Whether you snag some vitamin C at the first sign of a cold or stock up on probiotics to keep your gut health in check, you’re not alone in turning to dietary supplements—an estimated 75% of Americans use them.
Among the various types, vitamin K is gaining popularity due to its potential benefits for healthy aging. Specifically, it is thought to aid in the prevention of age-related conditions such as osteoporosis and cardiovascular disease.
So, is it time to start adding more vitamin K to your diet? Here’s what you need to know.
What is vitamin K?
“Vitamin K is a fat-soluble vitamin, so your body stores it in fat tissue and the liver,” Heather Viola, DO, Primary Care Physician at Mount Sinai Doctors-Ansonia, tells Fortune.
“It is best known for its role in helping blood clot, or coagulate, properly.” Blood clotting, or coagulation, is the process that helps your body reduce bleeding from an injury.
There are three forms of vitamin K:
- Vitamin K1 (phylloquinone)
- Vitamin K2 (menaquinone)
- Vitamin K3 (menaphtone), which is a synthetic form of vitamin K sometimes found in animal feed or pet foods and is not intended for human consumption.
In addition to blood coagulation, your body needs vitamin K to help maintain strong bones. “People who have higher levels of vitamin K have greater bone density, while low levels of vitamin K have been found in those with osteoporosis,” says Viola.
There is also research indicating that vitamin K may help prevent and treat conditions such as coronary heart disease and cancer. A study published in the journal Oncology Letters found that a vitamin K2 treatment may positively inhibit the growth of cancer cells and decrease the risk of developing prostate and lung cancer.
Foods high in vitamin K
Sources of vitamin K1 include:
- Spinach
- Broccoli
- Iceberg lettuce
- Oils such as soybean and canola oil
- Leafy greens, such as collards
Vitamin K2 can be found in:
- Full-fat dairy products
- Pork
- Poultry
- Fermented foods
For adults 19 years and older, the recommended daily intake of vitamin K is 120 micrograms for men and 90 micrograms for women. “Vitamin K1 is the only form available in the U.S. as a supplement,” says Viola. “It is available as part of multivitamin complexes or alone in five-milligram tablets.”
While vitamin K deficiency in adults is rare, newborns are at greater risk due to very limited levels at birth. All newborn babies are required to receive a vitamin K shot to help prevent vitamin K deficiency bleeding (VKDB). Newborns who do not get a vitamin K shot are 81 times more likely to develop severe bleeding than those who receive it.
Vitamin K precautions
Your doctor may recommend a vitamin K supplement if you have a condition that causes excessive bleeding or prevents proper vitamin K absorption.
“People who have health problems such as gallbladder or biliary disease, cystic fibrosis, celiac disease, and Crohn's disease will benefit from a vitamin K supplement,” says Viola. She notes that taking antibiotics for long periods of time may also impair vitamin K absorption.
If you take blood thinners such as warfarin, you should talk with your doctor before taking vitamin K supplements or increasing your intake of foods with vitamin K. “People taking blood-thinning drugs should avoid extra vitamin K because it can reverse the effects of these drugs,” explains Viola.
The anti-aging benefits of vitamin K
There is promising research that vitamin K provides some defense against age-related conditions like osteoporosis, osteoarthritis, and cardiovascular disease. An encouraging study in rats even indicates that vitamin K may aid in slowing the progression of Alzheimer’s disease, although more studies are needed to determine the link.
When it comes to heart health, a study published in Open Heart suggests that increased vitamin K2 intake may reduce arterial stiffness, lower the risk of diabetes and coronary artery disease, and improve the survival rate among cardiac patients.
Since vitamin K is also a key player in maintaining bone health, those who are postmenopausal may benefit from a vitamin K supplement due to the increased risk of bone loss caused by decreased estrogen levels.
“There is increasing evidence that Vitamin K improves bone health and reduces the risk of bone fractures, particularly in postmenopausal women who are at increased risk for osteoporosis,” says Viola. An Osteoporosis International study found that taking a daily dose of 180 mcg of vitamin K2 helped reduce bone loss in healthy postmenopausal women.
Along these lines, vitamin K is also known to reduce bone fracture rates. Research has shown that low vitamin K intake has been linked to an increased risk of hip fractures in both men and women. However, Viola points out that ongoing studies are still needed for the FDA to make an official recommendation of vitamin K for patients at risk for bone loss.
Because of the increasing evidence that vitamin K is beneficial in reducing age-related issues, many people are eager to add more to their daily vitamin regimen. While most adults get sufficient amounts of vitamin K through a healthy diet, there is currently no evidence that higher intakes of vitamin K cause adverse side effects.
The bottom line? “Vitamin K supplements are relatively safe, and many people take them, especially postmenopausal women,” says Viola.
Of course, it is important to speak with your doctor before starting a vitamin K supplement. And since there seems to be an array of benefits associated with vitamin K that far outreach blood coagulation—especially when it comes to healthy aging—it certainly doesn’t hurt to bring it up at your next visit.
