Medically CitedOverview
Following a healthy, balanced diet helps provide your body with a range of nutrients required for optimal health and functioning. While we hear a lot about potent vitamins like A, C, and D, the key nutrient vitamin K is less often mentioned but no less important.
When it comes to supporting healthy blood clotting and keeping your bones strong, vitamin K is essential, and it may offer other benefits like supporting heart health and enhancing cognitive function. In this review, we examine the properties and health advantages of vitamin K, the recommended daily intake, and the best sources of this key nutrient.
What is Vitamin K?
Vitamin K is a fat-soluble nutrient produced in small amounts in the body and primarily derived from foods or supplements. It assists in producing key proteins required for proper blood clotting, such as prothrombin, and others like osteocalcin, which support bone health.
While discussed as one nutrient, vitamin K is a group of compounds that exists in two forms. Vitamin K1, or phylloquinone, is found in leafy green vegetables like kale and spinach, and vitamin K2, or menaquinone, exists primarily in animal products and fermented foods. Some sources indicate that K2 is better absorbed by the body and may offer stronger benefits.
Vitamin K also has antioxidant properties, helping to lower oxidative stress in the body, promote repair, protect cells from damage, and prevent cell death. In addition, it may offer benefits to cardiovascular and brain health and impact insulin levels. Let’s examine the key vitamin K benefits in detail.
What Are the Benefits of Vitamin K?
Vitamin K: Key to Strengthening Bones and Supporting Health.
The primary health advantages of vitamin K include the following:
Helps Blood Clotting
When it comes to blood clotting, vitamin K1 plays a more central role than K2. It assists in the synthesis of clotting factors in the liver, activating proteins like prothrombin, which bind to calcium. As we said in our review of Good Dirt Vitamins, this helps to stimulate the process of hemostasis to stop wounds from bleeding. A research review in the American Journal of Surgery discusses the important role of vitamin K in blood coagulation in detail.
Supports Bone Health
Vitamin is essential in the production of the protein osteocalcin, which bonds to calcium to strengthen the bones and enhance bone mineral density. Evidence indicates that adequate intake may help decrease fracture risk, in particular in individuals with osteoporosis.
A systemic review and meta-analysis published in the Archives of Internal Medicine found that supplementation with phytonadione and menaquinone helps prevent bone loss and decrease fracture risk.
In addition to upping your intake of vitamin K, you can strengthen your bones naturally with diet, exercise, and lifestyle changes recommended by experts.
Supports Cognitive Function
Vitamin K is important in brain cell development, and it has antioxidant properties that lower oxidative stress, helping to support the health of brain cells, decrease cell death, and reduce inflammation.
A research review published in Frontiers in Neurology concluded that there is a correlation between vitamin K and cognitive performance. In addition, evidence indicates that higher vitamin K levels may decrease the risk of neurodegenerative conditions like dementia.
Supports Heart Health
Vitamin K helps support the cardiovascular system by regulating calcium homeostasis, as a review in BMJ Journals explains. This helps decrease arterial stiffness and prevent calcification in the blood vessels and valves to support overall heart health and function. Some research supports the potential benefits of vitamin K2 in decreasing the risk of cardiovascular disease.
Helps Balance Blood Sugar Levels
By lowering inflammation and oxidative stress in the body, vitamin K may improve glucose metabolism, decrease insulin resistance, improve insulin production after eating, and potentially decrease the risk of diabetes mellitus. A research review published in Nutrients concluded that supplementation with vitamin K may help slow the progression of type 2 diabetes.
How Do You Get Vitamin K?
Essential Vegetables High in Vitamin K for Better Health.
You can derive your vitamin K in 2 ways: by adding foods high in this nutrient to your diet and/or by taking a dietary supplement. Including healthy vitamin K foods is the best way to get your daily intake.
Registered dietitian Julia Zumpano, RD, LD, explains: “There’s no shortage of delicious and widely available foods that contain vitamin K. Vitamin K helps with some of our body’s most critical functions, so we need to take it seriously. Some of the best choices include:
Vitamin K1
- Cooked kale
- Cooked collard greens
- Cooked broccoli
- Cooked spinach
- Raw arugula
- Kiwi
- Asparagus
- Figs
- Vegetable oils
Vitamin K2
- Natto fermented soybean
- Organ meats
- Butter
- Hard cheeses
- Soft fermented cheeses
- Fatty fish
- Fermented milk
- Sauerkraut
How Much Vitamin K Should You Take?
