If our vitamin K levels drop too low, though the threshold varies from person to person, we can spontaneously bleed internally. It activates the molecules (clotting factors) that allow our blood to clot.

Vitamin K is a fat-soluble vitamin that’s actually named after what it does: Koagulation, the German word for coagulation. Much of this information is available is also covered in the book Emily Willingham and I wrote, The Informed Parent: An Evidence-Based Resource for Your Child’s First Four Years, and the study references are available here. The best antidote to fear, misinformation or a general lack of information is knowledge, so let’s review the basics of what vitamin K is, why it’s needed and what it does-and doesn’t-do. The reasons range from faith-based ones to beliefs that it’s “unnatural” to anxiety about pain and possible side effects.

Now a new study in the Journal of Medical Ethics explores the reasons that somewhere between 0.5% and 3% of parents decline the shot.

Vitamin k antidote