✓Standard Care

Understanding Vitamin D Deficiency in Australia

Q: How is vitamin D tested in Australia?

Vitamin D is measured through a blood test called 25-hydroxyvitamin D (25-OH-D). A small blood sample is taken and sent to a pathology laboratory. Results are typically available within a few days. If your GP orders the test with a clinical indication, it may be covered by Medicare.

Q: What is a normal vitamin D level in Australia?

In Australia, a vitamin D level of 50 nmol/L or above is considered adequate for bone health. Levels between 30-50 nmol/L indicate mild deficiency, while levels below 30 nmol/L indicate moderate to severe deficiency. Some practitioners consider levels above 75 nmol/L optimal, though evidence for benefits above 50 nmol/L is mixed.

Q: How long does it take to improve vitamin D levels?

With appropriate supplementation, most people see improvement in their vitamin D levels within 6-8 weeks. Your GP will typically recommend retesting at 3 months to confirm your levels have reached the target range. The time it takes depends on your starting level and the dose prescribed.

Q: Why are Australians deficient despite all our sunshine?

Modern Australian lifestyles mean most people work indoors during peak UV hours. Sun protection measures (which are important for preventing skin cancer) also reduce vitamin D synthesis. Southern states have insufficient UV during winter for vitamin D production, and Australia's diverse population includes many people with darker skin who need longer sun exposure.

Q: Can vitamin D deficiency cause fatigue?

Yes, fatigue is one of the most common symptoms of vitamin D deficiency. Vitamin D receptors are present in muscle tissue and are involved in energy production. Studies have shown that people with vitamin D deficiency often report significant fatigue, and supplementation can improve energy levels in those who are deficient.

Despite being the sunburnt country, 1 in 4 Australians are vitamin D deficient

Published 19 January 2026 · 8 min read

1 in 4

Australians are vitamin D deficient despite abundant sunshine

Source: [1]

The Short Answer

Vitamin D deficiency is surprisingly common in Australia. Despite our reputation as the sunburnt country, 23% of Australian adults are vitamin D deficient, with rates climbing to 40-50% in southern states by the end of winter. Recognising the symptoms early can help you address this correctable deficiency.

The Australian Vitamin D Paradox

Australia is known as the sunburnt country, yet vitamin D deficiency is remarkably common. The statistics may surprise you:

The Numbers

23% of Australian adults are vitamin D deficient (<50 nmol/L)
Up to 50% may have inadequate levels by the end of winter
40% of adults in southern states (Victoria, Tasmania, South Australia) are deficient during winter months

Common Symptoms of Low Vitamin D

Vitamin D deficiency often develops gradually, and symptoms can be subtle. Many people attribute them to stress, ageing, or simply being tired. Here are the five most common signs to watch for:

1. Fatigue and Tiredness

Persistent fatigue is one of the most common symptoms of vitamin D deficiency. Vitamin D receptors are present in muscle tissue, and inadequate levels can affect energy production at the cellular level.

Unlike normal tiredness that improves with rest, vitamin D-related fatigue tends to be persistent and can significantly impact your quality of life. Studies have shown that supplementation can improve fatigue scores in people with documented deficiency.

2. Bone and Muscle Pain

Vitamin D is essential for calcium absorption and bone health. Without adequate vitamin D, your body cannot properly absorb calcium from your diet, which can lead to:

Generalised bone aches, particularly in the lower back, hips, and legs
Muscle weakness and cramps
Increased risk of stress fractures
In severe cases, osteomalacia (softening of the bones)

3. Mood Changes

The brain has vitamin D receptors in areas associated with mood regulation. Research has linked vitamin D deficiency to:

Low mood and depressive symptoms
Seasonal affective disorder (SAD)
Anxiety
Irritability

Interestingly, mood symptoms often worsen in winter when both sunlight exposure and vitamin D levels are lowest. While vitamin D deficiency is not the sole cause of mood disorders, addressing it may help as part of a comprehensive approach.

4. Frequent Infections

Vitamin D plays a crucial role in immune function. It helps activate T cells, which are your body's first line of defence against pathogens. People with low vitamin D may experience:

More frequent colds and flu
Longer recovery times from illness
Recurring respiratory infections

Research has shown that vitamin D supplementation can reduce the risk of acute respiratory infections, particularly in those who are deficient.

5. Slow Wound Healing

Vitamin D is involved in controlling inflammation and fighting infection, both of which are essential for proper wound healing. If you notice that cuts, scrapes, or surgical wounds seem to take longer than expected to heal, vitamin D deficiency could be a contributing factor.

