When teaching people about the different important roles each vitamin plays in the body, there is a tendency to start counting down from Vitamin A, on to B and following the alphabet through to E. Logically, people who don’t know their vitamins assume the next vitamin to be F – but there is no such thing! Nor is there a Vitamin G, H, I or J. The reason is what lies behind the letter K.
Vitamin K comes from the German word koagulation, explaining vitamin K’s primary purpose: to help blood to coagulate (clot). Vitamin K is actually a group of compounds, the most common and important of which are vitamins K1 and vitamin K2 (less common is Vitamin K3). Together these play a key role in preventing excessive bleeding and ensuring your blood clots as it should; and also ensuring you have strong and healthy bones.
It’s rare people take Vitamin K as a dietary supplement as almost all diets contain a few all-important vitamin K containing vegetables, unless you’re avoiding all your greens! You’ll be surprised to learn just how much vitamin K1 naturally occurs in vegetables. Whilst vitamin K2 is usually obtained from meats, eggs and dairy products – if you’re a vegetarian, there are a few tricks in obtaining Vitamin K2 without the need for animal-based products. Read on to learn more!
This article explains what vitamin K is, explores the importance of it and how you can very easily ensure you’re consuming enough vitamin K to have healthy blood and bones.
Contents
Vitamin K’s role in coagulation
As mentioned above, vitamin K’s primary role in our bodies is in helping blood coagulate or ‘clot’. You might believe blood clots are bad, imagining deep vein thrombosis and other diseases, but it’s important for your blood to clot. If your blood couldn’t clot, there’d be no stopping your blood flowing from even the most minor cut or bruise.
The process behind your blood effectively clotting is complex. A dozen or more proteins are involved, and a third of these require sufficient levels of Vitamin K if they’re to do their job properly. As mentioned in the introduction to this article, severe deficiency of Vitamin K is rarely seen in healthy adults (but can cause problems for people with certain gastrointestinal or liver diseases).
However, mild vitamin K deficiency can actually cause unwanted clotting and is comparatively more common. Our bodies typically prevent unwanted clots via a process involving the Gla protein matrix, and several other vitamin K-dependent enzyme systems. If your diet is too low in vitamin K, you may experience more of these unwanted clots – potentially putting more strain on your heart and blood vessels.
Whilst it’s difficult to prove vitamin K helps ward off the risks of heart disease, it is clear having vitamin K in your diet maintains healthy blood vessels and your blood’s clotting abilities. Foods rich in vitamin K, especially those rich in Vitamin K1 – the leafy greens – also help maintain a healthy heart among other health benefits.
Vitamin K: Supporting Your Bones
Vitamin K’s health benefits stretch beyond your blood vessels. It’s long been observed that people with vitamin K deficiency experience more severe and frequent fractures. Vitamin K has also been shown to help ward off unwanted loss of bone mass (otherwise known as osteoporosis).
Research has shown that our bone cells absorb both vitamins K1 and K2. As each has a different molecular structure, suggesting they have different roles in having healthy bones. This research has also identified Vitamin K2 subtypes called MK-4 and MK-7, which bones seem to absorb in preference over other sub-types. Our diets usually consist of about 10-25% of these K2 subtypes, with the remaining Vitamin K coming in forms less useful to our bones. However, certain foods have been shown to have higher concentrations of certain subtypes: for instance, fermented soy foods tend to have greater amounts of MK-7. This is one of the reasons some are branding fermented soy products a ‘super-food’, along with other fermented foods.
This research has found Vitamin K, especially MK-4, helps maintain healthy levels of ‘osteoclasts’. These bone cells are responsible for extracting the minerals stored in our bones and, if left unchecked, could cause massive bone loss. MK-4 helps ensure this doesn’t happen!
Vitamins K1 and K2 have also been shown to help maintain healthy bone density. The protein osteocalcin is used in a biochemical process in our bones called carboxylation. If too little osteocalcin is present during the carboxylation process, the risk of fractures is significantly increased. Vitamin K helps ensure the enzyme responsible for this process (carboxylase), ensuring our bone structure has a strong composition.
Thanks to Vitamin K’s multiple roles in ensuring healthy bones, it’s shown it can significantly increase bone density if sufficient amounts are consumed. Similarly, if too little is consumed, there are increased risks of arthritis and bone loss (osteoporosis).
Recommended Daily Intake of Vitamin K
The recommended daily intake (RDI) of Vitamin K is 90 mg for adult women and 120 mg for men. American’s typically achieve 70-90% of this. When you consider a single serving of broccoli provides more than enough of your RDI, it’s clear many of us aren’t eating many vegetables at all.
Vitamin K deficiency can also occur for people on certain medications, as they can impair the uptake of the vitamin from our diet; as can severe liver disease. However, medicines that suppress uptake of vitamins are almost always needed – and we can survive for short periods with lower intake of Vitamin K. As covered in the roles of this vitamin, it’s needed for our long term vitality.
Foods Rich in Vitamin K
Fresh green vegetables are the most accessible and richest source of Vitamin K1. Even herbs like parsley, basil and sage contain high levels of K1. A single serving (one cup) of most green vegetables – such as kale, spinach, asparagus, Brussels sprouts, cabbage, broccoli and other leafy greens – is sufficient in achieving your recommended daily intake. In fact, a single serving would often be more than enough: kale, one of the foods richest in vitamin K, provides almost ten times your RDI with just one cup!
Whilst it can be possible to have too much of a good thing, when it comes to vitamins and minerals: there’s no cause for concern with Vitamin K, with no major side-effects or known cases of people suffering ill effects from consuming too much.
Vitamin K can also be found in fruit – especially blueberries, grapes, kiwifruit and prunes. Soybeans and other legumes provide a useful source of Vitamin K2 —providing an alternative to animal derived products such as eggs, cheeses, milk, meat, fish and other dairy products.
Vegetarians Don’t Fear: It’s Unlikely You’re Lacking in Vitamin K2
We hope you don’t mind that we’ve saved this golden nugget of information till the end of this article: our body is able to convert Vitamin K1 to Vitamin K2. There should be no excuses for your diet to be lacking sufficient vitamin K to keep your bones healthy and your blood clotting when it needs to.