Vitamin D & endothelial function

Area of Science:

• Endocrinology
• Cardiovascular Science
• Nutritional Science

Background:

• Vitamin D deficiency is linked to obesity, cardiovascular disease (CVD), and type 2 diabetes.
• Endothelial dysfunction is a potential mechanism underlying insulin resistance and CVD risk.
• Extra-skeletal roles of vitamin D are gaining research interest.

Purpose of the Study:

• To review recent randomized controlled trials (RCTs) investigating the causal link between vitamin D supplementation and endothelial function.
• To assess the impact of vitamin D on vascular reactivity and markers of inflammation.

Main Methods:

• PubMed search (2009-present) for RCTs on vitamin D supplementation and direct endothelial function measures.
• Inclusion criteria: English language, Jadad score ≥ 3.
• Ten high-quality RCTs were selected and their outcomes summarized.

Main Results:

• Only two studies demonstrated improved flow-mediated dilation with vitamin D supplementation.
• Three studies reported reductions in specific inflammatory markers (C-reactive protein, PAI-1, t-PA, BNP).
• Overall, recent high-quality RCTs did not support a beneficial effect of vitamin D on vascular reactivity.

Conclusions:

• Current evidence from rigorous RCTs does not confirm vitamin D's benefit for endothelial function.
• Future studies should explore higher vitamin D dosages and longer intervention durations.
• The potential regulatory role of vitamin D in endothelial function requires further investigation.