Ep 222 Vitamin K: Calling the shots

In 2017, a baby named Olive was born. She was breathing, her heart was beating, but she was otherwise non-responsive. Doctors found blood in the fluid from a lumbar puncture. A pediatric intensivist asked Olive’s mother a question that stopped her cold: had they given Olive a vitamin K shot at birth? They had not. The lack of vitamin K meant Olive’s blood could not clot. A bleed had developed in her brain, destroying the water pockets within it and damaging the tissue on the left side. The clot was placing immense pressure on her brain. The mother later wrote: “What happened to her was nearly 100% preventable. And yet it happened.”

A Vitamin That Does One Critical Thing

Vitamin K is a fat-soluble vitamin, meaning the body needs dietary fat to absorb it and can store small amounts. It isn’t a single substance: vitamin K1 (phylloquinone) comes from leafy greens and vegetables, while vitamin K2 (menaquinones) is produced by bacteria in the human gut and found in fermented foods like cheese and natto. But for all its forms, vitamin K does essentially one biochemical job. It acts as a cofactor for an enzyme that adds a carbon dioxide molecule to glutamic acid, a process called carboxylation. This is the finishing touch that activates a family of proteins known as GLA proteins. Without vitamin K, these proteins cannot take their final active form.