In Australia and New Zealand, the prevalence of vitamin D deficiency varies, but it’s recognised to be much higher than previously thought, even though we live in a relatively sunny climate. Some experts acknowledge that between 25-60% of Australian adults and children may be vitamin D deficient.
Where can you find vitamin D?
Vitamin D is interchangeably known as a vitamin or hormone, naturally produced by the body when your skin is exposed to UVB sunlight. The best time for UVB sunlight exposure is between 10am–3pm and should be for a duration of between 5-10 minutes. You can also find small amounts of vitamin D in certain foods, such as cold-water fish, cod liver oil, dark green leafy vegetables, egg yolks and milk, but this is usually not enough to maintain good levels of vitamin D.
Vitamin D2 vs D3
There are two types of vitamin D: vitamin D2 and vitamin D3. Vitamin D2 (ergocalciferol) is a synthetic form of vitamin D, whereas vitamin D3 (cholecalciferol) is identical to the vitamin D produced naturally by UVB sunlight exposure. Vitamin D3 is much more effective at raising vitamin D levels in the blood, making it the preferable choice of vitamin D in nutritional supplements.
How much vitamin D is enough?
A daily dose of 1000IU of vitamin D3 has been found to increase vitamin D levels by 25nmols/L over a three- month period. Normal reference ranges for blood levels of vitamin D can vary between pathology laboratories, but it’s generally accepted that blood levels:
- Less than 50nmols/L indicate deficiency
- Between 52-72nmols/L indicate insufficiency
- Between 75-150nmols/L indicate sufficiency
Risk factors for vitamin D deficiency
A significant number of Australians do not receive enough vitamin D and the Australian government has taken steps to correct this by mandating vitamin D fortification in many dairy products. Common risk factors for a vitamin D deficiency include:
- Limited or inadequate exposure to sunlight – excessive sunscreen usage, confinement indoors
- Lifestyle factors – exposure to air pollution, being overweight, excessive alcohol intake
- Dietary deficiency – due to food restrictions such as a low-fat diet, intolerances or allergies
- Ageing – the skins capacity to produce vitamin D is decreased in the elderly
- Dark pigmented skin – the pigment melanin in dark skin can’t absorb as much sunlight
- Medications – including some powerful anti-inflammatories, deplete vitamin D levels
- Malabsorption conditions – including coeliac disease and Crohn’s disease
- Women wearing a veil (particularly during pregnancy) and their infants
Vitamin D may assist in the prevention of vitamin D3 deficiency when dietary intake is inadequate and assists in the maintenance of general well-being. See Herbs of Gold Vitamin D3 1000.
The importance of vitamin D for health
Vitamin D plays a crucial role in many areas of your health and is important for:
- Healthy immune system function
- Healthy mood
- Normal sugar metabolism in healthy individuals
- Bone health - aids the absorption of calcium and is required for healthy bones and teeth, and helps maintain bone density and bone strength
- Muscle strength – helps maintain muscle strength and, by helping to maintain muscle strength, may reduce the risk of falls in the elderly
Pregnancy and breastfeeding - sufficient levels are required during pregnancy and breastfeeding for muscle and nerve development in infants