Vitamin K (K1 & K2)

Silver· human data

Also known as: Phylloquinone, Menaquinone, MK-7

Essential for clotting (K1) with emerging bone and arterial claims for K2.

Vitamin K1 (from leafy greens) is essential for blood clotting, an established and non-negotiable role. Vitamin K2 (menaquinones such as MK-7) helps direct calcium into bone and away from arteries.

The K2 bone and cardiovascular-health claims are biologically plausible and supported by early human data, but remain preliminary rather than proven. An important caution: vitamin K interacts with the anticoagulant warfarin, so anyone on it should keep intake consistent and take medical advice.

Sources

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Written and reviewed by Mathew Beale, MSc Biotechnology, University of Reading.

Last reviewed: