Vitamin K2 could help with bone and heart health—but how do you get it?
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Half of all Americans take vitamins regularly, and if you’re one of them, you probably haven’t given too much thought about what’s in the multi you’re popping—or what’s missing from it.

Vitamins come into—and fall out of—fashion depending on the current research. That’s the reason you’ve heard of letters like C, E, and more recently, D, but not much of the rest of the alphabet. Turns out, one of those letters may be way more important that anyone’s ever realized.

“Vitamin K2 can basically keep you from getting chronic diseases,” says Sonya Angelone, R.D., a spokesperson for the Academy of Nutrition and Dietetics. “Some researchers even say heart disease and osteoporosis are vitamin K2 deficiencies.”

So why haven’t we heard of it before? Like all nutrients, it takes a while for the research to become accepted enough for doctors to start prescribing it. And right now, even healthcare professionals are confused about vitamin K.

Part of that confusion is that there are two forms of K, designated K1 and K2. K1 plays a role in the liver, and comes from plants like kale and broccoli. But K2, which is rarely found in food and manufactured in miniscule amounts in our guts, is the variety research has been most focused on lately.

On a metabolic level, K2’s basic function is to help shuttle calcium to bones and keep it out of the bloodstream. Calcium circulating in your blood is part of what forms plaque, the buildup that blocks arteries and contributes to chronic diseases including cardiovascular disease, dementia, and osteoporosis.

Results from the Rotterdam study, a fairly famous, large-scale population study conducted in the Netherlands beginning in 1990, found that individuals who took 50 micrograms of K2 a day had a 50 percent lower risk of heart disease.

K2 research is especially promising since, Angelone says, “Chronic disease is only increasing in this country. It would seem that all the current recommendations aren’t getting to the root of the problem. But K2, she says, just might.

The other reason you may not hear much about K2 is because its effects are so longterm. If you had a deficiency—which doesn’t really exist, since there’s no RDA for the vitamin at this time (although a Nordic company has been campaigning for one)—you wouldn’t know it. Skimp on vitamin C and you could get rickets, but our bodies need K2 in such small amounts, the effects of not getting enough will only manifest over years.  

“We usually talk about supplementing with things that are already in our diet,” says Angelone. “But K2 isn’t in the average Western diet.” It’s mostly found in a food called natto, a foul-smelling fermented soy product consumed in eastern Japan. Studies have found lower incidences of chronic disease there, too.

You may be able to find natto in health food stores or on Amazon, but K2 has no known toxicity level, so supplementing with it is relatively a safe bet, Angelone says. “K2 researchers give it to their kids,” she says. “I do too.”

Of course, it’s not as easy as grabbing a bottle off a shelf. K2 comes in two forms, one of which, MK4, is unstable. But you won’t find that info on the label. Angelone suggests asking your healthcare provider about MK7—but don’t be surprised if they haven’t heard of it. Still, if enough people ask, maybe practices will start to catch up with the research, and we’ll all be healthier for it.