While vitamin K is best known for its role in blood clotting, this nutrient also
plays an important part in the maintenance of healthy bones. Noted nutrition authority
Dr. Alan Gaby has suggested that vitamin K is as important to bone as
calcium. So let’s follow Dr. Gaby’s lead and delve a little
deeper into its role in bone health.
Vitamin K is required for the synthesis of osteocalcin, the bone protein
matrix upon which calcium crystallizes. Osteocalcin provides the structure and order
to bone tissue; without it bone would be fragile and easily broken. Vitamin K also
aids in the binding of calcium to the bone matrix — in essence, it serves
as the “glue” that binds calcium onto the skeleton.
Just as vitamin K is central to bone formation, it also appears to play
an important role in fracture healing. Vitamin K levels fall during recovery
from fracture, and it appears that this nutrient is actually drawn from the rest
of the body to the site of fracture.
Vitamin K is not a single nutrient, but the name given to a group of vitamins of
similar composition. The two main groups that occur naturally are phylloquinone,
or K1, which is found in plant-based foods, particularly green leafy vegetables;
and the menaquinones, or K2, which are produced by bacteria in fermented
foods and to some minor extent in our intestinal tracts. In combination with
vitamin D and calcium, both vitamins K1 and K2 increase bone quality. But
vitamin K2 is more bioavailable, longer lasting, and provides for greater increase
in bone strength.
The more we learn about this vitamin, the more we see it takes various forms and
roles in the body. To date most of the research has been done on K1. But a new wave
of research is now focusing on K2 — in particular the subset of K2 known as
menaquinone–7, or MK–7. This research documents the superior ability
of MK-7 over K1 to enhance both bone and heart health. Getting enough of the K2
forms of this vitamin has been found to be especially important for healthy bones
in patients being treated with oral anticoagulants, such as warfarin (Coumadin).
Aside from getting K through dietary sources, vitamin K can also be produced in
the body by certain beneficial intestinal bacteria. By compromising this process,
long-term use of antibiotics can lead to vitamin K deficiency. Aside from oral antibiotic
and anticoagulant use, culprits in vitamin K inadequacy include the freezing of
foods, mineral oil laxatives, rancid and hydrogenated fats, radiation, impaired
fat absorption, sulfa drugs, and certain liver diseases.
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