When it comes to the vitamin alphabet, most people lose interest by the time they reach 'E', but one vitamin that truly deserves attention is Vitamin K. Found in green leafy vegetables, vegetable oils, grains, and some meats and cheeses, Vitamin K is vital for numerous bodily functions, including wound healing, bone regeneration, and maintaining healthy blood pressure.
It achieves the latter by preventing calcium from accumulating on the walls of arteries and other major blood vessels, thereby reducing vascular stiffness and ensuring smooth blood flow. While NHS guidelines indicate that most people can obtain sufficient Vitamin K from their diet, supplements are available for as little as 3 pence per pill.
How Vitamin K Works
Jan Olav Aaseth, a professor at the University of Inland Norway, explains that the calcium removed from arteries is redirected into bones, making Vitamin K doubly beneficial. 'Vitamin K is necessary for carrying calcium away from the heart and blood vessels into bone, thereby improving both heart and bone health,' he told The Telegraph.
Although it might seem necessary to take large amounts of Vitamin K supplements daily to maintain clear and supple arteries, Professor Aaseth insists that a diet rich in vegetables can provide all the required Vitamin K. 'The problem is that modern diets might contain two small amounts of vegetables per day, for instance, broccoli, that contain Vitamin K,' he explained. Leafy greens such as spinach and kale are particularly rich in Vitamin K1.
Additional Health Benefits
Increasing Vitamin K intake does more than just improve blood flow; it has been linked to a range of positive health outcomes. Professor Penny Ward, a pharmaceutical expert at King's College London, told the Daily Mail that recent studies suggest Vitamin K may help stave off dementia. 'Observational studies suggest that adults eating a diet rich in vitamin K live longer and are less likely to develop heart disease or dementia,' she said.
Professor Ward added that Vitamin K helps 'preserve normal brain function by preventing brain cell death' and assists in clearing toxic amyloid proteins from the brain. Earlier this year, researchers found that following the MIND diet—which emphasizes Vitamin K-rich foods—could reduce Alzheimer's risk by more than half. The MIND diet, developed by researchers at Rush University and the Harvard Chan School of Public Health, combines elements of the Mediterranean and DASH diets, focusing on brain-preserving foods.
In the first analysis of its benefits, published in the journal Alzheimer's & Dementia in 2015, over 900 participants were monitored for an average of four-and-a-half years. Those who adhered most strictly to the diet reduced their risk by 53 percent.
Vitamin K also offers other health advantages. Professor Ward noted: 'General health benefits include a reduction in inflammatory proteins and improvement in insulin sensitivity, which may reduce the risk of type 2 diabetes. Vitamin K has a beneficial effect on a variety of body proteins which help to preserve healthy bone mass and, importantly, prevent the build-up of calcium deposits in arteries that can lead to heart attacks and strokes.'
Forms of Vitamin K
Vitamin K is a fat-soluble vitamin, meaning it can be stored by the body. It exists in two forms: Vitamin K1 and Vitamin K2. Vitamin K1 is found mainly in leafy green vegetables such as Brussels sprouts, broccoli, asparagus, and green cabbage. Vitamin K2 comes from fermented foods and animal products like eggs, chicken liver, and chicken thighs, as well as dairy products such as full-fat milk, yogurt, and cheeses like gouda, edam, brie, camembert, and roquefort.
Each form offers distinct benefits. Research suggests that Vitamin K1 plays a greater role in blood clotting, while Vitamin K2 may be more effective at directing calcium away from arteries and into bones.
Recommended Intake and Supplementation
The NHS states that most people can obtain sufficient Vitamin K through a balanced diet, with adults needing approximately one microgram per kilogram of body weight daily. Supplements are available online and in wellness shops, split into Vitamin K1 and K2 varieties. However, Professor Ward says getting the vitamin through food is 'easily achieved,' so there is generally 'no need' to buy supplements.
Deficiencies do occur, however. Low Vitamin K levels have been linked to bleeding disorders, poor bone development, and cardiovascular disease. Stefanos Roumeliotis, a kidney specialist at Aristotle University of Thessaloniki, told The Telegraph that '96 percent of chronic kidney disease patients are severely deficient in Vitamin K.'
Before stocking up on kale or supplements, the NHS urges caution. Supplementing with less than 1 milligram of Vitamin K is unlikely to cause harm, but people on blood-thinning medications should avoid them due to potentially harmful interactions. Warfarin, a common anticoagulant, blocks the body's use of Vitamin K. Normal dietary intake of Vitamin K can usually be maintained while taking warfarin, but sudden or significant increases in consumption should be avoided.
Professor Ward advised: 'People taking the anticoagulant warfarin should not change their Vitamin K intake without consulting their doctor, as it counteracts the effects of warfarin on blood clotting. But direct-acting anticoagulants—apixaban, rivaroxaban, or dabigatran—will not be affected, as these drugs do not interact with Vitamin K.'
