Vitamin A, B, C, D, E...and K? Starting even with its name—you have to skip past F thought J to get to it—vitamin K seems out of place and until recently, it hasn't been very well-known. The "K" actually comes from the German name for coagulation or clotting of blood, and vitamin K consists of a group of fat-soluble vitamins, which have recently been receiving a lot of attention for their potential health benefits. Vitamin K2 is arguably the most important food supplement available for overall health with as many as 90 percent of people are at risk for a deficiency.
What do I need to know about vitamin K?
The vitamin K family is divided into a vitamin K1 and a group of vitamin K2 molecules including one called MK-4 and one called MK-7. Some of the early evidence suggesting the beneficial qualities of vitamin K2 came from Japan. In Eastern Japan consumption of natto—a naturally fermented soy product replete with K2—is common and rates of osteoporosis, diabetes, senile dementia, and heart disease are reported to be lower in eastern Japan compared to the rest of the country and far lower than in the United States and Europe.
What does vitamin K do?
Vitamin K1 has always been known as the "coagulation" vitamin because it helps keep the body’s blood-clotting mechanism functioning in a healthy manner. Vitamin K2, on the other hand, has been shown to activate 17 proteins. For example, vitamin K2 activates a protein called osteocalcin, which ensures that as much bone is built to replace the bone that is broken down. Vitamin K2 also encourages a protein called Matrix gla protein (MGP) to keep arteries healthy by discouraging calcium from sticking to the walls. The role of vitamin K2 has been studied in several medical conditions, including:
A recent study, published in the peer-reviewed journal Osteoporosis International, performed a meta-analysis involving over 6,000 subjects. The researchers found that the use of K2 in those diagnosed with osteoporosis played a role in the maintenance and improvement of bone mineral density.
2. Cardiovascular health.
In the Rotterdam Study, 4,800 subjects reported their dietary intake of K2/MK-7 and were followed over 10 years. The higher the dietary K2/MK-7 intake, the lower the rates of heart and all deaths observed. Calcification of the aorta, the major blood vessel in the body, was lower in those with higher intake of MK-7. Overall, the Rotterdam Study supports the notion that vitamin K2 may be critical for healthy aging particularly to avoid calcification and aging of critical arteries in the body.
In a study in Japan, administering vitamin K2 for four weeks led to improvements in insulin sensitivity, favoring freedom from diabetes. In a more recent publication that was a meta-analysis of the use of K1 or K2 in insulin sensitivity, the finding could not be reproduced. A recent review on vitamin K concluded that administering vitamin K2 to patients with the spectrum of diabetes disorders was promising.
Much research is taking place presently looking at the vitamin K family and its potential anticancer effect. Vitamin K2 may suppress growth and invasion of human liver cancer, pancreatic, and lung cancer cells. A study of over 11,000 patients showed that higher vitamin K2 intake was associated with a reduction in advanced prostate cancer.
I routinely recommend vitamin K2/M7 in my heart clinic to help maintain healthy bones and arteries. I am careful to avoid synthetic vitamin K2 and prefer when it is derived from sources like natto. Eating foods rich in K2, such as natto, which can be found in a sushi roll, is an option, but the taste is often described as unpleasant.