Many apologies for my last weeks absence from Fitness Friday, you see here was my week…
Midterm number 1 Tuesday + Group assignment due for clinical 2
Midterm 2 on Friday morning (Keep in mind that Tuesday and Thursday are full days on campus aka very lil study time)
Midterm 3 (CLINCIAL aka extremely dense material) Tuesday, where I could only start studying following my Friday midterm.
Every day basically went like this..
Get up, eat, study, gym, school, study, eat, study, etc, bed. Repeat for 1.5 weeks.
Did my body hate me after that period…? 1000% yes. I retained so much water which I’m still trying to be patient about it coming off and my digestion has been messed for the past week.
Stress my friends, stress is a problem.
Obviously burnt the candle from both ends and overall burnt out in the end. Thankfully, although I, and all the nutrition students, was a complete zombie come Tuesday, I have managed to pull off an 88 in one and a 90 in another, so at least I get some reward from working my ass off.
Okay now that I have cleared my mental space all over you, lets get on with today’s topic…
Yes, the “sunshine vitamin“
Did you know that a huge number of athletes are deficient in this vitamin and that is has been linked to deficits in athletic performance?
Before I go on, here a quick fact sheet on the sunny vitamin:
~It is fat soluble and is thus best absorbed in the body if taken with fat.
~It’s technically also a hormone. It plays a role as a steroid hormone though working to activate
~The active form, 1,25-dihydroxyvitamin D (or calcitriol) is synthesized in the kidneys and released to respond to decreasing serum calcium levels.
~Most of a persons daily needs of vitamin D can actually be made if you get adequate sunning time as it is converted endogenously from UV light. This is with the help of the liver. Of course, most of use don’t get enough real sun time due to fear of skin cancer and being in places that doesn’t give adequate sunlight throughout the year
~One of it’s most important functions is helping with the absorption of calcium in the intestines.
~It is used for more than just bone health, but has also been linked to immunity, growth, and reduction of inflammation.
If you want more facts, visit here.
Okay so you say that many athletes are deficient in it?
A recent study (2015) presented at the Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) found that more than 1/3 of their elite collegiate athlete sample had insufficient levels of vitamin D. Moreover, greater risk was associated with being male and having darker skin tones.
This isn’t just an American issue though, many northern latitudes have also found similar issues. This study presented a few studies of athletes in other countries from Finland to France to Germany who also showed drastically high levels of inadequacy in their elite athletes.
Why is this important?
As mentioned above, yes it is a concern for bones and overall health, but what about in athletic performance, as it is Fitness Friday after all?
Numerous studies have found impaired performance in athletes who were deficient.
~This study gave a great highlight reel of studies showing how UV radiation improved performance in athletes. The research dated back into the 1930’s and continues to show a seasonal variation in performance that follows a similar pattern as vitamin D levels. Basically, greater activation of the active form of vitamin D occurred during times when there sunlight was greater and more people were taking that sunlight in. So peak training took place during the summer months and a sharp decrease was shown in the fall and winter months.
~This review gave a great presentation of the role of vitamin D in the muscle.
~This study, among many others, suggested that athletes may require higher than normal levels of vitamin D to support performance and recovery. Furthermore, a safe dose of radiation therapy may be beneficial, but more research is needed.
Overall, despite a lot of research on why low vitamin D levels could contribute to performance and recovery deficits, the research in supplementation with athletes is minimal and mixed. Perhaps they need higher doses of supplements as supplemental forms do not get as well absorbed in the body? This could be a good guess as these have been numerous studies showing that UV light (which enables more endogenously created vitamin D) increases performance and that is the form that is most related to circulating vitamin D.
So how can I make sure I get enough?
Another quick fact is that the majority of your vitamin D that contributes to circulating serum levels is not from you diet. In fact, there is quite a shortage of foods that contain vitamin D and the actual amount of that you absorb is not that great.
Most of us here in Canada are deficient, in the winter time especially, and so supplementation is always recommended on top of trying to get in some sources from food. Overall, all methods that include ingesting sources are not the best at reaching your targets so the best idea is simply to try to get a bit of all sources. Some sun, some food (natural sources + fortified) and take a good supplement.
Foods highest in Vitamin D
~Fatty, cold water fish (mackerel, sardines, etc)
~Fortified sources like dairy and even some juices like O-J are also fortified. NOTE that being a fat soluble vitamin, you best bet is to buy full fat dairy sources.
***NO this is not bad for you. Fat is not bad for you. It is simply more calorically dense, which should leave you feeling more satisfied and fuller. Sorry had to get that out of the way.
For you supplement route..
If you take a daily fish oil (one of my top recommendations), most of those contain a good dose of vitamin D. For example, cod liver oil is a great choice. I will also say liquids first, try to avoid capsules for fish oils or pure vitamin D supplements. The sublingual forms of vitamin D, those that go under the tongue, often come in flavours these days and fish oils have come a long way as well. No excuses folks, just chuck them back.
So what is my take on all of this?
It appears to be too early to tell whether performance can be enhanced with a supplement. It may be that supplements are just not absorbed well enough to present any benefit for athletic performance or it could be that athletes just need more. That is unclear. What I will say that is that regardless, I still recommend a supplement to help you out because most of us Canadians and Americans are deficient and there are umpteen other health benefits of vitamin D that are important to consider.
Well that’s it for tonight friends!
Happy start to your weekend 🙂
Do you take a vitamin D supplement?