Vitamin K – the next superstar?                       

            When vitamin K was discovered in 1929 it appeared that another puzzle had been solved but like many scientific matters it opened the door to further mysteries. A Danish scientist determined that it played a major role in the blood clotting process and named it vitamin K for koagulation. A half-century later its importance in the intricate regulation of calcium became apparent. Not only is calcium the major element in bone, it is necessary for normal heart function as well.

            Vitamin K has several variations in its chemical structure; the major ones are known in simple terms as K1 and K2. Vitamin K1 is abundant in leafy green vegetables such as kale, turnip greens, spinach and Brussels sprouts. Even though none of these is a favorite of most Americans a single serving provides several times as much vitamin K1 as is needed to prevent bleeding problems so that frank deficiency is quite uncommon.

            Vitamin K2 is found primarily in animal foods such as meat, eggs, cheese and certain types of seafood. It plays a much greater role in calcium regulation than K1 and a deficiency of vitamin K2 is associated with osteoporosis and a risk of fracture.

            Studies of vitamin K2 have revealed a calcium paradox. Persons who are deficient in this vitamin have less calcium in their bones but an excess of calcium in their blood vessels and heart valves. Many, if not most, elderly persons are deficient in vitamin K2, which could partly explain the high prevalence of osteoporosis and heart disease in this segment of our population. In a study of more than 4,000 persons in the Netherlands, those with the highest dietary intake of vitamin K2 were 57 percent less likely to suffer from coronary heart disease compared with those with the lowest intake.

            The amount of vitamin K that is needed to prevent a bleeding disorder is much less than that required for normal bone health, a finding that has not yet been reflected in dietary recommendations. Although vitamin K does not act alone to prevent osteoporosis, some authorities suggest a daily intake that is ten times the current recommendation.

            Vitamin K is a fat soluble vitamin and is more readily absorbed when a meal includes olive oil. The true Mediterranean diet derives about 40 percent of its calories from olive oil, perhaps adding to its value in preventing heart disease.