Important Note

These symptoms can have many causes. If you're experiencing any of them persistently, it's worth discussing with your GP, who can determine whether vitamin D testing is appropriate for you.

Why Australians Are at Risk

The paradox of vitamin D deficiency in a sun-drenched country comes down to modern Australian lifestyles:

Indoor lifestyles

Most Australians work indoors during peak UV hours (10am-2pm) when vitamin D synthesis is most efficient. By the time we leave work, UV levels are often too low.

Sun protection success

The Slip, Slop, Slap campaign has been incredibly successful at preventing skin cancer, but it has also reduced vitamin D synthesis. Sunscreen with SPF 30+ blocks about 95% of UVB rays.

Southern latitude

Melbourne, Hobart, and Adelaide are at latitudes where UV levels during winter are insufficient for vitamin D production, regardless of how much time you spend outdoors.

Changing demographics

Australia's increasingly diverse population includes many people with darker skin, who need longer sun exposure to produce the same amount of vitamin D.

When to Consider Testing

If you have risk factors for vitamin D deficiency, testing can help identify whether your symptoms might be related to low levels. Consider testing if you fall into any of these categories:

Risk Factor	Why It Matters
Office workers	Limited midday sun exposure during peak UV hours when vitamin D synthesis is most efficient
Older adults (65+)	Skin becomes less efficient at producing vitamin D with age, and many older adults spend more time indoors
People with dark skin	Higher melanin levels reduce vitamin D synthesis; may need 3-6 times more sun exposure
Those who cover skin	Religious, cultural, or personal preferences for covering skin limit UV exposure
Southern states residents	Melbourne, Hobart, and Adelaide have insufficient UV for vitamin D production during winter months
Malabsorption conditions	Conditions like coeliac disease, Crohn's disease, or gastric bypass surgery affect absorption

Understanding Your Results

Vitamin D is measured through a blood test called 25-hydroxyvitamin D (25-OH-D). Results are reported in nanomoles per litre (nmol/L). Here's what the numbers mean:

Below 30 nmol/LDeficient

Associated with increased risk of bone disease. Supplementation is typically recommended, often with higher initial doses.

30-50 nmol/LInsufficient

Mild deficiency. Supplementation or increased safe sun exposure is often recommended.

50-75 nmol/LAdequate

Sufficient for bone health and general wellbeing. This is the target range for most people.

Above 75 nmol/LOptimal

Some practitioners consider this optimal, though evidence for benefits above 50 nmol/L is mixed for most conditions.

Good News: Deficiency Is Correctable

Vitamin D deficiency is one of the most correctable nutritional deficiencies. With appropriate supplementation and sensible sun exposure, most people can improve their levels within 6-8 weeks, with retesting typically recommended at 3 months.

Your GP can advise on the right supplementation dose based on your test results and recommend safe sun exposure guidelines for your skin type and location.

Frequently Asked Questions

Vitamin D is measured through a blood test called 25-hydroxyvitamin D (25-OH-D). A small blood sample is taken and sent to a pathology laboratory. Results are typically available within a few days. If your GP orders the test with a clinical indication, it may be covered by Medicare.

In Australia, a vitamin D level of 50 nmol/L or above is considered adequate for bone health. Levels between 30-50 nmol/L indicate mild deficiency, while levels below 30 nmol/L indicate moderate to severe deficiency. Some practitioners consider levels above 75 nmol/L optimal, though evidence for benefits above 50 nmol/L is mixed.

With appropriate supplementation, most people see improvement in their vitamin D levels within 6-8 weeks. Your GP will typically recommend retesting at 3 months to confirm your levels have reached the target range. The time it takes depends on your starting level and the dose prescribed.

Modern Australian lifestyles mean most people work indoors during peak UV hours. Sun protection measures (which are important for preventing skin cancer) also reduce vitamin D synthesis. Southern states have insufficient UV during winter for vitamin D production, and Australia's diverse population includes many people with darker skin who need longer sun exposure.

Yes, fatigue is one of the most common symptoms of vitamin D deficiency. Vitamin D receptors are present in muscle tissue and are involved in energy production. Studies have shown that people with vitamin D deficiency often report significant fatigue, and supplementation can improve energy levels in those who are deficient.

Disclaimer:This information is educational only and not medical advice. Results should be interpreted by your health practitioner in the context of your symptoms and health history. Treatment decisions should be made with your doctor or specialist.