The little-known vitamin essential for heart health

There is one key dietary change that can slash your risk of dying prematurely from a heart attack or stroke, yet few of us have heard of it. Simply upping the amount of vitamin K by consuming more leafy green vegetables, as well as eggs and cheese, can make a drastic long-term difference when it comes to preventing your arteries from becoming clogged. This is because vitamin K plays a vital role in preventing artery calcification: the invisible accumulation of hard calcium deposits in the walls of major blood vessels that can progressively restrict blood flow.

As Jan Olav Aaseth, a professor at the University of Inland Norway, explains, getting enough vitamin K from your diet is vital for redirecting this calcium. Yet most of us simply aren’t consuming anywhere near the volume of the right foods to benefit from it.

“Vitamin K is necessary for carrying calcium away from the heart and blood vessels into bone, thereby improving both heart and bone health,” says Aaseth. “The problem is that modern diets might contain two small amounts of vegetables [per day], for instance, broccoli, that contain vitamin K.”

It’s a relatively easy fix that can make a drastic difference to your long-term health. Consider one Spanish study that found people who increased their vitamin K intake had a 48 per cent lower risk of dying prematurely from cardiovascular disease. Making this change is all the more important for healthy ageing, as scientists believe that the majority of people in high-income countries such as the UK already have some degree of artery calcification by the time they turn 50.

But heart health is just one example of how consuming more of this remarkable micronutrient can improve your long-term wellbeing.

The importance of vitamin K

Our understanding of vitamin K’s importance for heart health is relatively recent. Although vitamin K was identified in 1929 by Danish scientist Henrik Dam, who later won the Nobel Prize for the discovery, it has long been associated primarily with blood clotting (hence the “K”, from the German koagulation). That narrow understanding is now shifting.

To begin with, vitamin K is really an umbrella term for a whole family of compounds found in a variety of foods [see below]. “The two main forms are vitamin K1 (phylloquinone) and vitamin K2 (menaquinones),” says Marc Sim, an associate professor at Edith Cowan University School of Medical and Health Sciences in Australia. “Vitamin K1 can also be converted into K2 by the body.”

Scientists are still trying to pin down the precise differences between vitamin K1 and K2, but K2 is thought to be better absorbed and circulate longer in the body, allowing it to reach different tissues. While K2 is thought to play more of a role in directing calcium into bones and away from arteries, K1 may play more of a role in blood clotting. However, researchers believe that both forms are important for our wider health, which is why many studies focus on overall vitamin K intake.

When we ingest vitamin K from our diet, it is used to activate a variety of proteins found throughout the body. Some are involved in blood clotting, some are involved in directing calcium into the bones, others are involved in brain health. Because of this, adequate vitamin K consumption has been linked with preventing everything from osteoarthritis to frailty. One study found that adults in their 60s and 70s who consume more vitamin K are not only cognitively sharper but also more physically capable – walking faster and rising from a chair with greater ease.

On the other hand, insufficient intake is increasingly being linked to different chronic diseases. “Low vitamin K intake leads to vascular calcification, cardiovascular disease, bone fractures, cognitive dysfunctionand not enough clotting,” warns Stefanos Roumeliotis, a kidney specialist at the Aristotle University of Thessaloniki in Greece. “Around 96 per cent of chronic kidney disease patients are very deficient in vitamin K.”

How can we get more of it in our diet?

I’ve been investigating vitamin K as part of The Age Code, my new book on the link between what we eat and how well we age. My research showed that the overarching reason so many people of all ages are deficient in vitamin K is because most of us don’t consume enough foods rich in this micronutrient.

Vitamin K1, for example, is found predominantly in leafy green vegetables such as spinach, kale, broccoli and lettuce. Meanwhile, vitamin K2 is typically found in eggs, and chicken livers and thighs. Because this micronutrient is present in cow’s milk, dairy products such as full-fat milk, yogurt, kefir, aged and hard cheeses such as gouda and edam, as well as soft and blue cheeses including brie, camembert and roquefort are all rich sources of vitamin K2.

“Cows consume K1 through grass and then convert it into K2 through their gastric bacteria,” says Roumeliotis.

Sim believes that low vitamin K intake often reflects poor dietary habits. “For example, people who simply aren’t consuming enough vegetables, or are predominantly consuming foods that are poor in micronutrients,” he says.

Instead, eating 1.5 cups of leafy green vegetables is thought to provide an adequate amount of vitamin K1, and a couple of scoops of Greek yogurt or slices of aged cheese will deliver vitamin K2.

Should we all take vitamin K supplements?

Given the importance of vitamin K for all aspects of health as we age, longevity experts have begun to wonder whether more people should be advised to take supplements as a way of getting higher doses into our bodies. “Although adequate diet is crucial, supplements might be necessary, especially after 60,” says Aaseth.

According to Jennifer Lees, a kidney specialist who has a PhD in vitamin K research from the University of Glasgow, it’s possible supplements may be beneficial, as vitamin K insufficiencies seem to become more prevalent with age. This may be linked to gut ageing, as a proportion of our vitamin K2 needs are created directly by microbes in our intestines. “The evidence we do have from relatively small trial populations suggests that as many as 97 per cent of older adults may have at least a mild vitamin K insufficiency,” says Lees.

Lees says it’s possible that taking a vitamin K2 supplement alongside the recommended daily dose of vitamin D could be beneficial, as vitamin D helps improve calcium absorption, while vitamin K directs it to the right places. However, she remains cautious, as scientists have yet to show that taking a K2 supplement over time can meaningfully improve someone’s health. “Supplementing low vitamin K levels with a tablet cannot provide the same wide-ranging benefits as following a diet rich in fresh fruits, vegetables and whole grains, which contains a range of other benefits beyond improving vitamin K intake,” says Lees.

Roumeliotis, however, is more bullish on the potential of vitamin K supplements to improve health, especially in the over-60s and individuals with existing kidney problems. “Right now, I’m running a big clinical trial where I’m giving 1,000 μcg of vitamin K2 (MK-7) each day to chronic kidney disease patients, under dialysis, and they are doing just fine,” he says.

For the rest of us, however, it is probably best to focus on getting more vitamin K from eating the right foods. “The priority should be improving overall diet quality, which will naturally provide adequate vitamin K alongside other nutrients important for cardiovascular health,” says Sim. “Leafy green vegetables and other whole foods provide a range of nutrients that work together to support cardiovascular, bone, muscle and cognitive health. Supplements can complement, but shouldn’t be used as a replacement for a balanced diet.”

[Source: Daily Telegraph]