Are you getting enough vitamin K? Probably, thanks to these foods in your diet.

According to a 2021 Consumer Survey on Dietary Supplements, eight out of 10 U.S. adults take some form of vitamin or mineral supplement. And more than half of U.S. adults take multivitamins to the tune of $50 billion annually in sales.

While many of the nutrients derived from supplements can be obtained naturally through a healthy diet, supplementation is still advised for some people under some conditions.

In the case of vitamin K, most adults don’t need to supplement the nutrient in addition to their diet, but for newborns, the supplementation of vitamin K could become a matter of life or death.

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What is vitamin K?

Vitamin K is a fat-soluble vitamin that comes in two forms: phylloquinone and menaquinones. Both are used by the body to form clots to reduce bleeding when injured. Vitamin K is found in the brain, liver, heart, pancreas and bones. It’s broken down by the body very quickly so it rarely reaches toxic levels.

What does vitamin K do in the body?

In addition to its cardiovascular benefits of helping blood to clot normally, vitamin K is also an essential nutrient for bone health because it increases bone mineral density and reduces fracture rates. One type of vitamin K, called K2, has also proven to be useful in helping the nearly half of Americans that are deficient in vitamin D. “Vitamin D promotes the absorption of calcium and its deposition in bone, but if this system goes awry, calcium can deposit in the arteries which increases the risk of calcification,” explains Josh Redd, NMD, the founder of RedRiver Health and Wellness and author of “The Truth About Low Thyroid.”

“Vitamin K2 helps to prevent this by activating a protein that directs calcium toward the bones,” says Redd. Indeed, research has shown that getting enough vitamin K2 in one’s diet along with vitamin D may help strengthen bones to reduce breaks.

Beyond its roles in blood clotting and bone maintenance, vitamin K may have other health benefits as well. For instance, because of encouraging observational trials, vitamin K is sometimes promoted as a way to lower one’s risk of arthritis or dementia, “but observational studies do not establish causation,” explains Sarah Booth, PhD, center director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. For that reason, she says more research is needed before such benefits can be known for sure.

What are signs of vitamin K deficiency?

While most adults get enough vitamin K from a healthy diet, the Centers for Disease Control and Prevention (CDC) warns that “babies are born with very small amounts of vitamin K in their bodies, which can lead to serious bleeding problems.” Because of this, the agency recommends getting a single, intramuscular dose of vitamin K at birth. “This is considered a safe dose,” says Booth. “Recent trends in a small number of parents refusing (the shot) for their newborns has resulted in an increase in vitamin K-deficiency bleeding. This is entirely preventable.”

Beyond a potentially fatal vitamin K deficiency in babies, vitamin K supplementation “may also be needed for those who do not absorb fat well or for people in whom the pancreas is not functioning normally,” says Kate Zeratsky, a registered dietitian nutritionist at Mayo Clinic in Rochester, MN. “Amounts and types of supplements should be recommended by one’s health care provider,” she adds.

What foods are high in vitamin K?

While some such people may want to consider vitamin K supplementation, most adults don’t need to. “Our gut (intestine’s) bacteria can produce vitamin K, and our body also recycles vitamin K, making a deficiency uncommon,” says Zeratsky.

Those still needing to increase their intake of the nutrient can do so naturally by eating the right foods. Vitamin K is found in leafy green vegetables such as spinach, kale, Brussels sprouts, and broccoli and in fruits such as kiwi, avocado and blackberries. Zeratsky says: “Before considering a supplement, consider food.”