By Dayne Hudson
What role if any, does vitamin D have on your muscle growth?
Does a little time in the sun help with your gains?
Some research out of Thailand sheds some interesting light on this (pun intended).
It examined 163 overweight but healthy men and women, looking at the amount 25-hydroxyvitamin D in their blood. They also measured their body composition.
Thailand is obviously a tropical country with plenty of sun, but still, most of the study subjects had quite low vitamin D levels in their blood.
What the researchers found was the subjects with higher of vitamin D in their blood were the ones who had a lower fat percentage, and also more muscle mass.
These findings are also consistent with other research that's found high body fat is frequently accompanied by low vitamin D levels.
So how can someone who lives in a tropical country have low vitamin D levels?
Well, because as your body becomes fatter, the skin surface area actually increases LESS than your mass does.
So the amount of sun that your skin can suck up and the level of vitamin D that your body can synthesise – doesn't increase at the same rate of your bodyweight.
This is simply why they suggest that if you have MORE vitamin D you'll most likely have MORE muscle mass and less fat!
I THOUGHT THIS STUDY MEANT I COULD GET MORE SUN FOR MORE GAINS?!
Well this just might be the case!
The researchers think that a higher level or vitamin D could just help us achieve more muscle mass.
In in-vitro studies (eg in a lab and not in humans), when scientists expose muscle cells to vitamin D, they have the ability to grow (3).
Furthermore, research into rats has found muscles cells that don't get enough vitamin D break down muscle proteins quicker - not what we want (4).
So it seems pretty clear - don't get too fat during a bulking phase, and enjoy a bit of sun in moderation.
It may be serving your gains well!
"Stay Fit, Stay Flexed!"
REFERENCES
(1) Chattranukulchai Shantavasinkul P et al. Vitamind D status is a deerminant of skeletal muscle mass in obesity according to the body fat percentages. Nutrition. Published Online: December 18, 2014.
(2) Vimaleswaran KS et al. Causal relationship between obesity and vitamin D status: bi-directional Mendelian randomization analysis of multiple cohorts. PLoS Med. 2013;10(2):e1001383. doi: 10.1371/journal.pmed.1001383. Epub 2013 Feb 5.
(3) Garcia LA, Ferrini MG, Norris KC, Artaza JN. 1,25(OH)(2)vitamin D(3) enhances myogenic differentiation by modulating the expression of key angiogenic growth factors and angiogenic inhibitors in C(2)C(12) skeletal muscle cells. J Steroid Biochem Mol Biol. 2013 Jan;133:1-11. doi: 10.1016/j.jsbmb.2012.09.004. Epub 2012 Sep 12.
(4) Bhat M, Kalam R, Qadri SS, Madabushi S, Ismail A. Vitamin D deficiency-induced muscle wasting occurs through the ubiquitin proteasome pathway and is partially corrected by calcium in male rats. Endocrinology. 2013 Nov;154(11):4018-29. doi: 10.1210/en.2013-1369. Epub 2013 Aug 8.
