The Effect of Vitamin D Supplementation of Circadian Rythms and Sleep
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Authors
Gray, Ryan; Ravn, Mike
Issue Date
2025-04-03
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Abstract
Description
Vitamin D is an essential vitamin and hormone that the body either makes or obtains from
food. It plays a crucial role in physiological functions, such as calcium homeostasis, bone
mineralization, and immune support. Previous literature also provides indirect evidence
suggesting a possible link between vitamin D and circadian rhythms. For instance, vitamin
D is produced in response to the primary circadian influencer, sunlight. It is also
fundamental for melatonin production, the sleep-wake hormone, and has receptors located
in the ‘circadian center’ of the brain (suprachiasmatic nuclei). However, no known
research has been done studying the effect of vitamin D on circadian rhythms. Thus, the
aim of this study is to see if vitamin D supplementation alters circadian rhythm parameters
and sleep. Participants between the ages of 18-80 were recruited to supplement with 4000
IU of vitamin D for 4 weeks. Data on circadian rhythms (amplitude, acrophase, mesor),
objective and subjective sleep, and subjective mood were collected pre- and post supplementation. No significant differences were observed in circadian parameters, but
there were changes in sleep and mood. Specifically, overall time slept decreased from pre
(463.8 ± 102.7 min) to post (423.0 ± 80.4 min; p=0.03), subjective sleep quality increased
from pre (5.8825±2.40) to post (4.55±2.30; p=0.01), and self-reported depression scores
decreased from pre (3.95±3.37) to post (2.95±3.69; p=0.02). The data suggests that 4000 IUs
of Vitamin D is not effective in improving circadian rhythms. However, that amount of
vitamin D is sufficient for altering sleep and mood.