If there’s one vitamin you need to know more about, it’s vitamin K2. Unlike it’s vitamin K1 counterpart, vitamin K2 is rare in the Western diet and therefore hasn’t received much mainstream attention. However, emerging research shows that vitamin K2 may play an essential role in preventing bone loss, improved vascular health and reduced cancer risk.

Let’s start by differentiating between the two forms. Vitamin K1, phylloquinone, aids in blood clotting and is found mostly in leafy green vegetables such as spinach, kale, collards and broccoli. Vitamin K2, menaquinone, is the form produced by intestinal bacteria and found in natto and some fermented cheeses and animal products.

In discussing bone health and the prevention of osteoporosis, most of us are familiar with the role that calcium plays as a building block for strong bones and teeth. However, when we take a deeper dive, we see how vital vitamin K2 is as well in the overall process.

Osteocalcin is a vitamin K-dependent protein that helps create the bone matrix upon which calcium crystallizes. Essentially, osteocalcin helps to provide the ‘glue’ that holds the calcium in the bone. Without the presence of osteocalcin, the bone would be fragile and prone to breakage. Vitamin K2 is needed to activate this osteocalcin protein and regulate where calcium ends up in the body.

In studies where vitamin K2 was given along with other essential bone-building minerals, high consumption of vitamin K2 resulted in better levels of activated osteocalcin and a reduced risk of fracture.

Since often the first symptom of cardiovascular disease is a heart attack, doctors and researchers are constantly evaluating ways to detect earlier warnings. Blood cholesterol levels were used for decades, followed by measurements of c-reactive protein. Now, it seems that looking at how much calcium you have in the arteries can be just as, if not more, effective.

Calcium build-up, especially around the heart, is a huge risk factor for cardiovascular disease. Therefore, reduced accumulation of calcium in the arteries may help prevent heart disease and risk of heart attacks. In the Rotterdam study of almost 5000 men and women, those who had the highest intake of vitamin K2 were 52% less likely to develop calcium deposits in the arteries and were 57% less likely to die from heart disease over a 7-10 year period.

Unless you regularly consume liver, certain fermented cheeses or natto (a fermented soy product), then chances are you aren’t getting enough of this important nutrient. For this reason, a supplement is often recommended.

There are two main types of Vitamin K2 available for supplementation: MK-4 and MK-7. While both are forms of vitamin K2, MK-7 has been shown to be more effective than MK-4 at producing osteocaclin and reducing overall cardiovascular risk. In the studies referenced above, vitamin K2 was most often found in the MK-7 form over MK-4.

Of course, before taking any new supplements, it’s always a good idea to discuss your health history first with your doctor. Depending on your needs and current diet, adding a vitamin K2 supplement may be helpful in reducing risk of both cardiovascular incident and bone fractures.

Alex Caspero MA, RD, RYT is a Registered Dietitian Nutritionist and Yoga Teacher. She is the founder of Delish Knowledge ( delishknowledge.com ), a resource for healthy, whole-food vegetarian recipes. In her private coaching practice, she helps individuals find their "Happy Weight." 

*This article was written and/or reviewed by an independent registered dietitian nutritionist.