CWeak evidence, or evidence againstVitamin
The short answer
The bone and artery claims run well ahead of the trial evidence. The warfarin interaction is the part that actually matters.
Who this is actually for
People on long-term vitamin K antagonists should not self-supplement. Otherwise, deficiency is uncommon.
What it is legally allowed to claim
Quoted from the EU register of authorised health claims, Regulation (EU) 432/2012. A product may only make these claims if it supplies enough of the nutrient to qualify.
- Vitamin K contributes to normal blood clotting
- Vitamin K contributes to the maintenance of normal bones
How much is too much
No EFSA upper level established.
Cautions and interactions
Interacts directly with warfarin and other vitamin K antagonists, changing INR. Never start without telling the clinic that monitors you.
Ask a pharmacist before you start anything. Interactions with prescribed medicines are the most common way supplements cause harm, and they are easy to check. Bring the actual packet, or a photo of the ingredients panel, because doses and forms vary enormously between products. Nothing here is a substitute for advice about your own situation.