Wednesday, March 17, 2010

Vitamin K

Vitamin K is one of those vitamins that you don’t seem to hear a lot about in the media or in the doctor’s office. So what is vitamin K and why should you care about it?

Vitamin K is an important nutrient for heart and bone health. There are two natural forms utilized by the body, Vitamin K1 and K2. K1 is used for blood coagulation, while K2 is used for calcium regulation. Vitamin K2 is mostly found in meat, organ meats (liver), cheese, and egg yolks. With prevailing low-fat and vegetarian diets, many of us eat reduced amounts of meat and opt for egg white omelets, basically eliminating the richest source of this essential vitamin. As a result, many people may be deficient in K2. Natto, a fermented form of soy native to Japan, is an excellent source of K2, but is not common in the US. K1 is found in leafy greens such as kale, spinach, chard, broccoli, brussel sprouts, parsley and romaine lettuce. To get enough K1, however, you would need to eat an abundance of these foods daily, which unfortunately, most of us don’t do. K1 is also not very well absorbed by the body (usually about 10%, but absorption is improved when consumed in conjunction with fatty oils, so pour on that olive oil!). K2 is more absorbable, or bioavailable, for the human body. Both work together to prevent cardiovascular disease: K2 by controlling calcification in your arteries, and K1 by helping to thin the blood.

Calcification of the arteries is a form of cardiovascular degeneration that can begin at an early age but usually goes unnoticed until more serious problems arise as a result. K2 helps prevent this process by deciding where calcium gets delivered in the body. K2 ensures that the calcium you consume is deposited in your bones, not in your blood vessels and other soft tissues. Dr. William Davis explains, “Normal deposition of calcium occurs only in bone and in teeth. Abnormal deposition of calcium in the body occurs in three places: the inner lining of the arteries of the body (the intima) that causes atherosclerotic plaque; the muscle layer of arteries ("medial calcification"); and heart valves. K2 appears to be the form of vitamin K responsible for controlling these phenomena (not K1, the form that plays a crucial role in blood clotting).” It’s easy to see why Vitamin K2 is important in preventing heart disease and osteoporosis.

The Rotterdam Heart Study, consisting of 4800 participants, displayed the powerful association of vitamin K2 dietary intake and heart disease. Those who included the greatest quantity of vitamin K2 in their diet had 57% fewer heart attacks than participants who ingested minimum amounts. The same evidence was not true for vitamin K1. The lowest risk group included more than 32.7 mcg of vitamin K2 per day in their diet (mostly from cheese). In other studies, researchers found that vitamin K2 significantly reduced the risk of death from all causes by 26% and severe aortic calcification by 52%.

Without enough vitamin K (both K1 and K2), the vast majority of the population are at risk for age-related disease. Your arteries receive calcium they don’t need or want, and your bones become more porous since the calcium is not delivered to them. In men younger than 35, calcification of the aorta increased risk of sudden coronary death 7-fold. (Witteman JC, Kannel WB et al. Am J Cardiol 1990; Pohle K, Ropers D, et al. Heart 2003; Iribarren C, Sidney S et al. JAMA 2000)

In other research involving more than 100,000 men and women in California, aortic calcification increased risk of coronary heart disease 127% in men and 122% in women. Among women, it also increased risk of stroke 146%. (Iribarren C, Sidney S. JAMA 2000)

K2 also helps promote blood vessel elasticity by safeguarding elastin, the core protein in the muscle fibers primarily responsible for the elasticity of the arterial wall. Existing elastin is damaged and new production is inhibited by calcium deposition. (Seyama Y, Wachi H. J Athero Thromb)

If you are at risk for cardiovascular disease and/or osteoporosis, consider adding full spectrum Vitamin K supplementation to your diet. And if you are vegan or on a strict diet, it may be wise to consider K2 supplements. If you are not on a specific diet, consider enjoying pate as an appetizer or liver and onions for dinner. Adding some hard cheese to your diet, or a hardboiled egg for a fast breakfast may greatly improve your heart health and decrease your risk for osteoporosis.

You can read more about protecting your heart at

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