Vitamin K: What It Does, Who Needs It, and Why It Matters

When you think of vitamin K, a fat-soluble nutrient essential for blood clotting and bone metabolism. Also known as phylloquinone (K1) or menaquinone (K2), it’s not something most people think about—until they’re on blood thinners or have trouble healing after a cut. Unlike vitamin C or D, vitamin K doesn’t get much attention, but it’s quietly keeping your body running. Without it, even a small scrape could bleed longer than it should. But here’s the twist: vitamin K does more than just help your blood clot. It also tells your bones to stay strong and keeps calcium out of your arteries.

People on long-term proton pump inhibitors, medications used to reduce stomach acid often don’t realize they’re at risk for vitamin K deficiency. These drugs lower stomach acid, which messes with how your body absorbs fat-soluble vitamins—including K. Same goes for antibiotics: they wipe out the good gut bacteria that make vitamin K2. And if you’re taking warfarin, a blood thinner that works by blocking vitamin K’s activity, your intake needs to be steady. Too much vitamin K can make warfarin less effective. Too little? That’s when you risk dangerous clots.

Most people get enough vitamin K1 from leafy greens like spinach, kale, and broccoli. But vitamin K2, which comes from fermented foods like natto or cheese, is the one that really helps your bones and heart. Studies show people who eat more K2 have fewer calcium deposits in their arteries and lower rates of bone fractures. If you’re older, on antibiotics, or have digestive issues, you might need more than what your diet gives you. And if you’re taking any medication that affects your liver or gut, vitamin K could be quietly working behind the scenes—sometimes helping, sometimes hurting.

That’s why the posts here cover everything from how vitamin K interacts with blood thinners to why people on long-term acid reducers might need to watch their levels. You’ll find real advice on spotting deficiency, understanding what your doctor might miss, and how to talk to your care team about supplements without risking side effects. No fluff. Just what you need to know to stay safe and healthy.