Vitamin D – needed supplement
Your skin makes vitamin D when sunlight hits it. That works well here in July. It does not work in January.
Why Canada is different: almost all of the country lies far enough north that from roughly October through March the sun sits too low for our skin to make meaningful vitamin D — and the further north you live, the longer that stretch lasts. Calgary sits at about 51 degrees north, so here it runs a good half of the year. Add long sleeves, indoor work and short daylight, and most of us are relying on food and supplements through the winter.
Who tends to run low: people who spend little time outdoors even in summer, people with darker skin (melanin reduces vitamin D production), adults over 65, people who cover most of their skin, anyone with a condition affecting fat absorption such as coeliac or Crohn disease, and people who have had weight-loss surgery. Breastfed infants need a supplement as well — your doctor or public health nurse will go through this with you.
Food sources that help: fatty fish such as salmon, trout and sardines; egg yolks; and in Canada, milk and margarine, which are fortified by law. Many plant-based drinks are fortified too — it is worth checking the label, because not all are.
What low vitamin D feels like: often nothing at all, which is why it goes unnoticed. When symptoms do appear they are vague — tiredness, aching muscles, low mood, bone discomfort. Those symptoms have many other causes, so they are a reason to talk to your doctor rather than to assume vitamin D is the answer.
About testing: a blood test can measure your vitamin D level, but it is not recommended for everyone, and in Alberta it is not routinely covered unless there is a specific medical reason — for example osteoporosis, a malabsorption condition, or certain medications. Your doctor can tell you whether testing would change anything in your case. For many healthy adults it would not.
About supplements — the numbers: Health Canada’s recommended daily intake is 600 IU (15 µg) for adults up to age 70, and 800 IU (20 µg) from 71 onward. Separately, Health Canada advises everyone over 50 to take a 400 IU supplement each day in addition to what they get from food.
Osteoporosis Canada frames it by risk rather than age alone: 400–1,000 IU a day for healthy adults under 50, and 800–2,000 IU a day for adults 50 and over, for anyone at higher risk, and for people living with osteoporosis.
More is not better. The tolerable upper intake level for adults is 4,000 IU a day. Sustained doses above that can raise your calcium level and cause harm. Talk to your physician about where in these ranges you belong — particularly if you take other medications, or have kidney problems or a condition affecting calcium.
Speak to a doctor sooner if you have bone pain with muscle weakness, repeated fractures from minor knocks, or a child with delayed walking or bowed legs. These are uncommon, but they need proper assessment rather than a supplement bought off a shelf.
If you are not sure whether any of this applies to you, bring it up at your next appointment — it takes a minute to sort out, and it is a sensible thing to settle before winter is fully under way.
Please note: this article reflects current medical guidance at the time of its last review (August 2026). Medical recommendations change as new evidence emerges — for the most up-to-date advice about your own health, always talk to your health-care provider, or call Health Link Alberta at 811. This information is general education, not personal medical advice. © Grace Medical Clinic, Calgary.
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