Why little-known vitamin K2 is suddenly rising in popularity

For years, the nutrition conversation has revolved around the loudest voices, and now more are shouting out for Vitamin K among the popular contenders, as well.

Up until now, health experts have been waxing lyrical about vitamin C for immunity, vitamin D for winter survival, and magnesium for sleep and stress — and some social media credibility on the side.

Meanwhile, other nutrients have rarely been discussed by comparison, sitting in the back corners of supermarket aisles.

Vitamin K has long sat in that overlooked category. Mentioned occasionally in relation to leafy greens and blood clotting, it has never quite enjoyed the cultural glow-up of its more famous counterparts. That’s even among people who pay close attention to nutrition, as it tends to register as functional rather than exciting.

Among the various vitamins to try, vitamin K is one you shouldn't miss out on, and for good reason (gece33/Getty Images)

It turns out that part of that is down to confusion, as vitamin K is often spoken about as a single nutrient; in reality, however, it is a family of nutrients with different forms doing very different things in the body. For years, most public attention has focused on K1, the version found in vegetables like kale and broccoli.

K2, by contrast, has stayed largely out of sight, but that is starting to change.

Around the middle of the last decade, researchers began to look more closely at vitamin K2 and noticed something unusual. Unlike K1, which primarily supports blood clotting, K2 appears to play a more targeted role in directing calcium through the body.

As registered dietitian Avery Zenker told Prevention: “The main function of vitamin K1 is its role in blood clotting, while vitamin K2 is known for its role in bone and cardiovascular support.”

This calcium-handling role is what has sparked growing interest. Vitamin K2 activates proteins that help bind calcium to bones and teeth, while keeping it out of places it can cause damage, such as arteries.

Sandip Sachar, D.D.S, explains that K2 activates ‘key regulators that help bind calcium to bone and teeth, while preventing calcification in blood vessels,’ adding: “This ensures that calcium strengthens the bone and tooth structure and does not accumulate in blood vessels where it causes harm.”

Fermented soya beans (known as 'natto' in Japan) is one of the highest food sources of K2 (Koichi Kamoshida/Getty Images)

Long-term observational studies have added momentum. Those like a 2016 study published in the journal ‘atherosclerosis’, revealed that higher intakes of vitamin K2 have been associated with a lower risk of arterial disease, particularly in people with conditions like hypertension and diabetes. Notably, these protective effects were not seen with vitamin K1.

Bone health has also driven interest. Registered dietitian & consultant Amy Goodson said to EatingWell: “Vitamin K2 helps regulate calcium in the body, directing it to bones and teeth while preventing buildup in arteries and soft tissues,” while emerging research suggests benefits for bone density and fracture risk, especially later in life.

Diet has played a role in K2’s rise, too. It is found mainly in fermented foods and animal products such as eggs, cheese and liver, which many people now eat less of.

Dietitian Amy Davis told Eating Well: “Vitamin K2 is a fat-soluble vitamin that plays many different roles in the body. Vitamin K2 is found in animal foods and fermented food and can also be made by bacteria in the gut.”