In the fashion world, trends come and go, and the dietary supplement industry shares the same “what’s hot” and “what’s not” faddism. For the last three years, vitamin D has soaked up the spotlight. The nutrient gained attention from an increasing number of research studies showing benefit to a myriad of diseases—cancer, autoimmune disorders, immune health, depression, and last but not least, death. But like bell bottom pants, vitamin D’s staying power may be short-lived. Word on the street is that vitamin K is the new D.
It started with a cluster of research done on vitamin K in the early 2000s. A 2003 study in the American Journal of Clinical Nutritionfound low dietary intake of vitamin K was associated with low bone mineral density in women, which validated similar outcomes in other studies and associations between low vitamin K intake and a higher risk of hip fracture. A year later, the same journal published a study showing girls with a better vitamin K status had better bone turnover. But bone health wasn’t the only association researchers noticed. Over the next few years, studies on vitamin K would show associations between high vitamin K status and reduced risk of prostate, lung, and liver cancers, and protection against coronary heart disease.
Two forms of vitamin K exist: vitamin K1 (phylloquinone) is found in leafy green vegetables. Vitamin K2 (menaquinone) is synthesized by bacteria and is found in fermented soybeans and certain cheeses. Much of the research done has looked at vitamin K2. Both forms are essential for the proteins involved in blood clotting and are necessary for proteins that are needed to form bone. Although vitamin K is fat-soluble, the body does not store much and it can be depleted without regular dietary intake. However, it may be difficult to get in the daily diet.
If you are starting to think vitamin K sounds a lot like vitamin D’s recent milieu, you’re right. While more research is needed (isn’t that always the case?), expect to hear more about vitamin K in both research and product developments.
By Erin Kelley, MS, RD