Vitamin D supplementation is associated with improved modulation of cardiac autonomic tone in healthy humans

Vitamin D Status, Autonomic Nervous System Activity, and Cardiometabolic Risk

“…They found a significant suppression of ANS balance in vitamin D deficient (25(OH)D < 20 ng/ml) participants at baseline, but no difference was observed during the challenge. In an intervention study, the same group demonstrated that healthy adults supplemented with 10,000 IU of vitamin D for four weeks had a significant improvement in cardiac ANS balance, specifically in enhancing the cardio-protective PNS activity [13]. In our study, we found that vitamin D insufficient participants had significantly lower RMSSD, HF, and TP values, all of which are indicators of PNS activity meaning that vitamin D insufficient participants had less cardioprotective PNS activity during the cardiac autonomic tests.…”

“…Vitamin D can permeate the blood-brain barrier and bind to VDRs located in extremely high concentrations in the midbrain and brainstem where some autonomic nervous system (ANS) neurons are located [10] [11]. Recent studies in healthy and diseased populations have found an association between vitamin D status and cardiac ANS function, with vitamin D deficiency related to cardiac ANS imbalance, more specifically with decreased parasympathetic nervous system (PNS) activity [2] [12] [13] [14]. The ANS is a branch of the peripheral nervous system that controls involuntary processes throughout the body like cardiovascular activity [15].…”

“…Thus, vitamin D may play a role in vascular health by participating in the control of vascular tone and blood pressure via indirect ANS activity or directly affecting the endothelium. These findings suggest that vitamin D may contribute to CVD risk by orchestrating genomic and non-genomic regulatory activity at the vascular level and higher brain centers of the ANS [2] [12] [13].…”

Vitamin D Deficiency and Cardiovascular Risk: we’re still in the Dark

“…This characteristic imbalance in HRV has been associated with the increased risk of SCD in this patient population [15,16]. Interestingly, observational studies have shown evidence of a link between vitamin D deficiency and abnormal HRV in humans both with and without CKD [17,18], as well as an improvement in HRV responses to a vascular stressor following 4 weeks of intensive oral vitamin D supplementation [19]. These findings suggest that vitamin D may play a role in regulating the activity of the cardiac ANS, and therefore may directly impact cardiovascular and SCD-specific risk to some degree in humans.…”

“…Because 1,25-dihydroxy vitamin D is produced mainly in the proximal tubules of the functional kidneys and it therefore chronically low in patients with CKD [20], this data would suggest that activated vitamin D concentrations may drive the observed relationship between vitamin D deficiency and increased cardiovascular risk via the disruption of cardiac ANS regulatory function. Lending to this thought, the aforementioned observational studies also showed that cardio-protective parasympathetic activity was dramatically restored only in subjects who achieved the highest quartile of 1,25-dihydroxy vitamin D levels after 4 weeks of oral supplementation [19].Clinical trials to assess the plausible causal relationship between low 1,25-dihydroxy vitamin D and cardiac ANS activity as a surrogate marker of cardiovascular risk are far and few between. Results of one completed study, the VITAH Trial, have not yet been published [22].…”