A new study led by Dr Akash Sinha from Newcastle University has shown that vitamin D is vital for making our muscles work efficiently and boosting energy level.

Vitamin D is a hormone normally produced in the skin using energy from sunlight. It can also be found in a few foods – including fish, cheese, butter, egg yolks and fortified cereals, but it can also be effectively boosted with Vitamin D supplements.

Dr Sinha’s team used non-invasive magnetic resonance scans to measure the response to exercise in 12 patients with severe deficiency before and after treatment with vitamin D.

“The scans provided a unique window into what is really going on in the muscle as it works,” said Dr Sinha, who with colleagues reported the findings in the Journal of Clinical Endocrinology & Metabolism.

“Examining this small group of patients with vitamin D deficiency who experienced symptoms of muscle fatigue, we found that those with very low vitamin D levels improved their muscle efficiency significantly when their vitamin D levels were improved.”

Alongside poor bone health, muscle fatigue is a common symptom in vitamin D deficient patients. This fatigue could be due to reduced efficiency of the mitochondria: the ‘power stations’ within each cell of the body.

Mitochondria use glucose and oxygen to make energy in a form that can be used to run the cell – an energy-rich molecule called ATP. Muscle cells need large amounts of ATP for movement and they use phosphocreatine as a ready and available energy source to make ATP. The mitochondria also replenish this phosphocreatine store after muscle contraction and measuring the time taken to replenish these stores is a measure of mitochondrial efficiency: better mitochondrial function is associated with shorter phosphocreatine recovery times.

The team found that these recovery rates significantly improved after the patients took a fixed dose of oral vitamin D for 10-12 weeks. The average phosphocreatine recovery half time decreased from 34.4 sec to 27.8 sec. All patients reported an improvement in symptoms of fatigue after having taken the supplements. In a parallel study, the group demonstrated that low vitamin D levels were associated with reduced mitochondrial function.

“We have proved for the first time a link between vitamin D and mitochondria function. Of the patients I see, around 60% are vitamin D deficient and most people living north of Manchester will struggle to process enough vitamin D from sunlight alone, particularly during winter and spring. So a simple vitamin D tablet could help boost your energy levels – from within the cells,” Dr Sinha concluded.

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Bibliographic information: Akash Sinha et al. 2013. Improving the Vitamin D Status of Vitamin D Deficient Adults Is Associated With Improved Mitochondrial Oxidative Function in Skeletal Muscle. The Journal of Clinical Endocrinology & Metabolism, vol. 98, no. 3, E509-E513; doi: 10.1210/jc.2012-3592