Vitamin K Generates Interest for Role in Full-Body Health

Aug. 24, 2007
Vitamin K may the last in the vitamin alphabet, but this least-familiar and least-studied vitamin is generating second looks for its role in heart, vascular and bone health.

Vitamin K usually prompts the question, "What happened to vitamins F, G, H, I and J?" But K got its name from its critical role as a cofactor for blood coagulation proteins in the liver. Discovered by Danish scientist Henrik Dam, he named the vitamin by the Danish word for coagulation, which is spelled with a "k."

Vitamin K is found naturally in meat, eggs, cheese, fermented soy as menaquinone (called K2) and in dark leafy greens, such as broccoli, as phylloquinone (called K1). The vitamin is fat-soluble, and is stable enough to withstand heat in processing.

In spite of its wide availability, earlier studies showed intake to be low among seniors, and more recent research at Tufts University, Boston, indicated adults aged 18 to 44 are also at risk for low intake. The need for more adequate vitamin K intake has become more critical following recent studies that show the vitamin to play a more important role in human health than previously recognized.

In a comprehensive study of nearly 5,000 subjects over seven to 10 years, decreased intakes of menaquinone was shown to increase the calcium buildup on arterial walls that is part of the process of hardening of the arteries. The 2004 study, now known as the Rotterdam Study, concluded vitamin K2, could help reduce risk of heart attacks and cardiovascular disease secondary to arterial hardening by up to half.

Animal studies suggest vitamin K2 could even reverse the effects of arterial calcification. For example, research by Leon Schurgers, Ph.D. at Maastricht University, The Netherlands published in April in the American Society of Hematology, revealed that high intake of vitamin K reduced arterial calcification by 37 percent in the animals tested.

The calcium factor -- calcium's role in reduced cardiovascular disease risk -- generated a wealth of research leading to calcium expanding from its recognized role as key to bone health to that of heart health. That link positions vitamin K as a potential key functional ingredient for foods and beverages.

The mechanism with which vitamin K2 helps decrease calcium deposition on arterial walls seems to be unique to the long-chain menaquinone form. The Rotterdam Study showed no such mechanism with vitamin K1.

"A calcium regulating protein called Matrix GLA Protein, or MGP, is necessary for the metabolism of calcium in the vascular tissues," explains Eric Anderson, manager of brand management. PLThomas (, Morristown, N.J. Related to its role as a regulator of the protein osteocalcin, which controls the deposit of calcium in bone, the vitamin also acts as a control mechanism for the regulation of calcium in related tissues, such as cartilage and vessel walls.

PLThomas recently began marketing a long-chain menaquinone product, MenaQ7, derived from natto (fermented soy). "K2 is the form of vitamin K that activates MGP, helping the body use and then recycle the excess calcium. Without enough vitamin K2, the body may accumulate too much calcium in the arterial wall," Anderson adds.

Vitamin K has yet to be snapped up by processors developing and manufacturing foods and beverages for wellness. Given the rapidly growing category of "be well-stay well" foods and beverages for the aging baby boomers (see "Fountain of Youth" in Food Processing.), however, K could readily be positioned as a major player on the nutraceutical stage.