Researchers at Australia’s New Edith Cowan University (ECU) found that people who eat a diet rich in vitamin K have up to a 34% lower risk of atherosclerosis-related cardiovascular disease.
They examined data from more than 50,000 people taking part in the Danish Diet, Cancer, and Health study over a 23-year period and investigated whether people who ate more foods containing vitamin K had a lower risk of cardiovascular disease related to atherosclerosis (plaque build-up in the arteries).
There are two types of vitamin K found in foods we eat: vitamin K1 comes primarily from green leafy vegetables and vegetable oils while vitamin K2 is found in meat, eggs and fermented foods such as cheese. The study found that people with the highest intakes of vitamin K1 were 21% less likely to be hospitalised with cardiovascular disease related to atherosclerosis. For vitamin K2, the risk of being hospitalised was 14% lower.
This lower risk was seen for all types of heart disease related to atherosclerosis, particularly for peripheral artery disease, at 34%.
ECU researcher and senior author on the study Dr Nicola Bondonno said the findings suggest that consuming more vitamin K may be important for protection against atherosclerosis and subsequent cardiovascular disease.
"Current dietary guidelines for the consumption of vitamin K are generally only based on the amount of vitamin K1 a person should consume to ensure that their blood can coagulate," she said. "However, there is growing evidence that intakes of vitamin K above the current guidelines can afford further protection against the development of other diseases, such as atherosclerosis.
"Although more research is needed to fully understand the process, we believe that vitamin K works by protecting against the calcium build-up in the major arteries of the body leading to vascular calcification."
University of Western Australia researcher Dr Jamie Bellinge, the first author on the study, said the role of vitamin K in cardiovascular health and particularly in vascular calcification is an area of research offering promising hope for the future.
"Cardiovascular disease remains a leading cause of death in Australia and there's still a limited understanding of the importance of different vitamins found in food and their effect on heart attacks, strokes and peripheral artery disease," Bellinge said. "These findings shed light on the potentially important effect that vitamin K has on the killer disease and reinforces the importance of a healthy diet in preventing it."
Next steps in the research
Bondonno said that while databases on the vitamin K1 content of foods are very comprehensive, there is far less data on the vitamin K2 content of foods. Furthermore, there are 10 forms of vitamin K2 found in our diet and each may be absorbed and act differently within our bodies.
"The next phase of the research will involve developing and improving databases on the vitamin K2 content of foods. More research into the different dietary sources and effects of different types of vitamin K2 is a priority," he added.
Vitamin K Intake and Atherosclerotic Cardiovascular Disease in the Danish Diet Cancer and Health Study
Jamie W. Bellinge, Frederik Dalgaard, Kevin Murray, Emma Connolly, Lauren C. Blekkenhorst, Catherine P. Bondonno, Joshua R. Lewis, Marc Sim, Kevin D. Croft, Gunnar Gislason, Christian Torp‐Pedersen, Anne Tjønneland, Kim Overvad, Jonathan M. Hodgson, Carl Schultz, Nicola P. Bondonno
The research was a collaboration with researchers from the University of Western Australia, Royal Perth Hospital, Herlev & Gentofte University Hospital in Denmark and the Danish Cancer Society Research Centre.
Published in the American Heart Association Journal 7 August 2021
Dietary vitamin K (K1 and K2) may reduce atherosclerotic cardiovascular disease (ASCVD) risk via several mechanisms. However, studies linking vitamin K intake with incident ASCVD are limited. We aimed to determine the relationship between dietary vitamin K intake and ASCVD hospitalisations.
Methods and results
In this prospective cohort study, participants from the Danish Diet, Cancer, and Health Study, with no prior ASCVD, completed a food‐frequency questionnaire at baseline and were followed up for hospital admissions of ASCVD; ischemic heart disease, ischemic stroke, or peripheral artery disease. Intakes of vitamin K1 and vitamin K2 were estimated from the food‐frequency questionnaire, and their relationship with ASCVD hospitalisations was determined using Cox proportional hazards models.
Among 53 372 Danish citizens with a median (interquartile range) age of 56 (52–60) years, 8726 individuals were hospitalized for any ASCVD during 21 (17–22) years of follow‐up. Compared with participants with the lowest vitamin K1 intakes, participants with the highest intakes had a 21% lower risk of an ASCVD‐related hospitalisation (hazard ratio, 0.79; 95% CI: 0.74–0.84), after multivariable adjustments for relevant demographic covariates. Likewise for vitamin K2, the risk of an ASCVD‐related hospitalisation for participants with the highest intakes was 14% lower than participants with the lowest vitamin K2 intake (hazard ratio, 0.86; 95% CI, 0.81–0.91).
Risk of ASCVD was inversely associated with diets high in vitamin K1 or K2. The similar inverse associations with both vitamin K1 and K2, despite very different dietary sources, highlight the potential importance of vitamin K for ASCVD prevention.
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