Yawn: Vitamin D Deficiency Linked to Daytime Sleepiness

SHREVEPORT, La.Feeling a little sluggish during the day? You might want to reach for a glass of milk or vitamin D fortified snack. A new study published in the Journal of Clinical Sleep Medicine found individuals who are vitamin D deficient are more prone to daytime sleepiness compared to those who have adequate vitamin D levels.

Researchers from Louisiana State University examined serum 25-hydroxyvitamin D (25OHD) levels of 81 sleep clinic patients who complained of sleep problems and nonspecific pain. Those with 25OHD levels less than 20 ng/mL were determined to have vitamin D deficiency. Sleepiness was determined using the Epworth Sleepiness Scale score.

In patients with vitamin D deficiency, the lower the vitamin D levels, the more daytime sleepiness they experienced. In black patients, mean excessive daytime sleepiness scores in patients with vitamin D deficiency were higher and 25OHD levels were lower.

Patients with normal vitamin D levels also benefited from higher levels. In these patients, higher levels of daytime sleepiness were associated with lower levels of vitamin D.

The researchers found excessive daytime sleepiness was directly correlated with 25OHD in black patients with vitamin D deficiency, but not Caucasian patients with vitamin D deficiency. The higher the vitamin D levels they had, the more likely they were to have daytime sleepiness, showing the vitamin/sleep relationship is complex.