Most people are familiar with the importance of Vitamin D. Unfortunately, it is not common knowledge (yet) that supplementing with, or getting an adequate amount of Vitamin K2 in the diet is just as important. The fat-soluble Vitamins D, K2 and A all work together synergistically. When we get too much of one, such as Vitamin D, and not enough of the others, Vitamin K2 and A, it can pose some problems (1, 1.5).
WHAT HAPPENS WHEN WE TAKE TOO MUCH VITAMIN D AND NOT ENOUGH VITAMIN K2?
Vitamin D helps your body to absorb calcium. Once calcium is absorbed, Vitamin D has no control over where it ends up in your body. This is where Vitamin K2 comes in.
Vitamin K2 activates, or “turns on” a number of different proteins in the body. Some of these K2 activated proteins guide calcium into our bones and teeth, where calcium belongs. When these calcium guiding proteins don’t their job, it is because there is no Vitamin K2 to turn them on.
This is really important for two reasons; osteoporosis and cardiovascular disease. Vitamin D enhances the absorption of calcium into the body (source). But, when there is no K2 to activate the proteins that send calcium to the bones, the calcium settles in our soft tissues. This is associated with vascular calcification and kidney stones. In fact, Vitamin K2 is proving to be very beneficial in the prevention and treatment of osteoporosis, cardiovascular disease, and kidney stones (2, 3, 4, 5, 6, 7, 8, 9, 10, 11).
To explain an incredibly complex process simply, Vitamin D and Vitamin K2 work together as a team. Vitamin D helps get calcium in the body, K2 “sends” it to the bones. Both nutrients are essential and beneficial to bone health and cardiovascular health.
WHY VITAMIN K2 IS A BETTER NUTRIENT TO STRENGTHEN BONES THAN CALCIUM
A new study has found that supplementing with calcium is not as good for us as we previously believed. Not only does supplementing with calcium have no effect on bone density, but it will increase our chance of developing atherosclerosis, heart disease, and kidney stones (11). If strengthening our bones is what we are aiming for, supplementing with K2 is a much better idea (12).
In fact, the Japanese diet is very low in calcium, but they also have a very low rate of osteoporosis. This is opposite of Americans, who have a high calcium intake but also a much higher rate of osteoporosis (13). The Japanese diet includes natto, which is a slimy, stringy fermented soybean. Natto the richest food source of Vitamin K2, and is the reason Japanese women have low rates of bone fracture (14).
THE DIFFERENCE BETWEEN K1 AND K2
Vitamin K1 (phylloquinone) was discovered in the late 1920s. It was named Vitamin K after the German term koagulation, because of its critical function in blood clotting. Vitamin K1 is recycled in the body and is abundant in green leafy vegetables. It is nearly impossible to be deficient in Vitamin K1.
Vitamin K2 (menaquinone), on the other hand, has just recently begun to attract the attention it deserves. Vitamin K2 is not recycled in the body and is more difficult to obtain from the diet. In fact, much of the population is actually deficient in Vitamin K2 (15).
Humans do have the ability to convert K1 into K2, but the rate of conversion is inefficient at best. Contrary to popular belief, this small rate of conversion does not supply our need for K2. The Rotterdam Study discovered that “Intake of menaquinone (K2) was inversely related to all-cause mortality and severe aortic calcification. Phylloquinone (K1) intake was not related to any of these outcomes.” The results from this study were so shocking, the study was repeated by a different set of researchers. The Prospect Study had the same results. They also found that for every 10 mcg increase of K2 in the diet, there was a 9% decrease in the chance of developing coronary heart disease.
If our bodies made enough K2 from our K1 intake, we would find the same benefits from K1 as K2. But this is not the case.
OTHER BENEFITS OF VITAMIN K2
K2 not only activates calcium-directing proteins but also activates many other health-promoting proteins as well.
- Vitamin K2 plays a strong role in the prevention of many types of cancer, including prostate, colon, liver, and lung. K2 prevents cells from behaving badly, by inhibiting cells from growing wildly out of control, and not dying when they should. Those with an increased risk of cancer may want to consider increasing their Vitamin K2 intake (16, 17, 18, 19, 20, 21, 22).
