In a clinical trial published in the Journal of Nutrition, researchers found that in a group of older adults, a low vitamin D and K status was associated with increased cardiovascular disease, all-cause mortality, and increased left ventricular mass index (a negative marker of cardiovascular health).
 
The study recruited 601 participants of the Hoorn Study, who had a mean age of 70, with 50.4% women. 321 of the participants underwent a cardiogram between the years 2000-2001 and 2007-2009, with their vitamin D and K status tested from baseline until 2018. These vitamin statuses were then associated with echocardiographic measures, as well as all-cause mortality, with the results adjusted for a number of confounding variables.
 
Following the seven-year follow-up, the researchers found that a combination of adequate vitamin D and K status resulted in significant differences in positive outcomes as related to left ventricular mass index, cardiovascular, and all-cause mortality, compared to participants who had low statuses in either or both of the vitamins evaluated.
 
“The association between combined vitamin D and K status and echocardiographic measures has, to our knowledge, not been studied before,” the authors said. “A combination of both low vitamin D and K status has been investigated in relation to other parameters of cardiovascular health such as blood pressure and vascular stiffness, with results comparable to those of our study.”
 
The authors said that the observed synergistic association of low vitamin D and K status with cardiac remodeling could be explained by vitamin K’s ability to inhibit the calcification of soft tissue in the arteries, which could create a form of arterial stiffness that elevates the risk of hypertrophy and cardiac remodeling. Vitamin D has long been associated with a reduced risk of cardiovascular disease due to its role in calcium metabolism – deficiency in this vitamin is associated with arterial hypertension, type 2 diabetes, left ventricular hypertrophy, and a higher incidence of heart failure, the researchers said.
 
They concluded that joint vitamin D and K deficiency was associated with a higher risk of death than deficiency in either of the vitamins alone, because a continuous association between vitamin K status and mortality was only observed in the setting of a low vitamin D status.
 
The authors concluded that their findings should go on to inform and warrant future investigations into vitamin D and K supplementation and its impact on cardiovascular and heart disease outcomes.