Vitamin K: The unfamiliar vitamin from the bunch

Vitamin A. Vitamin C. Vitamin E. We hear about all these vitamins every day. How vitamins are the micronutrient foundation for growing bodies, how they help boost the immune system and how they keep our bodies healthy. But there is one vitamin that not many people know about because the deficiencies in this vitamin are very rare. That vitamin is Vitamin K.

I had heard a little about this vitamin through my Dad’s conversations about his hospital days. I also watch a ton of the TV show “House” and on one episode; Dr. House was treating someone with a Vitamin K deficiency and it lead to some strange diagnosis, just like all of his diagnosis.

Worldwide, only a handful of researchers study vitamin K—long known for its critical role in blood clotting. But with the aging of the U.S. population, this vitamin may command a bigger following as its importance to the integrity of bones becomes increasingly clear. It activates at least three proteins involved in bone health. According the USDA, Americans consumed several times the recommended dietary allowance for vitamin K. But improved analytical methods show that the vitamin isn't as abundant in the diet as once thought. The RDA is 65 µg (micrograms) per day for adult females and 80 µg per day for adult males. Excellent food sources of vitamin K include: Brussels sprouts, spinach, swiss chard, green beans, asparagus, broccoli, kale and mustard greens. Very good sources include green peas and carrots.

Anyways, so what is Vitamin K and what does it do? Vitamin K1, also called phylloquinone, is the natural, plant form of this nutrient. Vitamin K2, also called menaquinone, is produced by the bacteria in animal and human intestines. Vitamin K3, also called menadione, is the synthetic version. The three forms are about equally helpful for blood clotting, but vitamin K1, the form that only occurs in green plants, is the best form for protecting against osteoporosis. A lot of research has been done using vitamin K3 even though this form is not allowed in nutritional supplements because of its history of serious adverse reactions.

Blood clotting is a vital function in the body that solidifies blood to prevent us from bleeding to death when a blood vessel is damaged either from an external wound or internally. Another benefit of blood clotting is that it secludes the area of an infection or injury and begins the healing process. Vitamin K is best known as being required for blood to clot. Interestingly, it is also required to activate several proteins that decrease blood clotting. Thus, research is showing that vitamin K not only helps to initiate blood clotting, but it is also necessary for its complex regulation.

Fifty-five percent of Americans over the age of 50, or 44 million people, have osteoporosis. This condition of low bone mass will cause 1 out of every 2 women and 1 out of every 4 men over the age of 50 to have a fracture in her/his remaining lifetime. Researchers are finding increasing ways in which vitamin K helps maintain bone mass.

A study of more than 70,000 women found that women who consumed larger amounts of vitamin K in their diets had a lower risk of hip fracture. Other studies have looked at the amount of vitamin K circulating in women's blood and found that low levels were associated with lower bone mineral density and higher fracture rates. Additionally, vitamin K appears to be important for the formation of cartilage and dentine, part of teeth.

Vitamin K levels appear to decrease with age while the risk of fracture increases. Therefore, it is important for older individuals to include foods containing vitamin K in their diet. In addition to supplying vitamin K1, leafy green vegetables are rich sources of other nutrients important for bone health: calcium and boron. That makes leafy greens especially important for people who do not consume dairy products, since dairy products are a major contributor of both calcium and boron in the U.S. diet.

Vitamin K is a pretty important part of our diet, just like all vitamins. So eat your veggies!