Vitamin D is a hormone that is produced in your skin when it is exposed to ultraviolet light from the sun when you go outside. Deficiencies in vitamin D are prevalent in countries that don't get much sunlight and can cause a severe disease known as Rickets. Vitamin D is also important for developing and maintaining healthy bones. Milk and other food sources these days are fortified with added vitamin D so that everyone gets their daily required amount. Vitamin D deficiency is on the rise because people do not get enough sun and are missing it from their diet.

Knowing how good this hormone is for the body, researchers have now found another reason that vitamin D is so vital for a healthy body. A link between the levels of vitamin D and muscle efficiency was seen in a study that found that it may also be effective in improving overall muscle function.

Researchers used a non-invasive MRI scan to test the levels of phosphocreatine, a chemical important in the production on energetic ATP molecules inside of the mitochondria (or power plants) of every cell.

By looking at the levels of phosphocreatine in the calf muscles of patients who suffered from severe vitamin D deficiency before and after vitamin D treatment they were able to see the effect of the treatment after exercise.

The team found that the phosphocreatine recovery increased significantly after Vitamin D treatment for 10-12 weeks. The time it took for the chemical to be replenished went down, on average, from 34.4 seconds to 27.8 seconds. And all patients reported improvements in symptoms such as fatigue, after the treatment.

This is the first time that vitamin D has been linked to muscle efficiency and that it works through increasing the mitochondria's ability to replenish phosphocreatine. Although the researchers do not know the exact route that the hormone helps mitochondria, the research group hopes to explore the trend in detail in future studies.

This avenue of research may eventually help the elderly or frail who have muscle weakness problems and may be found to be a useful boost for athletes.

The report published in the journal Endocrine Abstracts can be found here.