Vitamin K isn't one of the best-known vitamins, but if you're serious about maintaining healthy bones it's vital. Like B vitamins, vitamin K is a family of vitamins and K1 and K2 are the most important to know about.
While you can obtain K1 from foods like broccoli and kale, K2 is a little harder to come by, especially if you're vegetarian. K2 is naturally found in fermented foods and pasture-raised meat. Learn more about supplementing with K vitamins in this shopping guide. We've also included our top picks at the end of this article, like Bronson's Vitamin K Triple Play, which includes both K1 and K2.
Considerations when choosing vitamin K supplements
Benefits of vitamin K
Vitamin K's job in your body is to transport calcium to the bones, improve mineral density of the bones, and prevent deadly blockages caused by calcium accumulation. In addition to maintaining bone health, vitamin K promotes blood vessel health by keeping arteries clear of calcification.
Vitamin K promotes swift healing of wounds, and a deficiency of vitamin K can increase your risk of uncontrolled bleeding. Improvements in skin and whiter teeth can result from vitamin K supplementation. Lastly, vitamin K works best when paired with vitamin D, another fat-soluble vitamin, which together facilitate correct calcium absorption.
Types of vitamin K
K1 is found in foods like collard greens, spinach, kale, broccoli, green beans, strawberries, and eggs. K1 is responsible for proper blood coagulation and clotting. K1 supplements are less common than K2 vitamins because most people get enough K1 through diet alone.
K2 is good for bone and heart health and is harder to come by through food sources if you don't eat a lot of fermented foods or pasture-raised meat, making it more popular for supplementation. Within K2, there are two vitamin subtypes, called menaquinones:
Form: Vitamin K supplements typically come in capsule form. Liquid drops are also available and often formulated for infants.
Dosage: Your body only needs a miniscule amount of vitamin K, which is measured in micrograms. Adult men require a daily intake of 125 mcg and adult women require 90 mcg. Vitamin K pills often contain four to six times that amount. Drops usually contain the recommended daily amount (around 100 mcg) and can also be easily calibrated. Check the label as well as with your healthcare practitioner for proper dosage.
Additional ingredients: Many vitamin K supplements come with added vitamin D3 since these two vitamins work together synergistically. D3 is measured in IUs and can range anywhere from 400 to 5,000 IUs in supplements combined with vitamin K.
Another beneficial ingredient to look out for in liquid K supplements is coconut oil or olive oil. Because vitamin K is fat-soluble you want to take it with healthy fats to increase its absorption. Look for organic, non-GMO ingredients where possible to avoid unnecessary toxins like pesticides.
A. If you're taking blood thinners or the drug Coumadin, which slows blood clotting, vitamin K supplements can make them less effective. Drugs for cancer, seizures, and high cholesterol may also interfere as well as some antibiotics.
Our take: A no-frills K2 supplement that helps regulate calcium and aid absorption.
What we like: Inexpensive, once-a-day pill. MK7 sourced from chickpeas; soy-free. Keeps arteries from calcifying. Comes with transparency code that reveals purity of ingredients.
What we dislike: People taking statins may have adverse reactions.
Ana Sanchez is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.
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