Unlike most people imagine, vitamins are not a single molecule and are quite often a name for chemically and functionally related substances. It means that there are many sub-types of certain vitamins like vitamin K. These subtypes may have slightly different properties and health benefits. Thus, it is essential to take its most effective subtype when taking any vitamin.
Vitamin K is a fat-soluble vitamin. It is further divided into two categories: phylloquinone (vitamin K1) and a series of menaquinones (vitamin K2). There are nine known subtypes of vitamin K2 named from MK-4 to MK-19. However, among them, MK-4 and MK-9 are the most thoroughly studied by science and known to have multiple health benefits.
Vitamin K is essential for blood clotting. However, in recent years, researchers have found that it has many other roles in the body. For example, it appears that vitamin K is also good for bone health, prevents atherosclerosis, lowers inflammation, and may even prevent certain types of cancers. Interestingly, it appears that vitamin K2 has a greater number of health benefits. Thus, nutritionists have started recommending vitamin K2 and not just vitamin K in recent years.
Vitamin K1 is mainly found in green leafy vegetables and many other foods. Most of the dietary intake of humans is of vitamin K1. It is in abundance in collard, broccoli, carrot juice, pumpkin, soybeans, etc.
Vitamin K, including K1, plays a vital role in blood clotting. Vitamin K1 is especially good for maintaining blood clotting and vascular health. However, studies show that it is relatively less active than other vitamin K subtypes in lowering inflammation or improving bone health, as most of it is present in the liver.
Subtypes of vitamin K2
Vitamin K2 seems quite different than vitamin K1, as it has greater extra-hepatic activity. It means that K2 is better for lowering inflammation, boosting bone health, improving heart health, and so on. In addition, it may be better for preventing atherosclerosis.
Vitamin K2 is primarily present in fermented foods. Thus, it is found in natto, sauerkraut, dairy products, etc. It is also present in small amounts in animal meat and poultry products. Additionally, it is worth understanding that the human body can also produce vitamin K2 a bit with the help of gut microbiota.
Studies show that about 50% of the vitamin K requirement is of K1 and another fifty percent of K2. Since K1 is relatively abundant in commonly consumed food items, one is more prone to a vitamin K2 deficiency. Moreover, a higher prevalence of dysbiosis is only making things worse.
Menaquinone 4 (MK4) is quite good for bone health, reducing inflammation, boosting vascular health, and more. Therefore, it is relatively more important than vitamin K1 for other body functions apart from maintaining blood clotting function.
However, MK4 deficiency is rare. It is because the human body can readily produce it through the conversion of vitamin K1. Another reason why one would not supplement this vitamin is due to its poor bioavailability. Studies show that MK4 is barely bioavailable, and not more than 10% or even less of it is absorbed from foods.
Though it is quite good for bone and vascular health, but its deficiency is rare. It is only needed by the body in minute amounts.
Menaquinone 7 or MK7 is perhaps the most active form of vitamin K2. It cannot be produced by the body. It is quite suitable for other health benefits apart from blood clotting. Thus, it appears to be one of the best subtypes of vitamin K for bone and vascular health. Some researchers are even proposing to consider it a separate vitamin.
Additionally, studies show that it is also one of the most bioavailable forms of vitamin K. It seems that about half of all the MK7 is absorbed. Thus, it is good to use this form as a supplement.
In recent years researchers have started focusing more on this subtype of vitamin K, as they noticed that supplementing vitamin K1 is not enough to prevent specific vascular issues or strengthen bones. Studies show that MK4 is quite good for preventing bone loss. It also increases vascular elasticity through increased NO production.
The combination of K2 and D3
A vitamin is good, but two are better. In the body, multiple vitamins work in synergy with each other. It seems that there is a particular synergy between K2 and D3.
Vitamin D3, or the sunshine vitamin, promotes calcium absorption from foods. On the other hand, vitamin K2 activates certain enzymes that remove calcium from soft tissues and also activate osteocalcin. Thus, vitamin D3 increases calcium availability, and vitamin K2 improves its utilization by the bones.
Additionally, K2 also boosts endothelial NO production and helps reduce the accumulation of calcium in blood vessels. Thus, it may improve vascular elasticity and prevent plaque formation.
There are many studies to confirm the benefits of combining these two vitamins. For example, in one of the studies for up to 24 months, combined use of these vitamins was much better in increasing vertebral bone mass and reducing the risk of osteoporosis in post-menopausal women. Similarly, it also helps reduce the risk of plaque formation in arteries and thus reduces the risk of cardiovascular diseases.
Most people these days consume sufficient calories, and they also try to include fresh veggies in their diet. Yet, it appears that vitamin K deficiency is quite common. Additionally, it appears that vitamin K from vegetables does not appear to help. It seems that researchers have now understood the reason. Vitamin K2, especially the MK7 subtype, is a highly bioavailable form of vitamin K and is particularly good for bone and vascular health. Additionally, combining it with vitamin D3 may have additional benefits for bone and vascular health.