Vitamin D supplementation and major cardiovascular events: D-Health randomised controlled trial.

Researchers randomly gave 21,315 Australian adults aged 60 to 84 either a monthly vitamin D pill or a placebo, a look-alike pill with no active ingredient. The vitamin D dose was 60,000 international units each month for about five years. Researchers tracked major cardiovascular events, meaning heart attacks, strokes, and procedures to restore blood flow to the heart. These events happened slightly less often in the vitamin D group, but the difference was small enough that it could have happened by chance.

What this means for you: For preventing heart attacks or strokes, this study does not give a good reason to buy vitamin D supplements. Vitamin D may still be useful for people who are deficient or have another medical reason to take it, but this trial did not show a clear heart benefit.