Vitamin K isn’t a vitamin that people commonly talk about.  But vitamin K is a very important vitamin and should not be discounted because it’s not as common in the minds of people, as for instance vitamin C or the family of B complex vitamins.

Vitamin K is actually a group of derivatives, with several notable forms of vitamin K.  K1 can be formed by natural bacteria in the intestines, and is the principal dietary source of vitamin K.  Vitamin K2 is the collective term for a group of vitamin K compounds called menaquinones.  Vitamin K2 is found in chicken egg yolk, butter, cow liver, certain cheeses and fermented soybean products such as natto. Very little vitamin K is stored by the body; small amounts of this vitamin are deposited in the liver and in the bones, but this amount is only enough to supply the body's needs for a few days.

The primary known function of vitamin K is to assist in the normal clotting of blood, but it may also play a role in normal bone calcification. Without vitamin K, the process called carboxylation does not occur and the proteins that are synthesized are biologically inactive.  In other words, without vitamin K, the chemical reaction performed at the cellular level, through the wisdom of the body, cannot take place.  The chemical reaction of vitamin K works to bind or join with calcium in an effort to build strong bones.  This biochemical reaction takes place in the liver.  Vitamin K also is required for proteins to function in the body, and this calcium binding power allows proteins to come together (or coagulate) upon injury—in other words, it tells the body to stop bleeding.

A 2001 study out of Switzerland (Vitamins and Fine Chemicals Division, Human Nutrition & Health, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland) speaks to the importance of vitamin K and bone health.  Researchers tell us that vitamin K plays a significant role in human health, beyond the well-established and necessary function in blood clotting.

Researchers indicate that there is consistent evidence in human studies that clearly demonstrates that vitamin K can improve bone health. These studies have demonstrated that vitamin K not only can increase bone mineral density in osteoporotic people, but vitamin K can also help to reduce fracture rates.  These studies provide evidence that vitamins K, along with vitamin D—a classic in bone metabolism—works synergistically on bone density.  While many of these studies used rather high doses of vitamin K(2), there is emerging evidence in human studies that vitamin K(1) at a much lower dose may also benefit bone health, in particular when supplemented with vitamin D.  There is increasing evidence that vitamin K also positively affects calcium balance, a key mineral in bone metabolism. The Institute of Medicine recently has increased the dietary reference intakes by approximately 50% from previous recommendations; but talk to your health care provider, since recommended doses vary per person, based on gender and overall need—especially if you’re taking a blood thinner.

The recommended daily dose of vitamin K for adults is 90 micrograms for females and 120 micrograms for males. While vitamin K deficiencies are rare, individuals with liver disease or metabolic disorders are at risk.  Since vitamin K is fat-soluble, its absorption is enhanced by dietary fat. Supplement vitamin K food sources with a moderate amount of fat. For example, add some butter to your cooked greens.  Leafy green vegetables are excellent sources of vitamin K. Broccoli, asparagus, cabbage, celery, beans, okra, lettuce, kelp and rhubarb are all rich in vitamin K. Eat plenty of fresh or frozen greens.  Enjoy salad dressing on your salad; since the fat in the dressing helps absorption, it is also a good source of vitamin K.  Alfalfa seeds are another, healthier source of vitamin K.  Spice up your veggies to increase their vitamin K content. Oregano, pepper and cloves are rich in vitamin K.

Vitamin K deficiency is rare and occurs when there is an inability to absorb the vitamin from the intestinal tract. Vitamin K deficiency can also occur after prolonged treatment with oral antibiotics.  It is often the result of impaired absorption rather than not getting enough in the diet.  Prolonged use of antibiotics can also cause a low level of this vitamin because they destroy some of the bacteria in the gut that help to produce vitamin K.  Newborns are at risk for vitamin K deficiency.  This is because their digestive tracts contain no vitamin K-producing bacteria.  While deficiency in adults is rare, when it occurs, it is found in people with diseases that prevent the absorption of fat. These diseases include cystic fibrosis, celiac disease, and cholestasis. Symptoms of vitamin K deficiency include bruising easily, epistaxis (nosebleed), gastrointestinal bleeding, menorrhagia (an abnormally heavy and prolonged menstrual period at regular intervals), and hematuria (blood in the urine).

So while vitamin K may not be a vitamin people are very familiar with, it is a vital vitamin to the health and density of our bones, as well as the role it plays in the necessary function in blood clotting.

By Cindy Gray