When you think about vitamins, you probably think of vitamin C for colds or vitamin D for bones—but vitamin K, a fat-soluble vitamin essential for blood clotting and bone metabolism. Also known as phylloquinone and menaquinone, it’s the quiet hero that keeps you from bleeding too much after a cut and helps your bones stay strong as you age. Most people get enough vitamin K from their diet, but if you’re on blood thinners like warfarin or have digestive issues, even small gaps can cause real problems.
Vitamin K1, the main form found in leafy greens is what your body uses to make clotting factors. You’ll find it in huge amounts in kale, spinach, collard greens, and broccoli. Vitamin K2, a different form made by bacteria and found in fermented foods and animal products, plays a bigger role in directing calcium to your bones instead of your arteries. That’s why natto (fermented soy), sauerkraut, cheese, and egg yolks matter—not just for flavor, but for long-term health.
Here’s the thing: vitamin K doesn’t just show up in one food and call it a day. It works with other nutrients. Low vitamin K can make warfarin harder to manage, which is why people on blood thinners are often told to keep their intake steady—not avoid it. And if you’re taking antibiotics long-term, your gut bacteria might not be making enough K2, which can quietly lower your levels. Magnesium and vitamin D also help vitamin K do its job, which is why deficiencies in any of these can stack up and mess with your bones or circulation.
You don’t need supplements unless a doctor says so. Most people get what they need from a few servings of dark leafy greens a week. A single cup of cooked kale has more than 1,000 micrograms—over 1,000% of your daily need. That’s more than you’ll find in any pill. But if you’re eating a lot of processed food, skipping vegetables, or have a condition like Crohn’s or celiac, you might be running low without knowing it.
What you’ll find in the articles below are real, practical connections between vitamin K and other health issues you might not expect: how it interacts with blood thinners like warfarin, why it matters if you’re on antibiotics, and how even your sleep or chronic pain could be tied to low levels. These aren’t generic lists—they’re deep dives into how vitamin K shows up in real life, in real people, and what you can actually do about it.
