The ABCs of Ds

Jennifer Sygo, National Post 


It's that time of year again. Time for soup, comfy sweaters, dead celebrity costumes and vast amounts of candy. For nutrition geeks, however, October is -- cue the music -- one of the most wonderful times of the year. It is, after all, the start of the vitamin D winter, and that means it's time to get out the old soap box and start preaching about the wonders of the sunshine vitamin that, if you live in the Great White North, is virtually impossible to generate through your skin as of mid-October. And since it's really tough to get much from your diet (significant amounts of vitamin D are naturally available from oily fish, or supplemented in milk, yogourt and margarine), that means now's the time to crack open the pill bottles as you whisk yourself away to an imaginary beach many miles away.

If you've been following this column for a while, you'll recall that this is not the first time that vitamin D has been brought up, nor will it be the last. Think of it as a rite of passage, something of a harbinger of fall. Because, with each passing year, the volume of evidence to support vitamin D's benefits for Canadians mounts, and so does the need to spread the word, far and wide, about this unsung hero of health.

You've seen the evidence ... or have you?

Depending on your devotion to health headlines, you might have picked up on some of the vitamin D news of late. But for those who might have missed it, here's an overview: After years of thinking that vitamin D's main role was in building and maintaining healthy bones, we now know that it acts in a number of ways previously unimagined. For a while, the big story was its potential role in cancer prevention, but a growing body of research has also linked vitamin D insufficiency to other chronic diseases, including heart disease and type-2 diabetes. More recently, connections between vitamin D status and cognitive decline, autism, chronic pain (including fibromyalgia -- some researchers believe that many cases of fibromyalgia may actually be misdiagnosed vitamin D deficiency) and depression have been suggested.

One particularly interesting -- and complex -- area being studied is the role vitamin D plays in maintaining a healthy immune system. The rise in autoimmune disorders such as type 1 diabetes, lupus, multiple sclerosis and rheumatoid arthritis -- all conditions where the body essentially turns on itself -- has lead researchers to ask the question, "Is our chronic lack of vitamin D making us sick?"

While the risk of autoimmune diseases goes up as vitamin D status goes down, the cause might be more complicated than a simple lack of sunlight. Instead, some scientists now believe that autoimmune diseases start when a bacterial infection disrupts our vitamin D receptors, which in turn causes vitamin D deficiency. The end result is an immune system thrown into flux. The weakened immune system then becomes more susceptible to more infections, and a vicious circle begins. While vitamin D supplementation seems to improve symptoms of many autoimmune diseases, the next question is how to prevent these infections, or reverse the damage they have caused.

Time to start knowing your numbers

Until recently, anyone wanting to know their vitamin D status was usually left in the dark. Now, a growing number of physicians and medical facilities are testing serum (blood) vitamin D -- known as 25-hydroxy vitamin D, or 25(OH)D -- opening the door for personalized recommendations to optimize health and potentially reduce the risk of a particular disease.

If you are able to get your 25(OH)D levels tested, it's generally accepted that you need to reach 75 nmol/L to offer reasonable protection from disease. If you're like many Canadians, however, your blood levels are probably hovering in the 30-60 nmol/L range, even after summertime fun in the sun.

While the response to vitamin D supplementation varies from person to person, you can use a rough rule that serum levels rise by 25 nmol/L for every 1,000 IU of vitamin D taken. That means that an individual with a 25(OH)D of 30 nmol/L would need about 2,000 IU to meet the current standard. Optimizing your vitamin D status (which many researchers believe occurs when serum levels are between 130-170 nmol/ L) might mean supplementing with even more, but for now, Health Canada says that the upper level is 2,000 IU.

Getting your Ds

One obvious way to get your vitamin D is via the sun, but that comes with the associated risk of skin damage and cancer. Moreover, those of Asian and African decent are less able to produce vitamin D through their skin, making the risk of deficiency even greater. Regardless, no matter who you are, once your shadow grows longer than you are -- which is the case even for the midday sun starting around this time of the year -- you can't produce any significant amount of vitamin D in your skin.

For most people, the easiest -- and safest -- way to get enough vitamin D is to pop a pill. Thankfully, vitamin D pills are cheap and easy to swallow (they're small). But for those who aren't into pills, liquid vitamin D drops are also available. These tiny drops disappear into food or drink, and are basically tasteless. Either way, taking your vitamin D with a small amount of fat will help with absorption -- and that could go a long way to improving your health.

- Jennifer Sygo is a dietician in private practice at Cleveland Clinic Canada (clevelandcliniccanada.com), which offers executive physicals, prevention and wellness counselling and personal health care management in Toronto.


