The recommended daily allowance for vitamin K for healthy males aged 19 to 30 is a 120 micrograms per day. For females aged 19 to 30 years old, it's 90 micrograms a day. Vitamin K is a great supplement because it promotes proper blood clotting, prevents bleeding and hemorrhages and also helps improve bone density, so it's a great way to prevent osteoporosis. One additional benefit of vitamin K is that it can prevent the hardening of the arteries, which can lead to heart disease and heart failure. Some great natural sources of vitamin K include dark leafy greens such as kale, collards, and broccoli, olive oil, avocado, strawberries, beans, and eggs. If for some reason you're not getting enough vitamin K from your natural food sources, it's a good idea to consider taking vitamin K in a supplement form, that way you make sure you're getting everything you need.