Vitamin K2 is the most critical nutrient when it comes to preventing osteoporosis but it needs help from two other fat soluble vitamins: A and D. Without Vitamin K2 we cannot build bone. Unfortunately Vitamin K2 has decreased massively in our food supply and deficiency is widespread. A British study from 2005 found Vitamin K2 intake in children had dropped from 39mcg daily in the 1950s to 24mcg daily in the 1990s. Another problem is few doctors understand the central role of Vitamin K2 in preventing osteoporosis.
Vitamins A and D produce the specialist bone-building protein osteocalcin but this will only function if it is activated by Vitamin K2. Those low in Vitamin K2 in one study had a 65% higher risk of hip fractures.
Just as important Vitamin K2 activates another protein, matrix gla protein (MGP) which removes calcium from soft tissues and arteries. Without activated osteocalcin calcium cannot get into our bones and teeth and gets diverted to our arteries and soft tissue, increasing the risk of heart disease. Without MGP we can’t get calcium out of our arteries (mice with an inability to make MGP die rapidly from massive artery calcification). So Vitamin K2 has a role in preventing both osteoporosis and heart disease (a Norwegian study in 2004 found women with low bone density had more calcified plaques in their arteries).
This is why calcium and Vitamin D supplements have not been shown to help restore bone density. They can’t do this without Vitamin K2. Vitamin D has been shown to reduce fractures within the first year of taking it. This happens before bone density has changed and is probably due to its beneficial effect on muscle strength.
Osteoblasts are cells that build bones and teeth. Together with Vitamins A and D they secrete osteocalcin. However osteocalcin only works after it has been activated by Vitamin K2 (or strictly speaking carboxylated by it). Only then will calcium be drawn into bone and teeth. Without it calcium can end up in arteries instead which explains the known link between calcium supplementation and heart disease. In fact those with the highest intake of Vitamin K2 have 50% less heart disease (the Rotterdam study, 2004).
Breaking down bone
Old bone needs to be broken down and replaced by new bone otherwise you end up with brittle bones. To demonstrate how necessary this is, the whole skeleton is replaced every 7 to 10 years. Osteoclasts are cells that break down bone. However this needs to be done in a controlled fashion and Vitamin K2 reduces the number and activity of osteoclasts. In contrast, Vitamins A and D increase the number and activity of osteoclasts. This might seem like a bad idea but these vitamins all work together removing weakened bone where necessary in a balanced way to make way for stronger bone. We need all three of these vitamins to break down bone in the right way.
Other Benefits of Vitamin K2
In a study from the Netherlands those with the highest intake of Vitamin K2 lived 7 years longer. In animals K2 deficiency leads to type 2 diabetes and Vitamin K2 is known to increase insulin sensitivity.
What Your Doctor May Give You
Most doctors give a combination of calcium and Vitamin D and, if the osteoporosis is marked, they give drugs called biphophonates such as alendronic acid.
As mentioned giving calcium is a mixed blessing as it may end up in the wrong place if Vitamin K2 is deficient and increase the risk of heart disease. The EPIC study found those taking a calcium supplement had an 85% higher risk of heart attacks.
Vitamin D does reduce the fracture risk and will, with Vitamin A, produce osteocalcin. But unless this is activated by Vitamin K2 it cannot complete the job of building bone.
Biphosphonates stop bone breaking down. This is done by suppressing osteoclasts but, unlike Vitamin K2, they do nothing to build bone. Also the bone is broken down in an unbalanced way (unlike what happens when Vitamin K2, Vitamin D and Vitamin A work as partners). This can cause brittle bones and, in time, increase the risk of atypical fractures (fractures which occur without trauma). They also increase the risk of oesophageal cancer and osteonecrosis of the jaw, a progressive, frightening and untreatable condition.
For any drug it is important to look at the benefits and weigh it against the risks. Biphosphonates have slight benefits which come with big risks. Compare this with Vitamin K2 which has greater benefits and no known risks.
Which Foods contain Vitamin K2?
Vitamin K2 comes from purely animal sources. Most farm animal (and herbivores) can convert Vitamin K1 (which is found in plants) and convert it to K2. (Vitamin K1 plays no part in bone health). We have virtually no capacity to do this conversion so we need to get K2 from animal sources. In the past most Vitamin K2 came from foods like milk, butter, cheese and eggs. Unfortunately, due to modern farming methods, most animals are now fed on grains rather than grass and plants and even a small amount of grain in their diet greatly depletes Vitamin K2. Liver is still a good source as is egg yolk, wild game and hard cheeses. However it is easy for Vitamin K2 to be virtually absent in the modern diet and depletion can occur within 7 days if it absent.
There are two types of Vitamin K2: MK-4 (menaquinone-4) supplements which are short-acting (needs to be taken three times daily) and MK-7 supplements which are longer-acting and can be taken daily. MK-7 supplements have obvious advantages. Take 90-120 mcg daily of MK-7 for routine use and double this if you have osteoporosis, menopausal or post-menopausal bone loss or heart disease (or 45mg daily of the MK-4). Remember Vitamin K2 works in tandem with Vitamin D and A so supplement these as well (I would suggest 2000 to 4000 IU of Vitamin D daily and 5000 IU of Vitamin A daily). In one study of 16,057 women, initially without cardiovascular disease, followed for 8 years, the risk of cardiovascular disease decreased by 9% for each10mcg of MK-7 taken.
Vitamin K2 and anticoagulants
Vitamin K2 interferes with warfarin, even at low dosages. In fact warfarin depletes Vitamin K2 and leads to arterial calcification. It is still possible to use the two together (and reduce arterial calcification) but this needs to be done with care using blood test to monitor the INR.
Other anticoagulants such as DOACs (direct acting anticoagulants), aspirin and clopidogrel are not thought to interact with Vitamin K2.
Other Help for Osteoporosis
Although the fat soluble vitamins, A,D and K2 are the mainstays for healthy bone, other minerals are important, notable magnesium. Magnesium is also needed to activate Vitamin D.
Weight-bearing exercise is also very important for strong bones.
Bone Density Scans
Dexa scans are used to measure bone density and gives a T score. However remember bone density is not the only factor in fractures. The T score should be between 0 and -1. Osteoporosis is defined as -2.5 or less and osteopenia as -1 to -2.5.
Typically the DEXA scan is repeated after a few years. As bone density changes very slowly: usually by only 1% in a year and the variation between two readings of a DEXA scan can be as much as 6% there is little point in repeating it after a year or two.