), or are outside for extended periods. During these months, people should spend time outside in the middle of the day with some skin uncovered to maintain vitamin D levels.
Overexposure to UV is never recommended, even for people who have vitamin D deficiency.
Vitamin D deficiency
Vitamin D deficiency does not always have obvious symptoms but without treatment there can be significant health effects. Some people may experience bone and muscle pain, and softening of the bones.
It is important to achieve a good peak bone mass early in life. Vitamin D deficiency can result in a decline in bone density, increasing the risk of:
- falls and bone fractures (especially for older people)
- (in infants and children) – a preventable bone disease, and osteomalacia (in adults)
- Vitamin D deficiency can also be associated with low levels of calcium.
Who is at risk of vitamin D deficiency?
You may be at greater risk of vitamin D deficiency if you:
- have naturally very dark skin – this is because the pigment (melanin) in dark skin can partially block UV radiation from being absorbed
- avoid the sun due to previous skin cancers or sensitive skin
- spend a long time indoors and have limited sun exposure (such as nightshift workers, or those who are housebound or in residential care)
- wear a covering to conceal your body (such as for religious or cultural reasons)
- have a disability or condition that affects vitamin D metabolism – such as end stage liver disease, kidney (renal) disease or fat malabsorption syndromes (such as , and inflammatory bowel disease)
- take medication that affects vitamin D absorption
- are a breastfed baby of a mother who is vitamin D deficient (formula milk is fortified with vitamin D).
If you are at risk of vitamin D deficiency you should seek advice from your GP.
Treating vitamin D deficiency
Treatment options for vitamin D deficiency include improved sunlight exposure, diet, and exercise.
Your doctor may also give advice on ensuring you have sufficient calcium intake.
Once your vitamin D deficiency is treated, the aim is to maintain normal vitamin D levels.
Where to get help
- , 2017, Department of Health and Human Services, Victorian Government.
- , 2017, Nutrient Reference Values for Australia and New Zealand, Australian National Health and Medical Research Council and New Zealand Ministry of Health.
- , 2018, Australasian College of Dermatologists, Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia, Cancer Council Australia, Endocrine Society of Australia.
- , Australian Radiation Protection and Nuclear Safety Agency.
- , 2018, Royal Children’s Hospital.
- , 2019, Royal Children’s Hospital.
- , 2020, Royal Children’s Hospital.
- , 2021, Healthy Bones Australia.
- Osteoporosis prevention, diagnosis and management in postmenopausal women and men over 50 years of age – Diet and lifestyle, Royal Australian College of General Practitioners.
- Pregnancy Care Guidelines – Vitamin D status, 2019, Australian Government Department of Health.
- , Cancer Council.
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