Although known by a common name, vitamin K actually consists of a family of important compounds that feature the same chemical structure. These include phylloquinone, or vitamin K1, and menaquinone, which is also referred to as vitamin K2.
Vitamin K is used to produce a protein known as prothrombin. Made in the liver, prothrombin is one of several factors believed to promote proper blood clotting and many associated health benefits.
A fat-soluble nutrient, vitamin K can be found in several types of food. As with many types of vitamins, it is best absorbed when eaten alongside healthy sources of dietary fat such as olive oil.
If consumed regularly as part of a well-balanced diet, this vitamin can provide several health benefits for the body’s cardiovascular and skeletal systems.
Why You Need Vitamin K
While vitamin K deficiency is rare, it’s still important to strive for a diet rich in this nutrient, as it delivers benefits ranging from effective clotting to reduced risk of osteoporosis. Broken down quickly by the body, this vitamin is unlikely to reach toxic levels, even when consumed in high amounts.
The average daily amount of Vitamin K you need varies by your age and sex. Women ages 19 and older need about 90 micrograms per day, while men ages 19 and older need 120 micrograms.
Vitamin K is important for a variety of body systems, including:
Vitamin K’s letter comes from the term “koagulation,” as the vitamin was first discovered at the Biochemical Institute of the University of Copenhagen.
While researching a coagulation disorder in chicks, Carl Peter Henrik Dam realized that the hemorrhaging could be resolved with vitamin K. Today, experts still regard vitamin K as essential for healthy clotting.
A diet rich in vitamin K can promote bone strength. Research suggests that people who eat foods rich in this vitamin are less likely to develop osteoporosis, a condition which weakens the bones and makes them brittle.
Preliminary research suggests that people who do not consume enough vitamin K may be at a greater risk of developing coronary heart disease. This may occur in response to narrower or stiffer blood vessels feeding the heart.
Foods With Vitamin K
Vitamin K is found in a variety of foods, including several common types of produce. This makes it easy to eat a diet rich in this important vitamin. These eight foods contain especially high levels of vitamin K:
Popular in Japan, this fermented soybean is one of the richest sources of vitamin K available. Just 3 ounces of natto contain 708 % of the recommended daily value. Specifically, natto features a subset of vitamin K known as menaquinone or vitamin K2. Researchers believe that this is the most potent form of the vitamin.
While many types of green vegetables contain high levels of vitamin K, it is particularly prominent in collards. If boiled from frozen, half a cup contains 442 % of the recommended daily value.
- Turnip Greens
While turnips offer a variety of health benefits, their greens are also worth eating. If prepared from frozen by boiling, turnip greens can deliver 426 micrograms in just half a cup. Turnip greens can also be eaten raw, sauteed, or braised.
If you’re looking for an easy way to increase vitamin K intake, add some spinach to your salad, sandwich, or smoothie. It may not contain as much as collards or natto, but a cup of spinach should provide more than the recommended total amount of vitamin K you need in a day.
Widely regarded as a superfood, raw kale contains 113 micrograms of vitamin K per one-cup serving. Kale is also rich in vitamin A and vitamin C, as well as calcium, potassium, and several other important nutrients.
- Carrot Juice
While carrot juice is best known as a source of beta-carotene, it also provides an impressive amount of vitamin K. To pack an extra punch, add both carrot juice and spinach to a smoothie.
- Soybean Oil
A surprising source of vitamin K, soybean oil delivers over one-fifth of the recommended daily value with just one tablespoon. For a double dose of the vitamin, use soybean oil to create a dressing for spinach, kale, or other leafy green vegetables.
- Organ Meat
Other than natto, the menaquinone form of vitamin K2 is primarily found in animal products. Organ meat can be an especially rich source of this nutrient.