Scientists from the University of Bergen have found that one form of vitamin K—vitamin K2—may help reduce the risk of heart disease.
Their research showed that higher intake of vitamin K2 is linked to a lower risk of coronary heart disease.
Coronary heart disease occurs when the blood supply to the heart is blocked or reduced due to a buildup of fatty substances in the coronary arteries.
Over time, artery walls can become narrowed and hardened by these fatty deposits, a process known as atherosclerosis.
Coronary heart disease is the leading cause of death in the United States. According to the Centers for Disease Control and Prevention, about 18.2 million American adults have coronary artery disease, making it the most common form of heart disease.
Coronary artery disease is often caused by cholesterol, a waxy substance that accumulates inside the lining of the coronary arteries, forming plaque.
Vitamin K is a fat-soluble vitamin that exists in two main forms. The primary type, phylloquinone (vitamin K1), is found in green leafy vegetables such as collard greens, kale, and spinach.
The other type, menaquinones (vitamin K2), is found in certain animal products and fermented foods.
Vitamin K plays an essential role in producing proteins needed for blood clotting and bone formation.
Previous studies have also suggested that vitamin K helps regulate vascular calcification—the buildup of mineral deposits in blood vessels.
Vascular calcification occurs when calcium accumulates in the walls of arteries and veins, sometimes attaching to existing fatty plaques. Although common, these deposits can increase the risk of serious cardiovascular problems.
However, the relationship between dietary vitamin K1 and K2 intake and coronary heart disease risk has remained unclear.
In the current study, researchers followed nearly 3,000 adults aged 46 to 49 years who participated in the community-based Hordaland Health Study between 1997 and 1999, tracking them through 2009.
Participants’ diets were assessed using a food-frequency questionnaire. Information on coronary heart disease events was obtained from the nationwide Cardiovascular Disease in Norway (CVDNOR) Project.
During the 11-year follow-up period, there were 112 cases of coronary heart disease.
The researchers found no association between vitamin K1 intake and coronary heart disease risk. In contrast, higher intake of vitamin K2 was associated with a lower risk of coronary heart disease.
Further analyses confirmed that vitamin K2 intake was linked to reduced risk.
Based on these findings, the researchers concluded that higher vitamin K2 intake may protect against coronary heart disease, while vitamin K1 intake showed no clear association.
Vitamin K2 can be found in foods such as natto (a traditional Japanese fermented soybean dish), cheese, beef liver, chicken, butter, and egg yolks.
The research was published in BMJ Open and conducted by Teresa R. Haugsgjerd and colleagues.
