Supplementing with vitamin D? What you should know

In this 2-minute video, Dr. Alexandra Papaioannou discusses how to safely supplement with vitamin D and the risks associated with excess amounts.


What's the bottom line?

  • Taking 800 to 1,000 international units daily for three months is sufficient for most people to support muscle and bone function. 
  • Greater than 4,000 international units can be associated with high levels of calcium in your blood, cause kidney stones, and there are some signals that it may be linked to cancer. 
  • Consult your primary care provider or pharmacist before starting supplementation with any fat-soluble vitamins, like vitamin D.

Learn more about the role vitamin D plays in the function of your body and how to get a healthy daily dose of vitamin D by watching the full-length video.

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This work is supported through the McMaster Institute for Research on Aging and funds provided by the Dean and Vice-President, Faculty of Health Sciences at McMaster University.

DISCLAIMER: These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (

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