Doctors Best Natural Vitamin K2 featuring MenaQ7 contains pure MenaQ7, the superior form of vitamin K for optimum bioavailability and delivery to the body. MenaQ7 is purified from natto, a traditional Japanese breakfast food made of fermented soybeans that is naturally rich in Vitamin K2. Not just a single vitamin, Vitamin K is a family of fat-soluble vitamins with similar structures, but different metabolic properties. Vitamin K2 belongs to the group of vitamin K compounds called “menaquinones” which demonstrate greater bioactivity when compared to vitamin K1 (the ordinary form of supplemental vitamin K). Vitamin K2 is absorbed more completely, remains in the body longer and delivers more benefits for bones, blood vessels and other soft tissues.

Features & Benefits:

• Science-based nutrition
• Dietary supplement
• Supports bone health and soft tissue elasticity
• Delivers optimum levels of vitamin K to bone and soft tissue
• Supports calcium metabolism for maintenance of healthy bone

The Importance of Vitamin K
Vitamin K, a fat-soluble vitamin, is primarily known for its role in regulating blood coagulation. Vitamin K is required for the activity of specialized proteins that control blood clotting (Coagulation factors II, VII, IX) in a series of metabolic steps known as the coagulation cascade. The daily intake of vitamin K recommended by the National Academy of Sciences is based on the amount needed for biosynthesis of these clotting factors in the liver.

Vitamin K-dependent proteins are also found in bone and soft tissues, including osteocalcin, the protein that deposits calcium in bone. Activation of vitamin K-dependent proteins occurs through carboxylation, a metabolic process that adds a molecule composed of carbon, hydrogen and oxygen to glutamate, an amino acid within the protein structure. (Vitamin-K dependent proteins are also referred to as “Gla proteins.”) Osteocalcin cannot perform its function of incorporating calcium into bone unless it is activated first. A rise in the amount of inactive (under–carboxylated) osteocalcin circulating in the blood is now regarded as a measure of vitamin K deficiency. Vitamin K supplementation has been shown to decrease blood levels of inactive osteocalcin.

Studies report finding elevated levels of inactive osteocalcin in post-menopausal and elderly women. Other studies bring to light a connection between inactive osteocalcin and the deterioration of bone quality and strength that occurs with aging. In view of this, it is probably not coincidental that elderly women suffering from fracture of the hip have been found deficient in vitamin K, when compared to other women in the same age groups.

The importance of vitamin K for bone health was underscored by the findings of a 10-year dietary analysis of 72,327 women. When the data was checked for an association between vitamin K status and hip fracture, it was shown that the risk of hip fracture and vitamin K were directly related. Women with the lowest dietary intake of K had the highest risk.

While osteocalcin is essential for keeping calcium in bone, Matrix Gla Protein (MGP), another vitamin-K dependent protein, helps keep calcium from accumulating abnormally in soft tissues such as arteries. Arterial calcification, commonly known as “hardening of the arteries,” is a major contributing factor in the impairment of circulatory health that occurs with aging. Indeed, the calcium content of coronary arteries may be a predictor of mortality risk and an indicator of biological age.

As with osteocalcin, MGP must be carboxylated to be activated. Inactive MGP tends to collect in calcified arteries. A recent study found a strong connection between blood levels of inactive MGP and arterial calcification. Previous research discovered a link between hardening of the arteries and poor vitamin K nutrition.

Forms of Vitamin K
Vitamin K exists in two major forms: phylloquinone and the menaquinones. Phylloquinone, designated as vitamin K1, is the major dietary form in food and supplements. Menaquinones, designated as vitamin K2, are synthesized in the large intestine by gut bacteria, although how much this contributes to the body’s vitamin K supply is somewhat uncertain. Menaquinones are named MK-7, MK-8 and MK9, according to the length of structurally related molecular side chains attached to the parent molecule. Fermented foods contain substantial amounts of K2, produced by bacteria that cause the fermentation. MK-7 is the primary menaquinone found in fermented foods such as natto. Two menaquinones are available in dietary supplements; MK-4, a synthetic vitamin K2, and MK-7, which is natural. MK-7, thanks to its longer side chain, is more stable in the bloodstream than vitamin K1. Recent research reveals that MK-7 contributes to optimum vitamin K storage in the body, and functions more effectively as a co-factor for the activation of osteocalcin that is so critical for bone strength, as discussed above. This characteristic of vitamin K2 is a major advantage, in view of evidence that very high intakes of vitamin K1, on the order of 1000 mcg daily (more than ten times the RDI), are needed to maintain optimum levels of activated osteocalcin. For older women in particular, consuming vitamin K1 at the current RDI may not be sufficient to achieve vitamin K’s bone health benefits.

Research on Vitamin K2
A large-scale study on vitamin K intakes among 5,000 Dutch persons suggests that vitamin K2 may help maintain healthy blood vessels, and perhaps even prolong life. The study participants were divided into four groups based on their daily vitamin K intake from food sources, as assessed from a food frequency questionnaire. Compared to those in the low vitamin K2/menaquinone group, subjects at the highest consumption level had substantially superior heart health. Similar associations were not seen for vitamin K1.

Natto consumption is markedly higher in eastern Japan compared to western Japan. Interestingly, bone outcomes are correspondingly better among eastern Japanese women, which prompted a study of vitamin K2, as MK-7, in the blood of natto consumers. Not surprisingly, natto eaters have higher levels of MK-7. The data further revealed a correlation between more natto in the diet and stronger bones. Another population-based study in Japan found a direct link in postmenopausal women between natto consumption and bone mineral density (BMD). BMD, the content of calcium and other minerals in a segment of bone, is a measure of bone strength and resistance. Over a 3-year period, women increased their hip BMD with more frequent natto intake.

In summary, emerging science clearly shows that the body’s need for vitamin K exceeds the amount necessary for its basic function of maintaining normal blood coagulation. Vitamin K is gaining recognition as an essential nutrient for bones and soft tissues. By activating the key Gla proteins such as osteocalcin and MGP, vitamin K helps maintain mineralization of bone while counteracting mineralization of tissues where calcium doesn’t belong. Compared to other forms of vitamin K2, the effective dose of MK-7 is substantially lower, making it a superior choice for long-term consumption as a dietary supplement.