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Evidence-Based Supplement Research
Evidence-Based Supplement Research
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Big effect

Vitamin D halved the risk of post-surgery atrial fibrillation in heart bypass patients who were truly deficient — but showed no benefit for those with milder insufficiency.

This is a large, precisely measured effect in a specific clinical population, but it's one of the first studies on this pairing. The finding likely applies only to vitamin D deficient individuals undergoing coronary artery bypass grafting — not to the general public or even to heart surgery patients with normal vitamin D levels. Notably, the same meta-analysis found the supplement did not shorten hospital stays or reduce time on a ventilator, suggesting the benefit is narrow.

In a meta-analysis of 694 coronary artery bypass patients with low vitamin D, those who took vitamin D before surgery were roughly half as likely to develop new atrial fibrillation afterward — a common and dangerous heart rhythm complication. The effect was large and statistically solid, but only appeared in patients who were outright deficient; those with milder insufficiency saw no benefit. The caveats: the studies were unblinded, other important outcomes like hospital stay length didn't budge, and this is an early finding that needs replication before we know how broadly it applies.

Where this fits in the evidence

This is among the first studies we've indexed on Vitamin D for Reduced Postoperative Atrial Fibrillation — treat it as an early signal until more research accumulates.

The study

Role of vitamin D supplementation in prevention of new onset atrial fibrillation in post-coronary artery bypass graft patients in vitamin D deficient and insufficient populations: a systematic review and meta-analysis.

  • Meta-Analysis
  • n = 694
  • 2025-10-17
  • BMC cardiovascular disorders
More on Vitamin DMore on Reduced Postoperative Atrial Fibrillation

This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.

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