Here in Melbourne our winters are relatively mild, we tend to miss out on snow or frozen pipes, and are lucky enough to spend some time outdoors. Until recently conventional medicine largely viewed this nutrient as a co-factor for bone strength but in the last few years research has found its role to be much more diverse and vital. From promoting healthy brain function through to preventing some cancers, Vitamin D is the hottest kid on the block. Conversely, low Vitamin D may make you more susceptible to getting influenza and it can wreck your sleep patterns. Sunshine is a major source of Vitamin D but despite Australian being “the sun burnt country the majority of us are deficient in it. In 2005 The Medical Journal of Australia concluded that all Australians are “more likely to be deficient than not” in the vitamin and attributed the success of the Sun Smart campaign as being one of the contributing causes.
Other than the sunblock issue, when you actually look at how much sun exposure we need to get an adequate daily dose of this important nutrient in this city, it makes more sense why many of us are all so low in D. On a winter’s day in Melbourne you need to expose at least 15% of the body (e.g. face plus hands plus arms or legs) to sunlight for around 25 minutes at midday, or up to 52 minutes mid morning or mid afternoon. That figure is for Caucasians, the darker your skin the more sun you need (up to 4 times greater), that could make sunbathing a full time job. Considering the cloudy skies and chilly temperatures of late, this kind of daily sun exposure is very difficult to get. For a handy reference, see the sun exposure guide for Australian and New Zealand cities in the MJA article.
Other than soaking up UV light, you can eat more oily fish, though it is difficult to get accurate figures on the Vitamin D content of Australian fish due to the inadequacy of local food databases. The best types of local oily fish include mullet, sardines and mackerel. It is possible that canned wildwild salmon from the northern hemisphere contains more Vitamin D than our local fresh salmon which is mostly farmed. Some sources state canned tuna that is packed in water has no vitamin D; in oil it may have less than half that of tinned pink salmon. So maybe a sardine or salmon and salad sarnie for lunch in the sunshine is a good prescription to beat the winter blues.
Realistically though if your vitamin D levels are low, food and winter sunshine is unlikely to be enough to remedy this. It is worth requesting a blood test to check your Vitamin D next time you see the GP. If they are at the bottom end of the normal range or lower, I’d suggest an initial supplement regime of 2,000 iu twice a day for the first two weeks to, followed by a maintenance dose of 2,000 iu once a day until the summer solstice (late December). Vitamin D3 (the most effective form on Vitamin D) supplements are relatively inexpensive and available over the counter from health food stores, supermarkets and pharmacies.