Why Vitamin D Supplementation Shouldn't Stop Come Summer

I’m big on Vitamin D3. While it’s often heralded as a bone-building micronutrient, its functions don’t stop there. Vitamin D helps us to fight infections, is integral to our cardiovascular health, may prevent cancer, and impacts our brain development as well as muscle function. According to the Vitamin D Council, a deficiency in this key vitamin can lead to conditions ranging from cancer to asthma to depression. Autoimmune conditions, type II diabetes, Crohn’s, MS, and Alzheimer’s may result, too. Vitamin D3? She’s a power player in the nutrition world and typically underrated.

There’s much debate about how much Vitamin D3 to take (and yes, take — it’s basically impossible to get enough from food and sunlight if you live in Canada). I like and use these guidelines in practice, though I’ll admit they’re still fairly conservative; more research is required in this area to determine optimal dosage.

Now that the warmer weather is upon us, it seems like an apt time to discuss Vitamin D3 supplementation — and why it shouldn’t stop when the parkas come off. In the past I often recommended people supplement for 6 months on and 6 months off, but I’ve since revised my stance on D3 and suggest it be taken consistently throughout the year due to the various reasons explained below.

Why? Well, while your skin is certainly able to manufacture Vitamin D3 through sun exposure, many of us spend our summers huddled away in offices, walking around in suit jackets or long sleeves, or covered in sunscreen (screen blocks most Vitamin D production.) Most of my corporate clients rarely make it outdoors, save perhaps for at night or on weekends. Trust me when I say this is simply not enough time. Sunny office? Glass blocks out UVB rays, so you won’t be able to produce Vitamin D even if you feel the warmth of the sun from your desk.

Another important point: it gets increasingly challenging to produce enough Vitamin D as you age, as the skin has a more difficult time synthesizing.  As our world becomes more and more polluted, it will become even more difficult to obtain enough Vitamin D from the sun. “Polluted air soaks up UVB and reflects it back into space” according to the Council, which means if you live in a busy urban environment with a lot of pollution, you’ll have a tougher time meeting your Vitamin D needs. And although you can get a sunburn on a cloudy day, less UVB will reach your skin, making the amount of D you produce less than optimal.

If you’re unsure of how much Vitamin D3 (D2 for vegetarians and vegans) to take, I highly recommend going for a blood test. This will give you a baseline. Though it takes a lot of Vitamin D3 to reach toxicity, it’s still a fat-soluble vitamin and gets stored in the body. Those with pale skin require less than those with dark skin, as they can produce D more quickly. For more information on this topic, please consult the Vitamin D Council website or a qualified healthcare professional.

Sarah Berneche

Sarah Berneche, 14 Denison Square, Toronto, ON, M5T 1K8