Healthy Decisions for the Love of Health

Role of Vitamin K in Preventing Calcification of Blood Vessels
by The Life Extension Foundation

Vitamin K helps prevent vascular calcification, improves bone quality

Richard Wood, Ph.D., is a researcher from Tufts University in Boston, where he directs the Mineral Bioavailability Laboratory at the USDA Human Nutrition Center on Aging. Dr. Wood presented an overview of the data concerning the newly discovered importance of vitamin K in regulating calcium metabolism and preventing both bone fractures and vascular and other soft-tissue calcification.

Until recently, vitamin K has been seen strictly as a pro-clotting factor, Wood pointed out. It regulates prothrombin, Factors VII, IX and X. But it is the newly discovered importance of vitamin K in regulating calcium deposition that makes it one of the key players in anti-aging protocols, especially in view of the fact that we tend to become increasingly deficient in vitamin K as we age. Postmenopausal women show lower levels of carboxylated ostecalcin compared to premenopausal levels, indicating a vitamin K deficiency.

Poor vitamin K status has been found to raise the risk of a heart attack 2.4 times-as much as smoking, Wood pointed out. The most likely reason is that vitamin K helps prevent vascular calcification. Wood explained that vitamin K is a limiting factor in the carboxylation of various bone-regulating proteins that help prevent bone formation in the wrong places, including the middle layer of the arterial wall.

Vitamin K was discovered to be a cofactor in the chemical reaction that adds the carboxyl group (COOH) to glutamate, making it possible for bone-regulating proteins such as osteocalcin to bind calcium. Osteocalcin is produced in the osteoblasts, cells that create new bone. It should be noted, however, that osteocalcin and related proteins have been found not only in bone, but also in soft tissue the brain, pancreas, and lungs. The speaker mentioned that one of the important vitamin K-dependent proteins is the matrix Gla protein, a potent inhibitor of soft-tissue calcification when it is sufficiently carboxylated.

In Japan, vitamin K has been approved for the treatment of osteoporosis, in combination with vitamin D3. Several epidemiological studies have found a significant increase in the risk of fractures associated with vitamin K deficiency. In particular, Wood cited the Framigham Heart Study. Those in the highest quantity of vitamin K intake showed a 65% reduction in hip fractures compared with those in the lowest quantity. In other words, those consuming the most vitamin K had only about a third of the hip fractures of those consuming the least vitamin K.

Wood emphasized, however, that studies have not found any effect of dietary intake of vitamin K on mineral bone density. A study of bone markers in Japanese children has strongly suggested that vitamin K, which increases levels of carboxylated osteocalcin, affects primarily bone quality, which translates into resistance to fracture, rather than mineral density.

Vitamin K intake was also found to be inversely correlated with aortic calcification, an important predictor of heart attack risk. Patients whose aortic calcification was evident in X-ray images had more undercarboxylated osteocalcin, indicating poor vitamin K status. Poor vitamin K status has been found to triple the risk of severe vascular calcification, Wood stated. Deficiency of vitamin K leads to undercarboxylation, and hence inactivity of bone-regulating proteins such as matrix Gla protein, resulting in soft-tissue calcification. And the greater the degree of calcification, the greater the risk of a heart attack.

Warfarin (Coumadin), an anticoagulant, depletes vitamin K and causes severe vascular calcification in rats. Bisphosphonate drugs can prevent this harmful side effect. Coumadin patients cannot take vitamin K supplements and are even told to avoid foods rich in vitamin K.

Though the speaker did not go into the neuroprotective role of vitamin K, it is worth noting that some researchers think that supplementing with vitamin K may help prevent Alzheimer's disease and ward off stroke. This is due to the ability of vitamin K to reduce neuronal damage by protecting the vascular system, guarding against inflammation and blocking excess infiltration of calcium into brain cells. Vitamin K is also involved in regulating important brain enzymes and growth factors. It seems that we are discovering more and more functions of this remarkable anti-aging vitamin.

Vitamin K from supplements is more bioavailable than dietary vitamin K, Wood pointed out. Since vitamin K is fat-soluble, it's a good idea to add olive oil (itself a source of vitamin K) or another healthy fat when you eat dark green vegetables such as spinach, broccoli, kale, green cabbage, brussels sprouts or lettuce (even pale lettuce such as iceberg supplies some vitamin K). Green plants supply the form of vitamin K called phylloquinone, or vitamin K-1. Our intestinal bacteria convert K1 to K2, or menaquinone (actually there are several menaquinones), the active hormonal form. Some menaquinone is also found in fermented products such as cheese or natto, a fermented soybean product, and in liver, meat and egg yolk.

As has been jocularly observed, as we age, we turn to stone. We calcify. More accurately, our arteries and organs calcify, while our bones decalcify. Vitamin K is an essential resource against this pathology of aging.

The role of dysregulated calcium metabolism in aging-related degenerative disorders, as well as the corrective role of magnesium, vitamin D and vitamin K, is finally beginning to get much-deserved attention. Supplementation with calcium alone is obviously not enough; some think it might even be harmful. It is critical to help the aging body control calcium. Vitamin K is the latest addition to our arsenal.

Le Magazine, February 2003 - Report Acam Convention 2002


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