What is vitamin D deficiency?

Vitamin D deficiency occurs when your body doesn't have enough vitamin D. It's the most common nutritional deficiency worldwide.

Vitamin D is a fat-soluble vitamin that is very important for bone health.

You get vitamin D by exposing your skin to sunlight and from the foods you eat.

Most people are not able to get enough vitamin D from food alone. But in Australia, most people can get enough vitamin D with careful sun exposure.

What are the symptoms and complications of vitamin D deficiency?

While there are usually no symptoms of vitamin D deficiency, it is possible to have:

• mild bone pain
• muscle weakness
• tiredness

In adults, long-term vitamin D deficiency can cause loss of bone density and increase your risk of osteoporosis. Older people who don't have enough vitamin D are more likely to fall and fracture their bones.

In babies and children, ongoing vitamin D deficiency can cause rickets (where growing bones don't develop properly).

Vitamin D deficiency can also increase your risk of some chronic (ongoing) conditions such as:

• autoimmune conditions
• type 2 diabetes
• high blood pressure
• infections
• some cancers

Vitamin D deficiency has also been linked to some pregnancy complications, such as:

• pre-eclampsia
• preterm birth

Am I at risk of vitamin D deficiency?

You can get vitamin D deficiency if you don't get enough:

• skin exposure to sunlight
• vitamin D from the food you eat

There are also some conditions and medicines that can increase your risk of vitamin D deficiency. The risk of vitamin D deficiency is increased in people:

• living in care (such a hospitals, rehabilitation or aged-care facilities), especially older people
• who stay indoors most of the time
• who cover most of their skin with clothing (for example, for work or cultural reasons)
• with naturally dark skin
• who are pregnant or breastfeeding
• with advanced kidney disease

There are also seasonal changes that may affect your risk of vitamin D deficiency. For example, you may spend more time outdoors in warmer weather when there are more hours of UV light, and more time indoors in winter.

When should I see my doctor?

See your doctor if you are worried about vitamin D deficiency.

Also see your doctor if you think you may be at risk of vitamin D deficiency and are planning a pregnancy or are pregnant or breastfeeding.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is vitamin D deficiency diagnosed?

Your doctor will ask if you have any symptoms or risk factors for vitamin D deficiency. They will examine you and ask about your diet and health in general.

You doctor may recommend a blood test to check you vitamin D level.

If your doctor thinks you may have bone complications from an ongoing lack of vitamin D, they may recommend:

• extra blood tests
• x-rays or scans

How is vitamin D deficiency treated?

If you are low in vitamin D, your doctor may recommend that you:

• increase your intake of foods high in vitamin D
• try to get enough time in the sun (see below)
• take a vitamin D supplement

Check with your doctor about the correct dose before taking any vitamin D supplements.

Also, some people should not take vitamin D supplements, so always check first with your doctor or pharmacist.

Can vitamin D deficiency be prevented?

Enough exposure to sunlight is the best way to prevent vitamin D deficiency in Australia.

How much time you should spend in the sun depends on:

• your skin type — people with naturally darker skin need more sun exposure
• the amount of skin you expose
• where you are in Australia
• the time of year — season
• the time of day

It's important to balance the need for some sun exposure to make vitamin D with the risk of skin damage from the sun. If UV radiation is high (if the UV index is 3 or above), you should wear sun protection to reduce your risk of skin cancer.

In general, during the summer months anywhere in Australia, you only need to spend a very small amount of time outdoors on most days to get enough vitamin D. For many people this will be achieved through incidental sun exposure.

In most southern states in Australia during winter, it's possible to keep up your vitamin D levels by spending time outdoors with sufficient skin exposed during the middle of the day.

See the sunshine map to see how much sun exposure you need where you are in Australia.

Resources and support

See the Australian Guide to Healthy Eating.

The Cancer Council's SunSmart app can help you check your daily local sun protection times.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.