Osteoporosis is a loss of bone mineral density and thinning of bone tissue that causes bones to become more porous and prone to fracture. It is the most common bone disease, with one in five women over the age of 50 having the diagnosis, and many more having the disease and yet to be diagnosed. Half of women over the age of 50 will experience a fracture due to diminished bone density. There are no symptoms in the early stages of the disease and often the first sign of osteoporosis is a bone fracture due to little or no trauma.
Conventional wisdom has suggested that since osteoporosis is characterized by a lack of calcium in bones, increasing calcium intake should be the most important remedy for the problem. However, despite a drastic increase in women supplementing with calcium and consuming calcium-rich foods, there is only modest improvement in their risk of osteoporosis in menopause. Some studies have even shown an increase in risk of cardiovascular disease in women who supplement with calcium.
Happily, we now have other research that has identified a nutrient that can safely guide calcium into bones and teeth, strengthening mineral density where we need it, while keeping the mineral out of arteries, and even clear away pre-existing arterial calcium deposits. This is the action of vitamin K2, a long misunderstood fat-soluble vitamin that works with vitamin D to put calcium in its place.
Although we think of our bones as solid and unchanging, the skeleton is as dynamic as any other body tissue. Bone tissue is constantly being modified and maintained by a process called “remodeling”, which happens because of the actions of cells known as osteoblasts and osteoclasts. Osteoblasts are the bone-building cells. They originate in bone marrow and play a role in mineralization of the bone matrix, the structural storage area that holds calcium within bone. Osteoclasts, on the other hand, are cells that help tear down bone in a breakdown process known as bone resorption. Together with osteoblasts, these cells eliminate areas of weakness and repair cracks and fractures to keep bones healthy and strong. Maintaining a healthy balance between the action of osteoclasts and osteoblasts is essential to preventing osteoporosis.
Vitamin K2’s main role in bone health is to carboxylate (activate) certain proteins, allowing them to bind calcium. There are several vitamin K2-dependent proteins in bone, but osteocalcin is the most abundant and best known. It is the main bone protein required for calcium deposition into bones and teeth. Only once it is activated by Vitamin K2, can osteocalcin grab on to calcium and lay it into the bone matrix. Without sufficient Vitamin K2 to activate it, osteocalcin has no effect and calcium will not be deposited into the bone and osteoporosis sets in. We have learned a lot about the bone-building benefits of Vitamin D over the last few years… but now we know that this action is actually dependent on Vitamin K2. Vitamin D, assisted by vitamin A, stimulates the production of osteocalcin, and Vitamin K2 activates it. This is a perfect example of how many of our nutrients work together to achieve optimal health.
Vitamin K2 is not only a benefit to bones by activating osteocalcin, but it also helps to prevent (and reverse) osteoporosis in other ways as well. Research shows that K2 partners with vitamin D3 to inhibit the production of osteoclast cells that break down bone. K2 targets osteoclasts to undergo apoptosis (programmed cell death), leading to a reduction in the number of osteoclast cells. Impeding the action of osteoclasts in this way helps the bone-building osteoblasts catch up to maintain that healthy balance.
We haven’t always been deficient in Vitamin K2 ~ it was once abundant in our diets. When farm animals grazed on pasture, foods like eggs and butter were brimming with vitamin K2. As factory farming took over and animals were gradually removed from the pasture, vitamin K2 levels plummeted and deficiency crept in. Until we are successful in our movement back towards traditional farming practices, here are some suggestions about foods rich in Vitamin K2 to put back on your plate and get K2 back into your body (per 3 1/2 ounce portion):
- Natto (1103mg)
- Goose liver pâté (369mg)
- Hard cheese (Dutch Gouda style) (76.3mg)
- Soft cheese (French Brie style) (56.5mg)
- Egg yolk (15.5mg)
- Butter (15.0mg)
- Chicken liver (12.6mg)
- Chicken breast (8.9mg)
- Ground beef (from grass-fed cows) (8.1mg)
- Whole milk (1.0mg)
Since the best source of K2 is from natto – a Japanese fermented soy product that is difficult for most people from North America to acquire a taste for, most of us will need to consider supplementation to get ideal intake. However, we aren’t certain yet exactly what that dosage should be. Since the official recommended daily intake (RDI) for vitamin K doesn’t distinguish between the two main forms of vitamin K, and is based on the body’s requirement for K1, not K2, we can disregard this as a guideline. Until a new RDI is established, most sources are suggesting that a supplement of Vitamin K2 (from K2-7) provide between 120-360mcg per day.
As this vitamin is about to receive celebrity status in health journals in the near future, we look forward to hearing more about the benefits of K2, learning about how to test for deficiency and how to dose for best absorption and health. Although we will be looking for it to become more available as part of multi-vitamin and bone-building formulas, for now I recommend taking it alone or in combination with vitamin D on a daily basis.
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