(NaturalNews) Low levels of vitamin D may be to blame for some cases of chronic sleepiness, according to a pair of recent studies by researchers from Louisiana State University.
Vitamin D is produced naturally by the body upon exposure to the ultraviolet radiation in sunlight. It is known to play an important role in bone health, as well as in regulating the immune system.
In the first study, published in the Journal of Clinical Sleep Medicine, researchers measured vitamin D and sleepiness levels in 81 patients at a sleep clinic. All participants had complained of both trouble sleeping and of "nonspecific pain." They were all eventually diagnosed with some sleep disorder, the most common being obstructive sleep apnea.
The researchers found that for most participants, sleepiness increased as blood levels of vitamin D decreased. The opposite effect was seen in African-American participants, however, with sleepiness increasing along with levels of vitamin D.
"While we found a significant correlation between vitamin D and sleepiness, the relationship appears to be more complex than we had originally thought," lead researcher David E. McCarty said. "It's important to now do a follow-up study and look deeper into this correlation."
Supplementation cures sleepiness
In a second study, due to be presented at the 25th annual meeting of the Associated Professional Sleep Societies in June, McCarty examined data on 153 sleep clinic patients who were enrolled in a study on sleep disturbances and had complained of chronic pain. The researchers found that 54 percent of the participants were vitamin D deficient, while another 30 percent had blood levels of the vitamin that were classified as insufficient but not yet deficient.
The findings were not surprising, because prior research had shown that low levels of vitamin D deficiency are often associated with a diffuse form of musculoskeletal pain, called osteomalacic myopathy, that can interfere with sleep.
Because osteomalacic myopathy is known to respond well to treatment with vitamin D supplements, the researchers prescribed supplements to study participants. Many of the participants did then experience a complete end to their daytime sleepiness symptoms. This suggests that vitamin D deficiency may actually be directly causing sleepiness, the researchers noted, perhaps due to its role in regulating inflammation in the body.
"More research is needed to define whether vitamin D deficiency mechanistically contributes to excessive daytime sleepiness and to determine if supplementation offers a novel method for alleviating it," McCarty said.
McCarty noted that his research has already led to changes in the ways that he treats patients with sleep disturbances.
"The way this study has changed my practice patterns comes from the realization that patients who present for complaints of possible sleep disorders are often vitamin D-deficient," he said.
"Therefore, in the patients I see as a sleep medicine specialist, I tend to screen for vitamin D deficiency in patients who complain of nonspecific musculoskeletal pain, and I recommend supplementation for levels below 30 ng/mL."
He suggests that other clinicians adopt similar practices, pending further research.