The Wonders of Vitamin D3

We’ve known about the benefits of vitamin D3 for a long time now, and I’ve been using it in my practice pretty much from the beginning.  But some of the new research published about its preventative benefits is simply astounding.

For example, having an optimal level of vitamin D in your blood can lower the risk of breast cancer by 83%, ovarian cancer by 17%, colon cancer by 60%, kidney cancer by up to 49%, endometrial cancer by 37%, and non-Hodgkins lymphoma by 18%.  And it’s not just good for cancer prevention, proper blood levels of vitamin D can lower the risk of diabetes by 66%, reduce fractures by 50%, drop multiple sclerosis risk by up to 54%.  Vitamin D also reduces the risk of falls by 72%, and the risk of heart attack by 30% (Grassrootshealth).  It also reduces muscle weakness and soreness, seasonal affective disorder (the winter blahs), and reduces premature delivery.  And finally, it improves the body’s ability to fight off colds and flu (Beard, Sundaram), among many other benefits.

The key to all these benefits is having an optimal blood level of vitamin D, which is in the range of 100-150 nmol/L (or 40-60ng/mL) of 25-hydroxycholecalciferol.  Ideally 135 nmol/L.  Research shows that  most normal adults are in the 25 to 50 nmol/L range.  In the summer, being outside regularly can be sufficient to bring your vitamin D levels to optimum, but during the Canadian fall, winter, and spring the strength of the sun’s rays is insufficient.

That leaves food and vitamin supplementation.  Vitamin D can be found in foods such as orange juice (50 IU per cup), milk and milk alternatives like rice, almond, or soy milks (88 to 123 IU per cup), eggs (57-88 IU per 2 eggs).  The biggest food sources are fish, ranging from 60 IU (tuna) to 699 IU (salmon) per 75g (2.5 oz) (Dieticians of Canada).  The amount of vitamin D3 consumption required to achieve optimal blood levels of vitamin D varies from 400 to 4000IU or more per day, making intake from food difficult.  To complicate matters further, there is no standard dose.  Some people require more and others less vitamin D per day to achieve ideal blood levels.

The most important part of the vitamin D story, is to ensure you have optimal blood levels.  Too little will hamper the beneficial effects, while too much can lead to side effects.  Blood vitamin D levels are checked at our office with a simple blood test.  It is not usually covered by OHIP, but costs only $30.  The price of the test has recently gone down, and I’ve found that some insurance companies even cover it now.


GrassrootsHealth, Disease Incidence Prevention by Serum 25(OH)D level, a handy chart with numbers.

Beard JA, Bearden A, Striker R. Vitamin D and the anti-viral state, J Clin Virol. 2011 Mar;50(3):194-200. doi: 10.1016/j.jcv.2010.12.006. Epub 2011 Jan 15. Review.

Sundaram ME, Coleman LA. Vitamin D and influenza, Adv Nutr. 2012 Jul 1;3(4):517-25. doi: 10.3945/an.112.002162. Review.

Dieticians of Canada. Food sources of vitamin D.

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