What about sunshine?
Vitamin D is known as the sunshine vitamin for good reason. Exposure to sunlight triggers the synthesis of Vitamin D in the body. In fact, natural sun can produce 20,000 IU of Vitamin D in only about 20 minutes of sun exposure when the sun is ‘high in the sky’. While the body can only use a portion of this, it can be stored for times when we don’t make Vitamin D.
Two factors may hinder our ability to derive Vitamin D from sunlight, which is its natural source. For those living in northern climes, winter sunlight exposure is often insufficient to produce significant amounts of it. And during the warmer months, use of sunscreen can prevent our bodies from replenishing its stores. If you use a sun protection factor (SPF) of 8 or greater, you block your body’s ability to synthesize sunlight into Vitamin D, according to the US National Institutes of Health (NIH).
In fact, in contrast to years of advice to apply sunscreen before going outdoors, short periods of unprotected sun exposure can be beneficial to your health, experts now say. The key is moderation. 10-15 minutes of exposure to the face, hands or back is usually enough to provide sufficient vitamin D, according to the NIH.
This is by no means an invitation to return to the free-wheeling days of ‘shake and bake’. The initial 10-15 exposure to sunlight should be immediately followed by application of sunscreen with an SPF of at least 15 to avoid risk for skin cancer, experts say.
Fast facts about Vitamin D
The only natural foods containing Vitamin D are egg yolk, liver and fatty fish, such as salmon, tuna, mackerel and sardines. It is also found in fortified foods such as some cereals and beverages such as milk, margarine and soy milk.
Vitamin D is available over the counter in 1,000 IU pills or drops.
Are you Vitamin D-deficient? A simple blood test — the 25(OH) D or calcidiol test — can indicate if your Vitamin D level is low.
Sources: American Society of Clinical Oncology; Health Canada; Multiple Sclerosis Resource Centre; Vitamin D Society; US National Institutes of Health; Mayo Clinic.
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