When it comes to essential vitamins, most people are well-aware of some of the big names like Vitamin A, B, C and D. While these four nutrients are crucial for the overall health of every human, the lesser-known Vitamin K is important, too. This nutrient is well-known in the medical community for its role in blood clotting, as well as building strong, healthy bones.
Vitamin K actually refers to an entire group of related nutrients that are naturally found in both green leafy vegetables and animal foods. Most people who follow a Western diet, though, don’t receive enough of many of the nutrients in the K-family from food sources alone. It’s often more convenient and effective to supplement, as long as a medical professional grants approval.
Want to learn more about this essential nutrient and how it benefits the body? Read on to discover everything you need to know about Vitamin K supplementation and learn whether supplementing may be right for you.
What Is Vitamin K?
Vitamin K is one of the 13 essential dietary vitamins every person needs to support regular bodily processes. It’s a fat-soluble vitamin that comes in two forms—phylloquinones, also known as Vitamin K1, and menaquinones, also known as Vitamin K2.
- In phylloquinone form, Vitamin K is found in leafy vegetables like kale, spinach and collard greens.
- In menaquinone form, Vitamin K is found in animal foods and fermented foods, and it can also be produced by naturally-occurring bacteria in the body.
Why is Vitamin K so essential to your everyday health? It’s a key nutrient that aids the body in forming various helpful proteins involved in blood clotting and building bones. Your body stores Vitamin K throughout the body—in the liver, brain, heart, pancreas and bones. Unlike other fat-soluble nutrients, this vitamin is broken down and excreted from the body very quickly, rarely reaching toxic levels even in instances of high intake.
The Health Benefits of Vitamin K
Since Vitamin K is an essential nutrient, people of all ages, men and women, need adequate levels of Vitamin K in the body to support everyday processes. Generally, adult females should consume 90 micrograms (mcg) of Vitamin K each day, while adult males should receive around 120mcg. Vitamin K benefits the body in several significant ways, including:
- Heart disease prevention. Research shows that Vitamin K may play a key role in the health of your heart. It may keep blood pressure low by preventing mineral build-up in the arteries, also called mineralization. Mineralization is a major risk factor for heart disease, and it naturally occurs with age. Maintaining adequate Vitamin K levels, especially as you age, may reduce the harmful effects of mineralization, leading to better heart health and even reducing the risk of stroke.
- Improve bone health. Scientists have discovered a link between low intake of Vitamin K and osteoporosis, reflecting the belief that Vitamin K supports and maintains healthy, strong bones. It’s even thought to improve bone density while decreasing the risk of fractures.
- Strengthen tooth enamel. Vitamin K, in particular K2, is believed to support healthy tooth enamel. Studies show that K2 can re-mineralize your teeth and prevent tooth decay. It aids in the proper absorption of minerals while pushing calcium to the teeth, strengthening the enamel and leading to better oral health overall.
- Cancer-fighting properties. Vitamin K has shown promise in the prevention and treatment of cancers, particularly prostate cancer. While research is ongoing, people with higher intakes of Vitamin K may be less likely to develop and die of cancer.
- Cognitive boosts. For older adults in particular, higher levels of Vitamin K are linked with better cognitive performance, particularly improved episodic memory. In one study, healthy participants 70 years and older who had the highest levels of Vitamin K1 showed the best performance in terms of verbal episodic memory.
Maintaining adequate Vitamin K levels in the body provide a whole host of health benefits, especially for older adults. As you age, it’s important to keep tabs on your daily Vitamin K intake, as well as your intake of other essential nutrients, to support regular bodily processes and healthy aging.
The Difference Between Vitamins K1 and K2
Most people don’t know the term “Vitamin K” refers to a group of several vitamins that offer a range of health benefits. The two main forms of the nutrient found in a balanced diet are Vitamin K1 and Vitamin K2.
