How much vitamin D do you need?

A new study at the University of Calgary is taking a look at how much of the sunshine vitamin is required to build and maintain strong healthy bones.

Vitamin D is known as the sunshine vitamin because our skin creates it when it is exposed to sunlight but many people are confused when it comes to knowing how much of the supplement to take.

Health Canada recommends 600 IU daily for adults up to age 70 and 800 for those older than 70.

Other health sources say people at risk of osteoporosis, should take between 800 and 2000 IU of vitamin D per day.

Researchers Steven Boyd and David Hanley are studying the vitamin and are looking to find a definitive answer to the question, how much is enough?

The pair will look into how much vitamin D is required to build and maintain strong healthy bones.

"There are currently no large-scale, high quality studies that look at the relationship of bone strength and vitamin D dose," said Boyd. "This study will provide evidence that will help people determine how much vitamin D is appropriate for their bones."

The study is the first of its kind and is hoping to recruit 300 volunteers between the ages of 55 and 70. 

Participants will be randomly streamed into one of three arms of the study:

• One hundred volunteers will receive a daily dose of 400 IU of vitamin D
• Another one hundred volunteers will receive 4,000 IU of vitamin D
• The remaining one hundred volunteers will receive 10,000 IU of vitamin D

Study participants will have both their bone density and strength measured by the world's first XtremeCT2 machine, located in the Bone Imaging Laboratory at the University of Calgary.

“We have a unique opportunity to look at very detailed pictures of the bone and what is going on with the bone as we increase or decrease the vitamin D dose. No one has really been able to establish what clearly is the best dose of vitamin D. We have a pretty good idea that it’s at least 400 units a day in addition to what we get in our diets but there remains controversy as to whether that is just adequate and whether there’s more benefit in taking a higher dose,” said David Hanley.

Chris Lunn broke his foot skiing and says he didn’t realize that the vitamin had such a profound effect on bone health.

“They’ve given me a bottle of vitamin D and I take five drops every day, about the same time, and I don’t know what the dosage is and neither do the people who are testing me,” said Lunn. “And they’re going to measure my bones, they’ve taken a baseline measuring my ankle and wrist at the beginning of the study, and they’re going to check up on that over time and see what impact vitamin D has on my bones.”

The double-blind study will track study participants over the next three years and also look into other benefits of vitamin D, such as quality of life as it relates to mood and depression.

To participate in this study, contact the Vitamin D Study Team by e-mailing:  [e-mail]  or by calling 403-220-3888.