By Dr Shevonne Koh
Maintaining bone health involves multiple factors. Understanding these is essential for optimising your bone strength and overall well-being.
Letter to the Editor
Vitamin D
Vitamin D deficiency is common in Tasmania, particularly during winter and spring due to reduced sunlight exposure and limited supplementation. Vitamin D is essential for bone growth and maintenance, calcium absorption in the gut and regulation of calcium levels in the blood. Adequate levels of both Vitamin D and calcium can reduce fracture risk, especially in older adults.
Vitamin D levels vary seasonally, peaking in late summer and reaching their lowest point at the end of winter. Deficiency can lead to poor bone mineralisation, causing rickets in children and osteoporosis (porous bones) or osteomalacia (demineralised bones) in adults. Low levels of Vitamin D have also been linked to depression, fatigue and cognitive difficulties. Vitamin D is stored in fat and muscle and released slowly over time. If you are at risk, your doctor may recommend a blood test to assess your levels.
People at higher risk of deficiency include:
- Older adults (especially those in residential care)
- People with limited sun exposure (e.g. those who are veiled, dark-skinned, or work indoors)
- Pregnant and breastfeeding women
- Adolescents with high growth demands
- Individuals with conditions affecting gut absorption (e.g. coeliac disease, inflammatory bowel disease)
- People with liver disease (due to reduced synthesis and enhanced degradation of Vitamin D)
Sources of Vitamin D
Sunlight is the primary source of Vitamin D in Australia. UVB rays trigger production in the skin, but exposure through glass does not count, as glass filters out UVB. Safe sun exposure varies depending on the season, skin type, and location. Follow the Cancer Council Australia guidelines for sun safety when UV levels exceed 3, including wearing a hat, sunscreen, and protective clothing.
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Very few foods contain significant vitamin D. Small amounts are found in egg yolks, liver, oily fish (e.g. salmon, tuna, mackerel) and fortified products (e.g. milk and cereals). Check out the table at this link that shows the recommended limited sun exposure for Vitamin D based on location in winter: https://healthybonesaustralia.org.au/your-bone-health/vitamin-d-bone-health/
Vitamin D Supplementation
If you are Vitamin D deficient, your doctor may recommend Vitamin D3 supplements – these are available as tablets, capsules, or drops. While deficiency is usually easy to correct, it may take several months. Excessive supplementation can cause toxicity, so always follow medical advice.
| Example Circumstance | Recommended Vitamin D Intake |
| People who obtain some sun exposure but not at the recommended level | Adults at least 600IU per day, over 70 years at least 800IU per day |
| Sun avoiders or people at risk of vitamin D deficiency | Higher doses may be required 1,000 IU – 2,000 IU per day |
| Moderate to severe vitamin D deficiency | 3,000 – 4,000 IU per day for 6-12 weeks to raise the level of vitamin D quickly, followed by a maintenance dose of1,000 -2,000 IU per day, as advised by a doctor. |
Source: Healthy Bones Australia https://healthybonesaustralia.org.au/your-bone-health/vitamin-d-bone-health/
Calcium
Calcium is vital for bone strength and structure. It also supports heart, muscle, nerve and blood function. When dietary calcium is insufficient, the body draws calcium from bones, reducing bone density and increasing the risk of osteoporosis. 50% of Australians do not meet their recommended daily calcium intake. A calcium rich diet remains the best way to support bone health. Foods naturally high in calcium include dairy products, leafy green vegetables, almonds and fortified foods. Below is a table on the recommended intake and guidance based on age:
| Lifestage | Age | Recommended Intake | Guidance |
| Children | 1-3 years | 500 mg per day | Growing bones require daily calcium intake. Daily dietary recommendations increase as children grow. |
| Children | 4-8 years | 700 mg per day | Growing bones require daily calcium intake. Daily dietary recommendations increase as children grow. |
| Girls & Boys | 9-11 years | 1,000 mg per day | Growing bones require daily calcium intake. Daily dietary recommendations increase as children grow. |
| Teenagers Girls & Boys | 12-18 years | 1,300 mg per day | Adequate calcium intake maintains bone strength. |
| Adults | 19 years + | 1,000 mg per day | Adequate calcium intake maintains bone strength. |
| Older Adults | Women 50 years + | 1,300 mg per day | The daily recommendation increases as calcium is less effectively absorbed from the intestine, and more can be lost through the kidneys.. |
| Older Adults | Men 70 years + | 1,300 mg per day | The daily recommendation increases as calcium is less effectively absorbed from the intestine, and more can be lost through the kidneys. |
Source: https://healthybonesaustralia.org.au/your-bone-health/calcium/
Weight-bearing exercise
Exercise is crucial for maintaining and improving bone mineral density (BMD) in Australians, helping to reduce the risk of osteoporosis and fractures. Weight-bearing and resistance activities stimulate bone formation and slow bone loss, which is especially important as people age. Regular physical activity, combined with adequate calcium and vitamin D intake, supports stronger, healthier bones across all age groups.
Bone mineral density (BMD) testing
BMD testing, commonly done via a DEXA (Dual-energy X-ray Absorptiometry) scan, helps diagnose osteoporosis and assess fracture risk. This low-dose X-ray measures bone strength and mineral content.
In Deloraine, The Bone Bus is a mobile bone densitometry service that provides local access to DEXA scans, reducing the need to travel. The Bone Bus is currently undergoing repairs but is expected to return later this year. The community will be notified once it resumes service. DEXA scans are available at other radiology centres but will require travel to Launceston and are subject to provider costs. BMD testing requires a referral and is subject to eligibility criteria. If you are concerned about your bone health, speak to your doctor to determine whether a scan is appropriate.
In the Meander Valley, sunlight might be scarce at times, but your bone density doesn’t have to be. A bit of safe sun, good nutrition, supplementation under the watchful eye of your doctor and weight-bearing exercise will keep your bones strong and steady. Don’t let your bone health slip, check in with your GP and stay on top of it.
References:
https://healthybonesaustralia.org.au/your-bone-health/vitamin-d-bone-health/
https://www.racgp.org.au/getattachment/631e40c5-1ce1-4da9-aeec-9c0b1ff1a515/attachment.aspx
https://www.nps.org.au/news/vitamin-d-supplementation
https://www.thebonebus.com.au/
