Monday, March 12, 2012

Nutrition ABCs: Vitamin D

Many moons ago, I thought it would be cool to start a little encyclopedia of nutrition terms I wanted you all to know more about. I made it to the letter C. Ahem...onward and upward! I think it is time to pick up this little theme once again. Nutrition is getting no less confusing...and we are still a wee bit unhealthy as a society. Just sayin'.

I started the Nutrition ABCs in 2010. A was for anti-oxidants; b was for broccoli and c was for now we are on to d. Which, of course, means we must chat about vitamin D!

The news on vitamin D seems to have cooled off as of late; just a few years ago you could hardly pick up a magazine or turn on the news without seeing a story on vitamin D. And rightly so: long dismissed as simply the ugly best friend of calcium in the quest for bone health, vitamin D finally got to stand out in the spotlightWhat has changed since my last post on vitamin D? Well, the Institute of Medicine and Health Canada did indeed change their recommendations on vitamin D. What was the cutting edge of the research is becoming accepted nutritional fact: we need more vitamin D. Health Canada now recommends 600IU for those aged 7 - 70. The upper limit, or amount at which there is no foreseen risk of daily use, has been doubled to 4000IU. Again, most vitamin D experts would consider this conservative. 

So what will vitamin D actually do for you? Research is growing in the areas of heart health, cancer prevention, prevention of type 2 diabetes and auto-immune diseases and even weight loss. However, some of the challenges with this research (especially in the initial stages) include ineffective dosing and lack of placebo-controlled, double blind trials. However, the evidence is considered substantial enough for many in the world of health and research to call for a widespread increase in intake. 

While called a vitamin, vitamin D is actually more biologically similar to a steroid hormone once activated by the kidneys. It has an effect on almost every organ and tissue in the body and helps to modulate the immune system. This is one of the most interesting outcomes of vitamin D intake to me; considering all of the attention on chronic inflammation in the progressive health literature, keeping the immune system tuned is important. And most of us have not been getting enough vitamin D. Ideally, your physician would assess your blood levels of vitamin D so you can be dosed accordingly. In the absence of that knowledge, a safe bet for almost all adults would be 2000-3000 IU of vitamin D3 a day. As mentioned in my previous post, you can't really rely on most food sources (except for fatty fish like salmon) for an effective dose. As a dietitian, I don't like people to pop pills unnecessarily; however, I routinely recommend vitamin D to my clients. 

PS. Read my opinion...and then discuss it with your health professional. This post is offered as information only; this article can't take the place of in person consultation with a qualified health professional. And no, I don't have a financial stake in any supplement company. I just want you to be healthier!

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