Data from participants of the Longitudinal Aging Study Amsterdam indicated that a combination of low vitamin D and K levels were associated with a 4.8 mmHg and a 3.1 mmHg increase in systolic and diastolic blood pressure, respectively, compared to higher D and K levels.
The risk of incident hypertension was also increased by 62% in people with the low D and K levels, wrote scientists from the EMGO Institute for Health and Care Research at the VU University Medical Center, and the University Medical Center Utrecht in Hypertension.
“Low vitamin D and K status are both associated with an increased cardiovascular risk. New evidence from experimental studies on bone health suggest an interaction between vitamin D and K; however, a joint association with vascular health outcomes is largely unknown,” wrote the researchers.
Their analysis indicated that, “[t]he combination of low vitamin D and K status was associated with increased blood pressure and a trend for greater hypertension risk”.
Vitamin D and K levels were assessed by measuring 25-hydroxyvitamin D (25(OH)D), the storage form of vitamin D in the body, and dephosphorylated uncarboxylated matrix gla protein (dp-ucMGP – high dp-ucMGP levels indicate low vitamin K status).
Data collected over 6.4 years indicated that low levels of vitamin D (25(OH)D less than 50 mmol/L) and vitamin K (dp-ucMGP above 323 pmol/L) were associated with increased systolic and diastolic blood levels, compared with high vitamin D and K levels.
The results show a correlation and not a causation and therefore intervention trials would be required to verify a causality.
Vitamins D & K
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. Both D3 and D2 precursors are transformed in the liver and kidneys into 25(OH)D and 1,25-dihydroxyvitamin D (1,25(OH)2D), the “active” form.
Vitamin D deficiency in adults is reported to precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases. There is also some evidence that the vitamin may reduce the incidence of several types of cancer and type-1 and -2 diabetes.
There are two main forms of vitamin K: phylloquinone (vitamin K1), which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10% of Western vitamin K consumption and can be synthesized in the gut by microflora.
Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.
Published online ahead of print, doi: 10.1161/HYPERTENSIONAHA.116.08869
“Joint Association of Low Vitamin D and Vitamin K Status With Blood Pressure and Hypertension”
Authors: A.J. van Ballegooijen, et al.