Vitamin K has long been known to play an important role in the production of molecules involved in normal blood clotting. More recently, evidence has shown that Vitamin K is involved in the production of osteocalcin, a protein needed for proper bone formation. Osteocalcin has been shown to:• help cut the risk of broken bones in older adults.• help regulate the beta-cells in the pancreas that produce insulin.• signal fat cells to release adiponectin, a protein known increase insulin sensitivity.1Data from the Nurse’s Health Study found that women who consumed more green leafy vegetables, the best source of vitamin K, were less likely to develop type 2 diabetes over an 18-year period. Each daily serving of green leafy vegetables reduced the risk of developing diabetes by 10% . Data from the Framingham Offspring Study were analyzed by Tufts University research team, which found that higher vitamin K was associated with improved insulin sensitivity.2 To determine if extra vitamin K could cut the risk of developing type 2 diabetes, researchers at Tufts recruited 355 nondiabetic men and women 60 to 80 years old for a 3-year clinical trial. Half were given a supplement 500mcg of vitamin K1 (the type found in leafy vegetables) and the other half received a placebo. After 3 years, this research found that insulin sensitivity significantly improved in the men, but not the women subjects.3Bottom Line: There is already more than sufficient data that eating more green leafy vegetables improves health. They are a rich source of nutrients like potassium and magnesium that many Americans don’t get enough of. They are also rich in fiber and have a very low calorie density making them an excellent choice for weight control. Growing research suggests that green leafy vegetables may also help prevent broken bones and possibly type 2 diabetes as well because they are high in vitamin K.By James J. Kenney, PhD, RD, FACNReferences:1. Cell 2007;130:456-692. www.ajcn.org3. care.diabetesjournals.org