Vitamin K is a fat-soluble vitamin, most well known for the important role it plays in blood clotting. However, vitamin K is also absolutely essential to building strong bones and preventing heart disease, and is a crucial part of other bodily processes. Vitamin D is a critical nutrient for optimal health and is best obtained from the conversion of cholesterol in skin through sun exposure or a safe tanning bed (one with mostly UVB rays and little to no UVA). However, many are taking oral vitamin D, which may become problematic unless you’re also getting sufficient amounts of vitamin K2. And if you’re taking the D2 form instead of D3, you are actually creating a deficiency of this vital nutrient since the body cannot convert D2 into a useable form and must instead pull from stores in the body to compensate.
While K1 plays a vital role in the liver to activate blood clotting, Vitamin K2 engages in a delicate dance with vitamin D, and you need both in adequate amounts for optimal health.
Vitamin K2’s most important role is in the prevention of cardiovascular disease; more specifically, coronary artery disease. Whereas vitamin D provides improved bone development by helping you absorb calcium, vitamin K2 directs the calcium to your skeleton, while at the same time preventing it from being deposited where you don’t want it, such as organs, joint spaces and arteries.
In the absence of other important cofactors, such as magnesium, vitamin D and vitamin K2, calcium CAN have adverse effects, such as building up in coronary arteries, initiating excessive clotting and causing heart attacks. A large part of arterial plaque consists of calcium deposits (atherosclerosis), hence the term “hardening of the arteries.” Moreover, atherosclerosis can progress for many years, even decades, without symptoms, because the opening of the artery (lumen) formed by the arterial lining is still elastic enough to stretch to accommodate a degree of accumulated plaque. That is, only if the artery has not begun to calcify, as the formation of a calcified fibrous cap on top of the arterial plaque deposit prevents further compensatory luminal expansion and therefore is the final, fatal step in the progression of the fatal disease.
We also know that vitamin K2 activates a protein hormone called osteocalcin, which is needed to bind calcium into the matrix of your bone. Osteocalcin also appears to help prevent calcium from depositing into your arteries.
In other words, without the help of vitamin K2, the calcium that your vitamin D so effectively lets in might be working AGAINST you — by building up in your coronary arteries rather than your bones. If you take calcium and vitamin D but are deficient in vitamin K2, you could be worse off than if you were not taking those supplements at all!
In addition to its role with osteocalcin, one of the mechanisms by which K2 exerts a protective role against vascular damage is its impact on Matrix GLA protein, or MGP. MGP is the protein responsible for protecting your blood vessels from calcification. When your body’s soft tissues are damaged, they respond with an inflammatory process that can result in the deposition of calcium into the damaged tissues, among other harmful effects. Over time, repeated inflammation and damage to the arteries results in the buildup of plaque and the onset of coronary artery disease, leading right down the path to a heart attack.
Vitamins D and K2 work together to increase the action of MGP, the only mechanism that guards against calcium crystal formation in arteries. However, even most “healthy” adults, if not taking proper supplementation, are insufficient in vitamin K to a level that approximately 30% of their MGP is synthesized in an inactive form. At this level, protection against cardiovascular calcification is only 70% at best in the young, healthy population, and this figure only decreases with increasing age.
There are several forms of vitamin K2, which are obtained from different sources. Two of these forms (MK-8 and MK-9) come primarily from raw and fermented dairy products, such as kefir, certain cheeses, and butter from grass-fed cows. The most significant form of K2 is MK-7 and can be found in highest concentration in the fermented soy product natto. Natto can provide the entire recommended daily dose of K2 in just one half ounce serving. MK-7 can be found in other fermented foods as well, including fermented vegetables made with a starter culture containing vitamin K2-producing bacteria, and non-fermented foods such as lamb, duck, beef liver, dark meat turkey and chicken liver. Bacteria lining the tract of the large intestine are also prolific producers of K2; just another example of why proper gut flora is so vital to robust health.
Bottom line: if you are going to supplement with calcium, you need to be sure its intake is properly balanced with that both vitamin D3 and vitamin K2.