If there’s one vitamin that hasn’t gotten the respect it deserves, it’s vitamin K. For years, it’s been viewed as the “redheaded stepchild” in the world of supplements and nutrition. Lately though, vitamin K is enjoying a resurgence of sorts. Research is starting to reveal the very diverse benefits of this important nutrient—and some of them may surprise you.
Essential for Clotting
Vitamin K was originally discovered in 1942 by biochemist Henrick Dam. He observed that, when chickens were fed a cholesterol- and fat- free diet, they had problems with excessive bleeding and slowed blood clotting. This led to the discovery of a substance in fat that aided in blood clotting, or coagulation—and that substance was vitamin K.
Coagulation is an important process that prevents excessive bleeding after suffering an injury. Turns out that vitamin K is an important player in a process that promotes the activation of proteins called gamma-carboxyglutamate (Gla). Some of the most widely studied Gla proteins are those involved in coagulation.
Benefits Beyond Coagulation
But vitamin K is no one-trick pony. There are many other proteins that depend on vitamin K to function property, and they play roles in bone, heart, and cognitive health, and even diabetes.
Bone Health
One of these proteins is called osteocalcin. This protein is produced by osteoblasts—cells that build strong new bone.
Osteocalcin helps to move calcium from your blood stream and into your bones, where it promotes remineralization and formation of healthy new bone. Research has shown that low levels of vitamin K are associated with bone loss and osteoporosis, while maintaining adequate levels of K can help to prevent bone loss, especially in those who already have osteoporosis.
In one such study, a meta-analysis of 19 studies involving a total of 6,759 people, researchers concluded that vitamin K aids in the maintenance and improvement of bone mass density and the prevention of fractures in postmenopausal women who already have osteoporosis.1
Diabetes
That’s not all. Osteocalcin’s benefits extend beyond bone and into blood sugar too. Studies have shown that vitamin K can help improve insulin sensitivity and glucose metabolism, lower blood lipids, and prevent diabetes, through this K-dependent protein.2
Heart Health
A 2017 study concluded that, “vitamin K has a potential role in cardiovascular health, particularly in high-risk and chronic kidney disease populations.3
Vitamin K activates a protein known as matrix Gla (MGP). Unlike osteocalcin, which pulls calcium into bones, MGP prevents the deposition of calcium in blood vessels. Otherwise, the buildup of calcium in the arteries can result in stiffening of arteries (atherosclerosis), which is a major risk factor for heart disease.
In a three-year study, a group of women took either vitamin K supplements or placebos. Those taking the K had a statistically significant reduction in artery stiffness—and the placebo group had an increase.4
Cognitive Health
Emerging research has found that levels of vitamin K tends to be lower in people with Alzheimer’s disease compared to cognitively healthy individuals.
Additionally, a study of 192 people aged 65 and older discovered that those who consumed the highest amounts of vitamin K had better cognition and behavior than those with the lowest intake.5
Getting Enough K
There are two forms of vitamin K: K1 (phylloquinone) and K2 (menaquinone).
K1 is found in plant foods. Some of the best sources include collard greens, kale, broccoli, spinach, and Brussels sprouts. Keep in mind, cooking or sautéing your veggies in a healthy fat, such as olive or avocado oil, helps with the absorption of vitamin K. If eating raw, add a healthy fat to your plate, such as sliced avocado, or drizzle the vegetables with the oil.
K2 occurs in animal products (meat, eggs, and dairy) and some fermented foods (natto, a fermented soybean product, is the best source).
K2 is also created by bacteria in the intestinal tract. This is yet another reason to make sure you have a robust colony of beneficial microbes in your gut. If you don’t already, consider taking a probiotic supplement, like Newport Natural Health’s Microencapsulated Probiotic with FOS, to support and promote a healthy microbiome. It’s made from six of the hardiest, most beneficial probiotic strains available today. Each one is microencapsulated to ensure safe travel through your powerful stomach acids and into your small intestines where they do their best work.
If you’d prefer to supplement with K2 directly, the recommended daily intake is 120 mcg for men and 90 mcg for women. If you eat your veggies every day, chances are you’re getting enough. But if your diet falls short—or if you have a known deficiency—talk to your doctor about supplementation. (Older adults tend to fall into this category.)
There are several types of vitamin K supplements available, but K2 (a form of K2 called MK-7 absorbs and works the best in the body) is better at raising blood levels than other forms. Use as directed, but typically the daily dose is 100-200 mcg daily.
A Warning If You’re on Blood Thinners
The anticoagulant medication Coumadin (warfarin) prevents harmful blood clots by blocking the action of vitamin K. If you take this drug, you need to closely monitor your intake of vitamin K.
By no means should you avoid foods that contain vitamin K, as this would mean avoiding your greens—which have far more benefits than just vitamin K. However, you should try to remain consistent with the amount of K-rich foods that you consume every day. If you start to eat more or less, you may need to have your warfarin dosage adjusted. Be sure to keep an open dialogue with your doctor about this. Newer generation blood thinners like Xarelto and Eliquis aren’t affected by vitamin K.
References
- Huang ZB, et al. Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials. Osteoporos Int. 2015 Mar;26(3):1175-86. Last accessed 1/16/20.
- Li Y, et al. Effect of vitamin K2 on type 2 diabetes mellitus: a review. Diabetes Res Clin Pract. 2018 Feb;136:39-51. Last accessed 1/16/20.
- van Ballegooijen AJ and Beulens JW. The role of vitamin K status in cardiovascular health: evidence from observational and clinical studies. Curr Nutr Rep. 2017;6(3):197-205. Last accessed 1/16/20.
- Knapen MH, et al. Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomized clinical trial. Thromb Haemost. 2015 May;113(5):1135-44. Last accessed 1/16/20.
- Chouet J, et al. Dietary vitamin K intake is association with cognition and behaviour among geriatric patients: the CLIP study. Nutrients. 2015 Aug;7(8):6739-50. Last accessed 1/16/20.
Last Updated: January 30, 2020
