What is Vitamin D?
Vitamin D is a nutrient that has many important functions to help maintain good health
What does Vitamin D do?
Vitamin D has been shown to:
- benefit bone health. Vitamin D is required for the body to absorb calcium from our food. Adequate level of calcium is important against developing osteoporosis.
- protect against some cancers, especially colon cancer, prostate cancer and breast cancer
- help with the function of muscles and nerves
- help with immune function
How is Vitamin D produced?
Vitamin D is produced through a process that starts when the skin is exposed to the UVB rays of the sun. This is the main source of Vitamin D.
A small amount of Vitamin D is also obtained from certain foods. This is normally not enough for your body's requirements.
Foods that contain Vitamin D include oily fish (such as salmon, tuna and mackerel), cod liver oil, cheese and egg yolks. Certain types of milk and margarine may have vitamin D added into them.
How much sun do I need to get enough Vitamin D?
The amount of sun you need for adequate vitamin D depends on:
- UV index – which changes with the time of the day
- How much of your skin is exposed to the sun
- Your skin type
What is the UV index?
The UV index is a number issued by the Bureau of meteorology which is used to describe the strength of the sun's UV rays for a certain place on a certain day. It acts as a guide to help people avoid overexposure to the sun's UV rays when it is at harmful levels.
A UV index of 3 and above may damage your skin within a short exposure time and lead to increased risk of skin cancer.
A UV alert (in the form of a color coded graph) is issued by the Bureau of Meteorology, which will show the times of the day when the UV index is above 3. At these times, it is important to protect your skin from the sun.
Remember that UV radiation cannot be seen or felt, so the heat of the sun is not an accurate measure of the strength of the UV rays.
How much of my body do I need to expose to the sun to get enough Vitamin D?
In Perth, Western Australia, we are fortunate to have bright sunny days in summer that we can all enjoy.
During these summer months, most people will meet their vitamin D requirements by exposing their face, arms and hands for only a few minutes during the peak UV times (between 10am to 3pm) on most days of the week.
Remember that after a certain level, further sun exposure will not increase vitamin D production, but it will increase your risk of skin cancer.
Winter months may require two to three hours of total sun exposure per week to the face, arms and hands to get your vitamin D requirements.
Does my skin type affect the amount of sun I need to get enough Vitamin D?
Yes. Dark skinned( eg. Asians and Africans) people have more melanin production that gives them some natural protection against UV rays, but also means that less vitamin D is produced. These people may require as much as three to six times the amount of sunlight to get adequate amounts of vitamin D, compared to fairer skinned individuals.
Does using sunscreen mean I will not get enough Vitamin D production?
Not necessarily. Studies have shown that in real life conditions, regular sunscreen use does not significantly impact on vitamin D levels.
This was thought to be the result of more time spent in the sun (in the individuals who used regular sunscreen), so they already had adequate levels of vitamin D production.
How do I check if I have enough Vitamin D?
Vitamin D can be checked by a simple blood test. If this is found to be low, you can discuss your options with your GP or our skin cancer clinic doctors to assess the best way to increase your vitamin D levels.