- K2 improves insulin sensitivity, which is important for those who have diabetes or are at risk for diabetes (23).
- Vitamin K2 can prevent varicose veins. Which makes sense, when you think about K2’s role in preventing calcium from calcifying in the veins.
- Vitamin K2 can improve dental health (24).
- Vitamin K2 deficiency decreases testosterone production, whereas a higher K2 intake enhances testosterone production in the testes (25, 26).
- Vitamin K may play a role in brain health and the prevention of Alzheimer’s disease (27, 28).
- Excessively wrinkly skin is associated with low bone density in postmenopausal women (29). We just learned that a low intake of Vitamin K2 is associated with low bone density. So, Vitamin K2 deficiency may also be associated with wrinkly skin. Improving your K2 intake may keep you looking younger. Maybe K2-rich Natto is the reason Japanese age so gracefully.
FOODS RICH IN VITAMIN K2
Vitamin K2 is found in fermented foods and animal products. Grass-fed animal products are much higher in Vitamin K2 compared to grain-fed animal products. Unlike humans, ruminant animals are excellent at converting K1 to K2. Ruminants that are fed their natural food source, grass, have a much higher intake of K1 than grain-fed animals, which results in their products being a much richer source of K2.
Here is a list of foods highest in Vitamin K2: (30)
- Natto – 1,100 mcg per serving
- Goose Liver – 369 mcg per serving
- Hard Cheese – 76 mcg per serving (grass-fed is better)
- Soft Cheese – 56 mcg per serving (again, grass-fed is better)
- Free Range Egg Yolk – 32 mcg per egg
- Conventional Egg Yolk – 15 mcg per egg
- Butter from a Grass-Fed Cow – 15 mcg per serving
- Chicken Breast or Leg – 9 mcg per serving
- Sauerkraut – 4.8 mcg per serving
HOW MUCH VITAMIN K2 SHOULD WE SUPPLEMENT WITH?
Seeing as Vitamin D, K2 and A all work together synergistically, it is logical to ensure that you get a balanced intake of all three. Unfortunately, these vitamins have primarily been studied in isolation so no one knows the exact ratio we should aim for.
Dr. Kate Rhéaume-Bleue, who literally wrote The Book on Vitamin K2 recommends taking “equal amounts of A and D, with 100 mcg K2 (as MK-7), or 1,000 mcg (as MK-4) per 1,000 IU A/D.” She also states that “the most recent clinical trials use 180 mcg per day for bone health, and 360 mcg daily for arterial calcifications” (31). Dr. Kate also suggests supplementing children with 120 mcg per day, which is near an adult dose. They do have small bodies, but their small bodies are quickly growing.
Vitamin K2 is a very safe nutrient. There has been no toxicity level established and is safe even at high doses (32).
There are two forms of Vitamin K2 you will find in supplements: MK-4 and MK-7. Supplemental MK-4 is made synthetically and has a shorter half-life than MK-7. Supplemental MK-7 is made from natto and has a longer half-life than MK-4. Generally, the dose of MK-4 is about 10 times higher than MK-7.
Many vitamin companies are starting to catch on to the importance of Vitamins K2 and D together, and are formulating supplements that contain both vitamins. This makes it easier to take, as you just have to take one supplement, rather than two to get both.
You can also make soy-free, K2 rich natto at home using natto spores, and black beans.
WHO SHOULDN’T SUPPLEMENT WITH VITAMIN K2?
A group of people who shouldn’t supplement with K2 is those taking warfarin (Coumadin), as this drug prevents clotting by creating a Vitamin K deficiency in the blood. Other blood thinners such as clopidogrel (Plavix), dabigatran (Pradaxa), prasugrel (Effient), rivaroxaban (Xarelto), aspirin or fish oil thin blood through other mechanisms not related to Vitamin K, so K2 does not have an effect on their function (33).
**But as always, talk to your medical care provider before supplementing!**
I WOULD LIKE TO HEAR FROM YOU!
Have you heard of Vitamin K2? Did you know how important it is to our cardiovascular and bone health?
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