"Our findings provide one potential alternative mechanism for a putative protective effect of vitamin K in the progression of cardiovascular disease and osteoporosis, since both diseases are characterized by inflammation," the researchers wrote.
Researchers analyzed data from 1,381 participants in the Framingham Offspring study to determine blood vitamin K levels and dietary intake of vitamin K1 and vitamin D, as well as the occurrence of inflammation biomarkers. The participants had an average age of 59, and 52 percent were women.
The researchers found that higher blood levels and dietary intake of K1 was correlated with lower levels of 14 different inflammation biomarkers. After the researchers adjusted to exclude people with heart disease, increased vitamin K1 intake still correlated with lower levels of five specific biomarkers: a 15 percent reduction in CD40 ligand, 8 percent reduction in interleukin-6 concentration, 4 percent reduction in serum osteoprotegerin concentration, a 4 percent reduction in tumor necrosis factor receptor-2 and a 3 percent reduction in intracellular adhesion molecule-1 concentration.
Increased vitamin D intake was correlated with a decrease in one inflammation biomarker, urinary isoprostane.
The correlations held up even after the researchers adjusted for age, sex, body mass index, use of drugs including aspirin or statins, time of year and whether female participants were using hormone replacement therapy after menopause.
Vitamin K occurs in three main forms: phylloquinone or phytonadione, known as vitamin K1; and menaquinones, known as vitamin K2. Vitamin K2 can be synthesized by the human gut, and is also found in meat and fermented food products. Vitamin K1 is found in green leafy vegetables, including broccoli, lettuce and spinach. Vitamin K3, a synthetic form, is not recommended for humans.