Vitamin K is best known as the blood-clotting vitamin. Most of us know that leafy greens are a good source of vitamin K. The old parental mandate to eat your vegetables is partly driven by the understanding that we need to get our vitamin K.
Aside from its blood clotting function, vitamin K does have other benefits that few of us know about. Vitamin K, like all nutrients, plays an important role in many physiological processes. The body is a network of interrelated functions and few nutrients play an isolated role in how we stay healthy.
How much do we know about vitamin K? Like so many other things, we tend to take it for granted that we get all the vitamin K we need. Given that the main role of vitamin K is as essential as it is, we should probably get a better understanding of the other benefits of vitamin K.
What exactly is vitamin K? What are the hidden benefits of vitamin K? Are there different forms of vitamin K? What are the best sources of vitamin K? This article will give you the information you need to maintain your health and make sure you are getting the correct amount of vitamin K.
What is vitamin K?
Vitamin K refers to several compounds that are chemically similar. Together, these compounds work to facilitate the synthesis of specific proteins that allow for blood coagulations. The “K” refers to a Danish word, “koagulation,” which designates the primary function of vitamin K.
Research on vitamin K over the years has led scientists to understand that vitamin K plays a vital role in several other crucial physiological functions. Vitamin K is involved in the health of our bones and helps maintain the health of our circulatory system.
Vitamin k comes in two forms, vitamin K1 and vitamin K2 which we will discuss below, but both produce similar benefits. Vitamin K1 is found only in plant-based sources. Vitamin K2 can be found in some meats and dairy products.
Vitamin K health benefits
Beginning with the most obvious benefit of vitamin K, it is essential for blood clotting function. Vitamin K helps the body produce a protein called prothrombin. This is one of the most important compounds that allows blood to clot properly.
There are 13 proteins that vitamin K helps produce that are all essential for proper blood clotting. Most often, when people are prescribed medications that thin the blood (anticoagulants) they are warned about the importance of vitamin K. The main concern is that people who take anticoagulants need to take care to not alter the levels of vitamin K in their systems because it can interfere with the drugs.
If we do not get enough vitamin K blood can take longer to clot and there is a danger of hemorrhaging and excessive bleeding. This is rare, but it does occur.
Vitamin K is also involved in the synthesis of proteins in bone. Vitamin K helps produce a compound called osteocalcin that is essential for making bones strong. Studies show that higher levels of vitamin K are associated with higher bone density. This means fewer fractures, and this becomes much more important as we age.
Other studies have shown that women who get supplemental vitamin K are 30 percent less likely to break a hip than women who get less. Decreased bone density is a common problem as we age, and women are at a higher risk of decreased bone density and fractures.
Further studies reveal that men are just as likely to benefit from supplemental vitamin K as women. Research shows that men who take supplemental vitamin K are at a much lower risk of fractures than men who take none.
More recent research reveals that vitamin K is also good for your heart. Researchers have found that vitamin K is involved in the production of a group of proteins referred to as GLA proteins. These proteins appear to prevent the calcification of arteries. This is the so-called problem of hardening of the arteries that leads to serious heart disease and fatal heart attacks.
The calcification that can accumulate and lead to blocked arteries is a serious feature of heart disease. The GLA proteins that come with vitamin K tend to reduce or eliminate this calcification and the resultant blockages.
Making sure you are getting sufficient vitamin K can prevent blockages in arteries that run directly to the heart, and this can translate into real long-term heart health.
Types of vitamin K
While most dietary information on vitamin K and even dietary supplements of vitamin K will list it as one substance, there are two forms of vitamin K. Vitamin K1 and vitamin K2 are fairly distinct and are derived from different sources. The differences between the two forms of vitamin K largely involve complex chemical arrangements that have to do with the relative length of vitamin K molecules.
Also called phylloquinone, vitamin K1 is the most prominent dietary form of vitamin K. Vitamin K1 accounts for 90 percent of the vitamin K we take in. Vitamin K1 is found primarily in leafy green vegetables. We need to make sure we are eating plenty of these kinds of foods because we only absorb about 20 percent of the vitamin K1 contained in them.
Chemically, vitamin K2 is referred to as menaquinones. These differ from vitamin K1 in both their chemical structure and the way they behave in the body. The most important forms of vitamin K2 are found in meat, cheese, and eggs. They are also present in fermented foods. Many people in the western world, because of our diet, tend to be deficient in vitamin K2.
Foods high in vitamin K
As we noted above, the best sources of vitamin K are leafy greens. The recommended daily value (DV) of vitamin K is 120 micrograms. Below is a list of foods that are great sources of vitamin K with the DV percentage.
