Vitamin D and Sun Exposure – How Much is Enough?

Each year hundreds of patients ask our doctors how much sun exposure they should be getting to optimise Vitamin D levels in the body. It can be difficult to find a balance between getting enough sun exposure to create vitamin D, versus reducing the risk of skin damage by not overdoing sun exposure. In this article we explain what vitamin D is, who is at risk of deficiency and what the current sun exposure recommendations are, so you can decide on your best course of action.

What is Vitamin D?

Vitamin D forms in the skin when it is exposed to ultraviolet B or ‘UVB’ radiation from sunlight.  Exposing skin to sun is the best natural source of this essential vitamin. It is present in some foods including eggs, oily fish and dairy products with added vitamin D, however this makes up a tiny percentage of the body’s total levels and it is almost impossible to get enough vitamin D from diet alone.

Why do we need Vitamin D?

A vital ingredient for overall health and wellness, vitamin D assists the immune system and the body’s ability to fight infection. Also a factor in muscle and bone health, vitamin D helps the body absorb calcium. Low vitamin D levels can lead to bone fractures and pain, rickets and negatively impact a growing foetus if the mother has vitamin D deficiency.

Who is at risk of Vitamin D deficiency?

People most at risk of deficiency include:

  • Sufferers of chronic health conditions such as obesity, renal disease, cystic fibrosis, coeliac disease and bowel disease
  • People who are housebound or hospitalised for long periods of time
  • Night shift and indoor workers such as office and factory staff
  • People with darker skin as this reduces the penetration of UV light
  • Patients on certain medications – the body’s metabolism of vitamin D can be affected

The level of vitamin D in the body is generally at its lowest during winter and at the end of winter.

What are the different factors affecting Vitamin D production?

It is essential to strike a good balance between sun exposure and sun protection.  While sunlight exposure is the best source of vitamin D, there is still the risk of skin damage, skin cancer and melanoma from over-exposure.

The amount of sunlight needed to make vitamin D is highly individual and It is difficult to make an exact recommendation of how much sun exposure a person needs. Some of the factors that impact a person’s ability to create vitamin D include:

  • Skin type/colour – people with darker skin need more sun to create vitamin D
  • Age – older people can’t produce as much vitamin D
  • Amount of skin exposed to the sun – exposing larger areas of the body creates more vitamin D in less time
  • Lifestyle – people who spend a lot of time indoors will find it harder to produce vitamin D
  • UV level – higher UV means less time is needed
  • Location – proximity to the equator e.g. northern parts of Australia have higher UV levels all year round
  • Altitude – UV absorption is higher with altitude
  • Weather – cloud cover means less UV
  • Season – Less vitamin D is produced in winter
  • Time of day – more vitamin D is produced in a shorter time when the sun is high in the sky.

What are the recommendations for safe sun exposure?

According to Sunsafe Australia and the Cancer Council:

If the UV index is below 3, sun protection is not needed. It is recommended at these times people are outdoors in the middle of the day with some skin uncovered on most days of the week.

If the UV index is 3 or above, sun protection is required for any outdoor activity that lasts more than a few minutes. In summer, sun protection is vital.

UV levels peak at midday however in summer they can be above 3 from as early as 8.00am and as late as 4.30pm in some areas of Australia.

How can you check the UV index?

There are some great sites and apps to help you check the UV index and learn about safe sun exposure. Two of our favourites are:

The My UV website

The free SunSmart apps which are available for iphone & android.

If you have any concerns or questions about Vitamin D, think you may be deficient or want to have your skin checked, please make an appointment to see your GP. We are more than happy to help.