There does seem to be a growing consensus within the scientific community that not only are many in both the UK & US suffering from chronically low vitamin D levels1,2,3, but that vitamin D also could affect muscular performance4,5. Bear in mind that 'vitamin' D is actually a hormone & the term vitamin is actually inaccurate. There also appears to be receptors both in muscles & the genes themselves for vitamin D, this could have an effect on injury & training6,7,8. It has also been noted that low vitamin D levels affects the infiltration of fat into muscle tissue (how that could affect performance isn't really understood at all yet!)9. As well as the fat in muscles at least one study has found an inverse relationship to various bodyfat measurements (as well as BMI), so the lower the vitamin D levels, the higher the fat in at several ethnic groups10. One thing that may affect this fat level association with vitamin D is the apparent concordant levels of vitamin D & androgenic hormones in the body11, that is as vitamin D levels go up in the summer, so do a persons androgen levels, at least in males (in females I'm not sure this has been tested?). It is not totally proven that it is vitamin D or some other factor that raises androgenic levels in the males tested, so it's not a totally proven theory, but not worth dismissing either. There is also yet another interesting use of vitamin D for the athlete. Vitamin D is an anti-inflammatory12 & so can aid in recovery (all exercise causes inflammation, to recover from exercise the inflammation must be allowed to recover & the tissue has to have time to rebuild just a little more strongly than before, that is the basic idea of how it is thought we build muscle). So, having a high level of vitamin D may speed up the recovery process?
We are not going into the beneficial effects outside of athletic performance here, but it should be noted that high vitamin D levels have been linked to lessening the chances of autoimmune disease, lessening the chances of cancer, lessening the chances of disease generally & improved overall health (avoiding all of the aforementioned is probably a good idea for any athlete I would have thought)
So, when you take an overview of vitamin D & it's possible effects on muscular performance, injury reduction, effects on hormone levels,body composition effects & general overall health benefits, I'd say that you don't really have any reason not to take some precautions to make sure you are getting enough. If you feel you are getting enough I would suggest that you get a vitamin D test, these days they are cheap (get the 25 OH Vitamin D test there are others that don't show how much active vitamin D you have in you).
Lastly I will just add (putting on my nutritionist hat) to try to eat foods that contain vitamin K. So eat your greens everyday for vitamin K1, but just as important think about finding a vitamin K2 source - natto is my choice for vitamin K2 as vitamin K2 works with vitamin D. Also foods containing magnesium are vital for proper vitamin D usage & so are the things like boron, zinc & vitamin A (eat foods high in β-carotene to get all the vitamin A you need). Lastly, there is some concern about whether to use vitamin D2 or vitamin D3, I did talk a little about that issue here, but it isn't a referenced piece as it was basically just reviewing a product, not the sort of piece to clog up with references. I personally have moved over to the vegan form of vitamin D3 simply because some studies say vitamin D2 & vitamin D3 are the same, while others say vitamin D3 is superior, but none say that vitamin D2 is superior, so having vitamin D3 at the least is the same as having D2, while it 'could' have added benefits, so the choice is yours. If you would like me to look into the whole vitamin D2 Vs vitamin D3 thing with a referenced piece covering all the whys & wherefores then post a quick reply below & I will do it for you.
So, if you are like me, in the western world & still in winter, then NOW is the time to get vitamin D if you have not been taking it as you have been out of the sun for months now & your levels will remain very low until summer comes & you get out in the rays (to get vitamin D though you need to be without sunscreen, so if you wear sunscreen or avoid the sun then vitamin D is doubly important for you!).
Two companies that sell vitamin D (& just to make the point I get nothing for saying this, I have just used both these companies at some point) are vitashine who sell the new vitamin D3 (made from algae & vegan society approved), you can get either a spray (5 squirts equal 1,000IUs of vitamin D) & a 5,000IU pill formulation, the other company is viridian vitamins who make a vitamin D2 1,000IU pill formulation. As I said both these companies are one's I have used & both make excellent products.
Last warning please check if getting vitamin D3 pills or sprays as vitashine is the only company I know making guaranteed vegan vitamin D3, every other company get their vitamin D3 from animal sources, so double check before buying vitamin D3 (saying 'vegetarian' will usually still mean the vitamin D3 comes from an animal source, so be warned!).
References:
1/ Solar UV doses of adult Americans and vitamin D3 production
2/ Diet, environmental factors, and lifestyle underlie the high prevalence of vitamin D deficiency in healthy adults in Scotland, and supplementation reduces the proportion that are severely deficient.
3/ Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin.
4/ Vitamin d and athletic performance: the potential role of muscle.
5/ Athletic performance and vitamin D.
6/ Vitamin D and athletes.
7/ Vitamin D and its role in skeletal muscle.
8/ Vitamin D and Human Skeletal Muscle.
9/ Vitamin D Status and Its Relation to Muscle Mass and Muscle Fat in Young Women
10/ Association of Plasma Vitamin D Levels with Adiposity in Hispanic and African Americans
11/ Association of vitamin D status with serum androgen levels in men
12/ Vitamin D status, 1,25-dihydroxyvitamin D3, and the immune system
4 comments:
You may also include this article by Dr. Mercola. Great lecture about vitamin d - http://articles.mercola.com/sites/articles/archive/2008/12/16/my-one-hour-vitamin-d-lecture-to-clear-up-all-your-confusion-on-this-vital-nutrient.aspx
I do not like Dr Mercola (not personally - I don't know the guy, but the reputation). He follows the same tactics as the Weston Price Foundation. He speaks some truth, but some lies. He has had FDA warnings issued against him & generally for him it is all about selling product & making cash. He is an unreliable source of information & he lies as it suits him (but always with enough facets of truth to lead the unwary in). I wouldn't pick Dr Mercola as your source of information in my opinion. Places like pubmed or google scholar show you the actually abstracts from research & you can read them yourself. At first they can be hard to understand as they use specific terminology, but after a while (& some help from google), you can begin to read them & understand the terminology with relative ease! Also if you live near a library you can often get the journals & read the full studies (or if you are a student - or know a student systems like athens allows you to view full studies online for free).
I haven't view this piece, it may be accurate or it may be more of Dr Mercola's half-truths, but looking at the title he rarely 'clears up confusion' he usually generates it in my opinion.
I've only been taking vitamin D3 for a few days now (1000 IU), but I already feel increased muscle tone. It's pretty remarkable. I think it's decreased my appetite as well. I wonder if that effect will continue.
I hope it does. Remember resistance training is still the best source of obtaining 'muscle tone' & if you check out vitashine they have both a 1,000IU spray & 5,000IU pills (personally I do the pills)
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