You are here: 

Vitamin D

Vitamin D is needed for healthy bones and muscles, especially in children and the elderly. There is also evidence that vitamin D may reduce the risk of some types of cancer, particularly colorectal and breast cancers. Your skin produces vitamin D when exposed to sunlight, but you don’t need a tan to get benefits from the sun.

The amount of sun exposure needed to produce enough vitamin D depends on:

  • age
  • diet
  • skin colour
  • where you live
  • how strong the sun is

For most people, just a few minutes out in the sun – the short, casual exposure you get while going about daily life – will be enough. Even with the benefits of vitamin D, we recommend that you still practice SunSense.

Getting your vitamin D from your diet (many foods are fortified with vitamin D) or by taking vitamin supplements is safer than UV-ray exposure.

  • Our recommendation

    Due to our northern latitude and because the sun’s rays are weak in the fall and winter, talk to your doctor about whether taking 1000 international units (IU) a day during fall and winter months is right for you.

    Babies who are exclusively breast-fed may be at risk of vitamin D deficiency, which is why experts recommend they be given a vitamin D supplement of 400 IU a day.

    Who’s at higher risk?

    You’re probably not getting enough vitamin D if you:

    • are over 50
    • have dark skin
    • don’t go outside very much
    • wear clothing covering most of your skin

    If you are in one of these groups, talk to your doctor about whether you should take a vitamin D supplement of 1000 IU every day, all year round.

    Can you have too much of a good thing?

    We don’t recommend taking any more than this amount because too much vitamin D can be harmful. Current evidence suggests that taking this amount will help reduce your risk of cancer but with the least chance of harm.

  • Getting the right amount of vitamin D

    For most adults, taking a supplement of 1000 IU a day won’t be a problem. But there is most likely an optimal range of vitamin D – having either too little or too much can cause health problems.

    Side effects of too much vitamin D

    The most common side effect of having too much vitamin D is high calcium levels, called hypercalcemia. Some early symptoms of hypercalcemia include:

    • nausea
    • vomiting
    • poor appetite
    • weakness

    Talk to your doctor if you are experiencing any of these symptoms.



Marj and Chloe Poirier If it were not for the Society, I’m not sure how we could have managed.

Read Chloe's story

Taking action against all cancers

Icon - question mark

The latest Canadian Cancer Statistics report found that of all newly diagnosed cancers in 2017, half are expected to be lung, colorectal, breast and prostate cancers. Learn what you can do to reduce the burden of cancer.

Learn more