Vitamin K walks to a different beat. For starters, those who discovered the vitamin didn’t follow the established nomenclature. The first vitamin named in 1912, vitamin A, started the alphabetical trend through vitamin H, until 1935, when Danish scientist Henrik Dam named vitamin K after the German word for “clotting vitamin,” Koagulationsvitamin.
Dam discovered when chickens were depleted of this fat-soluble vitamin, they developed hemorrhages and uncontrolled bleeding. Dam, along with Edward Adelbert Doisy of Saint Louis University, won the 1943 Nobel Prize for the discovery of the structure and chemical nature of vitamin K.
Their work lead to a greater understanding of how vitamin K works in aiding blood clotting. “Vitamin K plays an essential role in adding a carboxyglutamyl group to proteins which regulate blood coagulation and bleeding,” said Michael McBurney, Ph.D., FACN, head of scientific affairs, DSM Nutritional Products Inc.
Another extraordinary aspect of vitamin K is where humans source it. While one form of naturally occurring vitamin K, phylloquinone (K1) comes from foods, such as green, leafy vegetables and green tea, the other form, menaquinone (K2), comes from bacteria in the gut. This trade of human-made vitamins is only shared with vitamin D. Bacteria in the gut produce a range of vitamin K2 forms, each with side chains composed of a variable number of unsaturated isoprenoids, or chemical compounds; generally they are designated as MK-n, where n specifies the number of isoprenoids. Menaquinones can also be found in food that contains bacteria, such as cheese and natto, or in animals that also produce the vitamin via their gut bacteria.
However, it’s usually not the name or where it’s made that gets consumers thinking about vitamin K. “Interest in vitamin K has been generated by the publicity that studies receive, especially when they relate to direct human benefits such as stronger bones,” said Yi Wu, Ph.D., chief innovation director for The Wright Group. “Others having an interest include a subgroup of the population known as hemophiliacs, whose blood is missing the clotting factor that is so dependent on vitamin K.”
Frank Reilly, vice president, innovative products, The E.T. Horn Co., said interest in vitamin K follows the movement of healthier living. “There is a greater trend toward proactive health—exercising, eating right and taking supplements—and away from reactive health or the tradition of only seeing a doctor and thinking about health when faced with an ailment,” he said. “Because of this trend, there has been a greater focus in the industry on the science behind the supplements. Recently, letter vitamins, like K, have had a resurgence through research, and new information about the roles they play in our health has prompted mainstream attention.”