Do you need a Vitamin D check?
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Vitamin D is one of the latest trendy health issues. Five years ago, nobody thought to request a Vitamin D check from their doctor, but now everybody is getting their levels checked and Medicare is creaking under the cost of providing so many tests.
However, Australian guidelines advise against checking levels in low-risk, young people, because the long-term health consequences of mild Vitamin D deficiency are not clear.
So what is the role of Vitamin D in the body and how do you know if you are at high- or low-risk and should get your levels checked?
Vitamin D is essential for bone and muscle health. A very small amount of vitamin D is obtained from our diet, from oily fish and some dairy products, but the vast majority comes from sun exposure on bare skin. When UVB rays interact with cholesterol in the skin, Vitamin D is formed. Vitamin D improves calcium absorption from the gut and plays a key role in maintaining strong bones. It also seems to be essential for muscle and general health, and there is some evidence to show that it plays a role in reducing the risk of heart disease, cancer and diabetes; although the benefits of increasing vitamin D intake for the sake of these health problems are unknown.
So what causes low Vitamin D and how do you work out if you're at risk of Vitamin D deficiency?
Vitamin D deficiency can occur in three ways -
inadequate sun exposure
inadequate dietary absorption
increased use by the body of vitamin D
Those at risk of inadequate sun exposure are those exposed to less sun - the elderly, housebound and infirm, and those who for cultural reasons cover up all bare skin, and also those who less readily make Vitamin D - people with dark skin require 2-3 x more sun exposure to make Vitamin D than those of fairer skin, and the thinner skin of the elderly is less able to produce Vitamin D. For advice on the balance between adequate sun exposure and avoiding skin cancer check here.
Secondly, lack of dietary absorption from the gut can occur through strict vegan diets; in some medical conditions e.g. Crohn's disease or coeliac disease; and also when certain medications are prescribed.
And thirdly, Vitamin D is essential for growth, so pregnant and breast-feeding women and babies of mothers who are vitamin D deficient, are at increased risk of Vitamin D deficiency.
Vitamin D deficiency can be without symptoms, or can cause fatigue, and general aches and pains. Testing is only recommended for people who are at high risk of deficiency -
those over 50,
people at high risk of falls or known osteoporosis
those with dark skin or modest dress
all pregnant women
and also for babies, breast-feeding mothers and children who also have high risk factors.
Supplements are then recommended for all pregnant women with low levels, for breast-fed babies of women who are known to be deficient, and for adults or children at high-risk with confirmed deficiency.
So what do you do, if you now know you are at low-risk, but have already had testing and were found to be mildly Vitamin D deficient? Well, because the health implications of your low levels are not clear, current recommendations are not to re-test or take supplements but to focus on lifestyle changes - maintain adequate sun exposure, eat a balanced, calcium-rich diet and maintain good bone health through regular weight-bearing exercise.
