New US research has found that a good intake of vitamin K, which is found in leafy greens and vegetable oils, could help reduce the risk of death as we age.
Led by researchers at Tufts University and Tufts Medical Centre, the new meta-analysis looked at 3,891 American adults aged 54 to 76, who were all free of heart disease at the start of the study.
The participants were categorised into groups according to their vitamin K blood levels, before being followed for around 13 years to assess their risk of heart disease and risk of death.
The findings, published in The American Journal of Clinical Nutrition, showed that although there was no significant association between vitamin K levels and heart disease, participants with the lowest vitamin K levels had a 19% higher risk of death, compared those with vitamin K levels that suggested an adequate vitamin K intake.
The findings also held true even after the researchers had taken into account other factors such as age, gender, body mass index (BMI), medication and smoking status.
Vitamin K is important for healthy blood vessels, with first author Kyla Shea explaining that, “The possibility that vitamin K is linked to heart disease and mortality is based on our knowledge about proteins in vascular tissue that require vitamin K to function.
“These proteins help prevent calcium from building up in artery walls, and without enough vitamin K, they are less functional.”
“Similar to when a rubber band dries out and loses its elasticity, when veins and arteries are calcified, blood pumps less efficiently, causing a variety of complications.
“That is why measuring risk of death, in a study such as this, may better capture the spectrum of events associated with worsening vascular health,” said last author Daniel Weiner, MD.
The researchers point out that as the study is an observational one, they cannot establish cause and effect, and further studies are now needed to clarify why vitamin K was linked with a lower risk of death, but not heart disease.
Vitamin K is found in leafy greens, such as lettuce, kale, and spinach, and in some vegetable oils, notably soybean and canola.