- Kale: 1 cup cooked kale 453% DV
- Spinach: 1 cup cooked 740% DV
- Collard greens: 1 cup cooked 644% DV
- Beet greens: 1 cup cooked 581% DV
- Turnip greens: 1 cup cooked 441% DV
- Broccoli: 1 cup cooked 183% DV
- Brussel sprouts: 1 cup cooked 182% DV
- Cabbage: 1 cup cooked 136% DV
- Pickled cucumbers: 1 cup 109% DV
- Asparagus: 1 cup cooked 76% DV
- Kiwi: 1 cup 60% DV
- Green beans: 1 cup cooked 50% DV
- Lettuce: 1 cup 43% DV
There are some other less likely sources of vitamin K, but many of these have grown in popularity in recent years.
- Pesto: ¼ cup 79% DV
- Kimchi: 1 cup 55% DV
- Celeriac: 1 cup 53% DV
- Edamame: 1 cup 34 % DV
Most of these foods are quite common, and it is easy to see that most of us get enough vitamin K from an ordinary but healthy diet. Yet, given the importance of vitamin K, it is a good idea to keep track of the things we are eating to make sure we are eating vitamin K rich foods.
The breakdown of foods that contain vitamin K1 and K2 is as follows:
- Leafy greens
- Soybean and canola oil
- Salad dressings made with soybean and canola oil
- Natto (fermented soybeans)
- Some meats, cheese, and eggs
Since few people in the United States eat natto, you can get vitamin K2 in a supplement that will provide you with all the vitamin K2 you would need in a day.
Vitamin K deficiency
Vitamin K deficiency in adults is quite rare. As we can see, most of us get plenty of vitamin K in an ordinary diet. However, certain medications will block the absorption of vitamin K. these include some antibiotics. Newborns and infants are at a higher risk for vitamin K deficiency because vitamin K does not cross the placenta and because breast milk contains very little vitamin K. For these reasons, newborns are often given vitamin K supplements to boost their blood clotting abilities.
In the unlikely event that someone does have a vitamin K deficiency, the consequence can be severe. Some of the symptoms of vitamin K deficiency include:
- Longer time for blood to clot. (The blood-clotting protein can be measured in a physician's office)
- Osteopenia (loss of bone mass) or osteoporosis (weak and brittle bones)
Vitamin K dosage
The recommended amount of vitamin K for adults over the age of 19 is 120 mg per day for men and 90 micrograms per day for women.
The amount of recommended vitamin K changes throughout our development. For young children up to one year of age, the recommended amount is only 2 micrograms per day. For children up through young adulthood, the range can be from 30 micrograms per day to 60 micrograms per day.
Again, since vitamin K is in so many foods that we commonly eat there is little danger of not getting enough vitamin K in your diet. There are some precautions you should take with vitamin K which we will discuss below.
What are the risks of taking vitamin K?
There is no maximum for how much vitamin K you can take because vitamin K generally does not reach a level of toxicity. However, anything can become dangerous if you take too much. Vitamin K can interact with many common drugs such as blood thinners, anticonvulsants, some drugs used to control cholesterol, and weight-loss drugs.
Blood thinners like warfarin are used to reduce the risk of developing dangerous blood clots. They reduce the ability of vitamin k to help blood clotting. If you take vitamin K supplements while taking drugs like warfarin you may reduce the effectiveness of the blood thinner. People who take drugs designed to lower cholesterol may be at risk of vitamin K deficiency. These drugs inhibit the absorption of dietary fat, and dietary fat is necessary for the absorption of vitamin K.
Vitamin K can interact with anticonvulsant drugs. If you are taking anticonvulsant drugs during pregnancy or while breastfeeding you can risk a vitamin K deficiency in a fetus or newborn. Make sure you check with your physician if you take drugs such as phenytoin or dilantin.
As with any dietary supplement, make sure you consult your doctor if you are taking any medications to make sure that the dietary supplement such as vitamin K does not interact with your medication.
Like most vitamins and nutrients, many of us tend not to think much about them unless we find that we are lacking them for some reason. Vitamin K is one of these nutrients that we take for granted because few of us ever need to think about it.
Vitamin K is so common in the foods we eat that few of us will ever deal with a vitamin K deficiency. However, since vitamin K is so incredibly important for some of the most essential functions in our bodies, we should learn to pay attention to it.
Vitamin K is most significant for its importance in the blood clotting function. Vitamin K is essential for the production of proteins that make it possible for our blood to clot and stop bleeding. One of the first symptoms of vitamin K deficiency is bleeding. If untreated or neglected, a vitamin K deficiency can lead to hemorrhaging.
Recent research has found that vitamin K has some other hidden benefits. Vitamin K, it turns out, is important to maintaining the health of our bones. Vitamin K can also help protect the heart by maintaining the health of the circulatory system to and from the heart.
It turns out that vitamin K is much more important than we once thought. Thankfully, vitamin K abounds in foods that are extremely common in our diet. Leafy greens, broccoli, green beans, and even a good pesto pasta will provide all the vitamin K you need.