Mitochondria are your power plants. They generate adenosine triphosphate or ATP. ATP is often called the “molecular unit of currency of intracellular energy.” If you have fatigue, or are easily fatigued, it may be that your mitochondria are not making enough ATP.
I have written before about the effects of vitamin D on mitochondrial function, but in rats not humans.
George N, Peeyush Kumar T, Antony S, Jayanarayanan S, Paulose CS. Effect of vitamin D3 in reducing metabolic and oxidative stress in the liver of streptozotocin-induced diabetic rats. Br J Nutr. 2012 Jan 6:1-9.
Now, Doctor Akash Sinha working under the supervision of senior author Professor Tim Cheetham, just released a remarkable human study.
Sinha A, Hollingsworth KG, Ball S, Cheetham T. Improving the vitamin D status of vitamin D deficient adults is associated with improved mitochondrial oxidative function in skeletal muscle. J Clin Endocrinol Metab. 2013 Mar;98(3):E509-13.
Twelve individuals with severe vitamin D deficiency (< 6 ng/ml) who presented with fatigue and/or muscle cramps underwent mitochondrial testing at baseline and then again after vitamin D supplementation. They administered, 20,000 IU every other day for 12 weeks. Their mean vitamin D levels increased from about 4 ng/ml to about 45 ng/ml in 12 weeks.
The mitochondrial test they used (31P-MRS ) is a test of multiple mitochondrial functions. Their test of oxidative phosphorylation (a measure of ATP production) improved significantly (p=.001), achieving the same 31P-MRS as normal controls.
The authors concluded:
“In conclusion, these data show that cholecalciferol therapy in symptomatic, vitamin D-deficient individuals results in improved mitochondrial oxidative function as measured by 31P-MRS.”
I admire the dose they used, essentially 10,000 IU/day. In order to prevent under dosing in scientific studies, such doses are needed lest the scientists miss a treatment effect.