Vitamin K is an important fat-soluble vitamin for normal vision, immune system, and reproductive health. It includes vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Vitamin K helps produce a protein called prothrombin in the liver, which aids in normal blood clotting. Foods rich in vitamin K include: 1. Kale 2. Spinach 3. Mustard greens 4. Broccoli 5. Brussels sprouts 6. Avocado 7. Olive oil 8. Natto. Vitamin K supports bone health, preventing osteoporosis, and may reduce the risk of heart disease. Adult women need about 90 micrograms per day, while adult men need 120 micrograms.