The combination of low vitamin D and K status was associated with increased blood pressure and a trend for greater hypertension risk new research published in the journal, Hypertension, reports.
Studying a cohort from the Longitudinal Ageing Study Amsterdam (LASA) (n = 231) which began in 2002-2003, results showed that both systolic and diastolic blood pressures were highest in the low vitamin D and low vitamin K (dephosphorylated uncarboxylated matrix gla protein) status group. During follow up which took place in three cycles – 2005-06, 2008-09, and 2011-12 - the average increase in systolic and diastolic blood pressure was 7.4±17.3 and 2.5±9.7.
"In the current study, we reported associations of serum 25(OH)D (vitamin D) and dp-ucMGP (vitamin K) with blood pressure and incident hypertension in a population-based cohort with serial follow-up in older men and women. The combination of low vitamin D (<50 nmol/L) and low vitamin K (≥323 pmol/L) status was associated with increased systolic and diastolic blood pressure, with a similar trend for incident hypertension, albeit not statistically significant," the researchers reported.
"To our knowledge, the importance of optimal vitamin D and K concentrations on blood pressure and incident hypertension has thus far only been studied in isolation. Previous prospective studies have reported lower plasma vitamin D concentrations to be associated with higher hypertension risk and higher dp-ucMGP concentrations to be associated with arterial stiffness and a higher risk of coronary artery calcification."
The authors suggest the potential mechanism to explain the joint association of vitamin D and K is via stimulation of the γ-carboxylase system of vitamin K–dependent proteins as two of these proteins are Gla-containing proteins - osteocalcin and MGP- which play a role in the development of coronary artery disease.
"Osteocalcin has been shown to have a regulatory role in bone mineralization and calcium ion homeostasis with the potential to prevent calcium build-up in soft tissues, thereby, preventing vascular calcification and MGP limits calcium incorporation into the extracellular matrix of soft tissues, thus, acting as a potent inhibitor of soft tissue calcification," the authors explained.
"Activation of osteocalcin and MGP is dependent on vitamin K, which acts as a cofactor in the carboxylation cycle. Low expression or inactivation of vitamin K–dependent proteins can lead to vascular stiffness, which can increase blood pressure and incident hypertension risk. Circulating vitamin D has been shown to increase MGP mRNA expression in humans."
As the first study investigating joint associations of vitamin D and vitamin K in relation to cardiovascular health, the authors concluded that further prospective studies are needed to better understand the clinical implications of this relationship to promote cardiovascular health.