Vitamin K1 is the most important form of Vitamin K found in the human diet, and it’s produced by plants. K1 makes up about 75-90% of all forms of Vitamin K people consume. Several whole foods are rich in K1, and each value represents the amount of the nutrient in one cup of the cooked vegetable:
- Kale: 1,062 mcg
- Collard greens: 1,059 mcg
- Spinach: 889 mcg
- Turnip greens: 529 mcg
- Broccoli: 220 mcg
- Brussels sprouts: 218 mcg
While Vitamin K2 shares a similar structure with Vitamin K1, they’re found in completely different food sources. Vitamin K2 occurs in many fermented foods and animal products. It’s also produced naturally by gut bacteria. K2 is further broken down into several subtypes, called menaquinones (MKs). They’re classified by the length of their side chain and range from MK-4 to MK-13. You’ll find Vitamin K2 in 3.5 ounces of the following foods:
- Natto: 1,062 mcg
- Pork sausage: 383 mcg
- Hard cheese: 76 mcg
- Pork chop (with bone): 75 mcg
- Chicken (leg/thigh): 60 mcg
- Soft cheese: 57 mcg
- Egg yolk: 32 mcg
While all forms of Vitamin K work to activate proteins that contribute to blood clotting and heart and bone health, there are differences in absorption and transport between Vitamin K1 and K2. Generally, Vitamin K absorption is poor, with some research showing that only 10% of K1 in the foods you eat is actually absorbed.
While less is known about how the body absorbs K2, it’s believed to be better absorbed since it’s found in foods that are high in fat. Since Vitamin K is a fat-soluble dietary vitamin, it follows that this form of the nutrient is absorbed more readily when eaten with dietary fat.
Possible Interactions and Side Effects
Looking to boost your Vitamin K levels to take advantage of various health benefits? You should always talk to your doctor first since there are possible interactions between the nutrient and certain medications. Use caution and get a healthcare provider’s approval before taking Vitamin K with:
- Antibiotics: Some antibiotics, particularly cephalosporins, reduce absorption of Vitamin K in the body. Your doctor should monitor your Vitamin K levels, since these drugs not only kill harmful bacteria but also Vitamin K-activating bacteria.
- Phenytoin: It’s harder for the body to use Vitamin K if you take phenytoin, an anticonvulsant. Taking the medication during pregnancy can deplete Vitamin K levels in newborns.
- Warfarin: Blood-thinning medications are less effective when Vitamin K levels are high. You should not take Vitamin K supplements while undergoing warfarin therapy, and you should also avoid foods that are high in the nutrient, such as an excess of dark leafy green vegetables and dairy foods.
- Orlistat and Olestra: Both orlistat and olestra prevent absorption of fat and reduce the body’s ability to absorb fat-soluble nutrients like Vitamin K.
How Much Vitamin K Should You Take?
While most people receive enough Vitamin K from diet alone, there are some cases where supplementing is a good idea. People with digestive problems like celiac disease or Chron’s, people who are malnourished and people who drink alcohol heavily should carefully watch their Vitamin K levels and consider supplementing your dietary Vitamin K intake when necessary.
Healthy adult women should take a supplement that provides 75 mcg of Vitamin K per day, while males should take around 120 mcg per day. As noted above, it’s hard to reach toxic levels of Vitamin K in the body since it’s so readily absorbed and excreted.
Since Vitamin K is fat soluble, it’s best to take it with a meal that contains fat for optimal absorption. You can take a Vitamin K supplement any time of the day, as long as you’re doing so with a meal or snack that contains fat.
If at all possible, take Vitamin K dietary supplements at a different time of day than you take other fat-soluble vitamins like E and A (if you take them). In contrast, if you take a Vitamin D supplement, try to take it along with Vitamin K since the two nutrients work synergistically to support healthy bones.
How to Choose Quality Vitamin K Supplements
If you’re looking to increase your Vitamin K levels, it’s often hard to do so through diet alone. Not only does the body have trouble absorbing nutrients in the K1 group, but you’ll also have to eat plenty of fats to consume enough Vitamin K2. It’s often easier and more effective to supplement.
If you’re considering supplementing with Vitamin K, talk to your doctor first not only to make sure if it’s right for you, but also to determine which form of Vitamin K you need the most. You may need to boost your intake of K1, or you may just need to target adequate intake of specific menaquinones (MKs).
As you choose a supplement, keep in mind that supplements typically come in a capsule form, but liquid drops are also available, and are usually specially-formulated for infants. Most Vitamin K pills contain much more than the required daily amount, while drops typically contain the exact amount of the nutrient you need each day. Drops can also be easily calibrated if you need a more precise dosage.
Remember to also look for an all-natural supplement, as it’s more readily absorbed by the body. All-natural options have a longer half-life in the body and provide enhanced benefits for bone mineral density and additional benefits for blood vessels.
The Bottom Line on Vitamin K Dietary Supplements
Ready to take full advantage of the benefits of Vitamin K by supplementing? Before you do, get a healthcare provider’s opinion first. While supplementing is safe and effective for most people, every body is different, and your doctor can tell you the best course of action for your personal situation. If you receive approval, take your time to find an all-natural Vitamin K supplement that provides your body with the most benefits from the nutrient.