The required intake of vitamin K varies by age and gender. According to the National Institutes of Health, the daily recommended vitamin K dosage for adults 19 and older, including both food and supplement forms, is as follows:
- Men:120 mcg
- Women: 90 mcg
- Pregnant Women: 75 mcg
- Breastfeeding Women: 90 mcg
When you take vitamin K in supplement form, it’s important to take it with a fatty food source like avocado or nuts to boost absorption, as it is a fat-soluble nutrient. How do you know if you are getting enough? Signs of a vitamin K deficiency may include:
- Excess bleeding from wounds or after surgery
- Nosebleeds
- Bruising on the face or around the head
- Heavy menstrual periods
- Dark stools
- Pale skin
- Fatigue and/or difficulty sleeping
If you experience these symptoms and think your vitamin K levels may be low, see a physician for a blood test and discuss possible medical causes. If suitable, consider taking a dietary supplement to increase your intake.
Safety and Side Effects
Both vitamins K1 and K2 are metabolized quickly and excreted by the urine, although K2 stays in the body somewhat longer. For this reason, there is not a huge risk of overdose, but it’s important to try to stick to the recommended daily intake.
While both forms are safe and have limited symptoms, some users may experience mild vitamin K side effects like:
- Muscle stiffness
- Irritability
- Reduced appetite
- Gastrointestinal issues like diarrhea
Medical issues that preclude taking a vitamin K supplement or consuming excess amounts include liver or kidney disease and some genetic conditions. In addition, individuals taking anticonvulsants, blood thinners like warfarin, or cholesterol-lowering medications should avoid excess vitamin K.
FAQs about Vitamin K
Q: What Does Vitamin K Do?
A: The most important functions of vitamin K are blood clotting and supporting bone health, but it also has benefits for the heart and brain and may help balance blood sugar levels.
Q: Should I Take a Vitamin K Supplement With Food?
A: Yes, vitamin K is a fat-soluble vitamin, so you should take it with food that contains (ideally healthy) fats to boost absorption, like avocado, nuts, or peanut butter.
Q: What Food is Highest in Vitamin K?
A: The richest source is a fermented soybean called Natto, but other vitamin K foods include leafy greens like kale and spinach, eggs, cheese, meat, pickles, and beet greens.
Q: How Do I Know If I Need More Vitamin K?
A: Signs of a possible vitamin K deficiency may include pale skin, nosebleeds, frequent bruising, and dark stools. If you have any of these symptoms and think you may be deficient, see a physician for testing and to discuss possible supplementation.
Q: Should Older People Take Vitamin K?
A: With the approval of a physician, seniors may consider taking a vitamin K supplement if they are not getting enough from diet alone. Evidence indicates it may help strengthen the bones, decrease the risk of osteoporosis, and support cognitive health.
Conclusion
Vitamin K plays a central role in blood clotting and bone health, and it also helps support the heart, sharpen cognitive function, and balance blood sugar levels. The best way to derive it is from vitamin K-rich foods like leafy greens, meats, cheeses, and soybeans, however, if you do not get enough from these sources, consider taking a dietary supplement.
Consult with a healthcare practitioner if you are concerned about your vitamin K intake to get your levels tested and discuss possible supplementation.
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10 sources
We review published medical research in respected scientific journals to arrive at our conclusions about a product or health topic. This ensures the highest standard of scientific accuracy.
[2] Vitamin K and its Role in Blood Coagulation: https://www.americanjournalofsurgery.com/article/S0002-9610(42)90956-5/abstract
[3] Vitamin K and the Prevention of Fractures: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/410550
[4] The Relationships Between Vitamin K and Cognition: A Review of Current Evidence: https://pmc.ncbi.nlm.nih.gov/articles/PMC6436180/
[5] Vitamin K2—A Neglected Player in Cardiovascular Health: A Narrative Review: https://openheart.bmj.com/content/8/2/e001715
[6] Association of Dietary Vitamin K and Risk of Coronary Heart Disease in Middle-Age Adults: The Hordaland Health Study Cohort: https://pmc.ncbi.nlm.nih.gov/articles/PMC7247390/
[7] Beneficial Effects of Vitamin K Status on Glycemic Regulation and Diabetes Mellitus: A Mini-Review: https://pmc.ncbi.nlm.nih.gov/articles/PMC7469006/
[8] Top Benefits of Vitamin K: https://health.clevelandclinic.org/vitamin-k
[9] Vitamin K: https://ods.od.nih.gov/factsheets/VitaminK-Consumer/
[10] The Health Benefits of Vitamin K: https://pmc.ncbi.nlm.nih.gov/articles/PMC4600246/
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