Efficacy of low‐fat milk and yogurt fortified with encapsulated vitamin D(3) on improvement in symptoms of insomnia and quality of life: Evidence from the SUVINA trial

INTRODUCTION: Sleep disorders are a common condition globally. Vitamin D receptors are present on cells in several regions of the brain. It is possible that vitamin D status may affect brain function, including sleep patterns. We aimed to evaluate the 1,500 IU of Nano‐encapsulated vitamin D fortified in dairy products on the symptoms of insomnia and associated improvement of quality of life. METHODS: A case series was undertaken as part of the Survey of ultraviolent intake by nutritional approach project. Subjects enrolled among adults with abdominal obesity. Twenty‐nine subjects with insomnia were selected according to the results of Insomnia Severity Index questionnaire and quality of life using a Short Form Health Survey (SF‐36) questionnaire. Subjects were allocated to four groups: low‐fat milk fortified by 1,500 IU vitamin D(3) (n = 8), simple milk (n = 8), low‐fat yogurt fortified by 1,500 IU vitamin D(3) (n = 7), and simple yogurt (n = 6) and were treated for 10 weeks. RESULTS: The insomnia score improved after the intervention in the group receiving vitamin D fortified milk compared to group receiving unfortified milk (p < .001). There were no significant differences between the two groups taking yogurt (fortified vs. unfortified). Comparison of quality of life scores between baseline and after intervention indicated significant improvements in both fortified and simple milk groups (p = .002 and p = .03, respectively); but no differences were found in the groups taking yogurt. CONCLUSION: Fortified low‐fat milk containing 1,500 IU vitamin D(3) can improve insomnia symptoms and subsequently quality of life. Trial registration number: IRCT20101130005280N27, www.IRCT.ir.