Recently, I seem to be hearing people talk a lot about the winter blahs. If you’ve been a little under the weather lately, if you’ve been feeling a little “draggy”, or if your energy is just not what it normally is and you can’t quite figure out why, it may be vitamin D deficiency.
Vitamin D is required for many bodily functions. Bone density and immune system function are a few important ones. In our bodies, vitamin D needs to be “activated” in our skin by exposure to the sun.
As a result, just about every Canadian will have low, if not insufficient, vitamin D levels at this point in the winter if they are not supplementing with vitamin D. The combination of very little sunlight, short days, and cold weather leave most of us indoors and without adequate sun exposure to produce enough vitamin D to maintain health. Consequently, our immunity is down and we get sick.
So we need to supplement – during the winter at the very least. But the controversial question is: how much do I need to take? Lots of patients tell me they are taking vitamin D in their multi vitamin. Almost without exception, a multi vitamin has inadequate vitamin D. It is usually in the neighbourhood of 500 or 1000 IUs (international units).
Recent research shows that clinical dosage of vitamin D begins in the range of 4000 IU/day. So if you are supplementing with less than this it is probably not helping. That being said, vitamin D is a fat-soluble vitamin. That means that you can take too much.
How do you get it just right? Well, you test it. A simple blood test done for two years in a row, twice per year (spring and fall) will give you a really good indication of how much you need to take to maintain healthy vitamin D levels based on your activity levels and life style.
I monitored my own vitamin D through our testing (its just a simple finger prick blood test) and discovered that I need to supplement in the winter but not in the summer. I spend a lot of time outdoors in the summer and can activate adequate vitamin D through natural sun exposure so no supplementation is required. In the winter, I need some. So I supplement with liquid vitamin D for six months of the year.
At the gym lately I have been overhearing many conversations about people being sick, or having low energy, or just feeling sluggish during their workouts. Some interesting research may offer insight for those of you CrossFit athletes or anyone who works out at relatively high intensity.
A 2014 Greek study of professional soccer players found that those with higher vitamin D levels in the blood had better muscle strength, sprinting capacity (based on measures of jumping ability and strength), and VO2 max (a measure of aerobic capacity). The researchers chose soccer athletes since the intensity and variety of activities in soccer is so diverse: sprinting, jumping, stopping, changing directions, pivoting (sounds a lot like a MetCon to me – for all you CrossFit athletes). They also found that vitamin D levels dropped significantly in these athletes when their training intensity picked up.
A similar study of soldiers found that high intensity combat training significantly lowered vitamin D levels – even in the summer. The take away point here is that if you are exercising at high intensity (like in CrossFit) you most likely need to supplement with vitamin D (probably throughout the entire year).
So if you are feeling draggy, experiencing low energy, or you can’t seem to increase your weights lately, you should look at proper vitamin D supplementation.
Hope that helps. Feel free to contact me if you have any questions.
Dr. Craig Dingman
PS. To learn more about proper nutrition, join us at our next Eat By Design workshop taking place on February 13th at 6:30pm.