Vitamin D levels and bone health
Do you spend less than 10 minutes outside each day with some skin exposed to sunlight and without taking vitamin D supplements? If so, you may be at risk of having low vitamin D levels. Vitamin D is naturally produced in the skin when exposed to UVB rays from sunlight. It plays a vital role in maintaining healthy bones by enabling the body to absorb calcium effectively, which is essential for building and preserving strong bone tissue. Without sufficient vitamin D, calcium absorption decreases, potentially leading to weaker bones and an increased risk of fractures.
Vitamin D levels and seasonal variation
Vitamin D levels naturally fluctuate throughout the year, typically peaking in late summer and reaching their lowest point at the end of winter. Healthy Bones Australia recommends maintaining a vitamin D level of at least 50 nmol/L year-round to support optimal bone health.
Your doctor may order a blood test to check your vitamin D levels, especially if you are at risk of deficiency. People who may be at risk include:
- Adults who spend most of their time indoors due to health reasons or work.
- Individuals with naturally dark skin, as higher melanin levels reduce UV light penetration.
- Those who avoid sun exposure due to skin protection or medical advice.
- People who cover their body for cultural or religious reasons.
- Individuals with medical conditions affecting vitamin D absorption or metabolism.
- Elderly individuals who are housebound or live in residential care.
- Pregnant or breastfeeding women.
Vitamin D deficiency
In Australia, over 30% of adults experience mild to severe vitamin D deficiency. This deficiency can:
- Increase the risk of osteoporosis.
- Cause bone and joint pain.
- Raise the risk of falls and fractures, especially in older adults.
- Vitamin D deficiency in pregnant women can affect the developing baby, potentially leading to rickets in severe cases, and has been linked to other health issues.
Vitamin D supplements
For those with low vitamin D levels, supplements may be necessary, as advised by a healthcare professional. While vitamin D deficiency can be corrected, it may take several months for levels to improve. Supplements come in various forms including tablets, capsules, drops, and liquids. Most supplements contain vitamin D3, and doses are measured in International Units (IU).
General dosage guidelines from Healthy Bones Australia:
Your doctor will tailor the dosage based on your individual needs, and pharmacists can provide additional advice about supplements.
Vitamin D and diet
Diet alone usually does not provide enough vitamin D to meet your needs. Some foods contain small amounts of vitamin D, including egg yolks, liver, oily fish (such as salmon, tuna, mackerel, and herring), and selected fortified products like milk powder, margarine, and cereals. Download the Fact Sheet: Vitamin D + Bone Health printable information.