Up to a third of Australians are deficient in vitamin D, which is essential for strong bones, muscles and general health.
Vitamin D is crucial to bone and muscle development and in preventing osteoporosis. The most common source is exposure to sunlight. Ultraviolet radiation is responsible for vitamin D production in the skin.
Most people can maintain adequate vitamin D levels through a few hours of non-peak UV exposure a week. However, if your skin is very dark skin, you may need as much as three to six times the exposure.
People at risk of vitamin D deficiency include:
- Lack of sun exposure. The elderly, people who spend a lot of time indoors or those who wear covering clothing for religious or other reasons
- Breastfed babies. Babies are dependent on their mothers for their vitamin D levels
- Very dark skin. Skin pigment acts as a filter to UV
- Certain medical conditions. Some conditions affect vitamin D metabolism, including obesity, liver and kidney disease.
How much sun do you need?
10 minutes twice a day of non-peak UV sun exposure
two or three hours exposure a week of the face, hands, arms or legs
People with dark skin need more exposure and may need to take a vitamin D supplement to avoid deficiency.