What is vitamin K and is it good for me?

A beginner's guide to vitamin K – and why it can be the key to anti-ageing

Romanesco broccoli - Vitamin K
Romanesco broccoli - Vitamin K

A beginner's guide to vitamin K – and why it can be the key to anti-ageing

By Sophie Williams20 Feb 2023
6 mins read time
6 mins read time

Chances are, vitamin K hasn’t always been on your radar. If we were to guess, the more famous ones like C and D are more likely to be topics of conversation. Like, "what vitamins should I take to stop me getting sick?" Or “I can’t wait for that sunshine vitamin glow when I go on holiday.”

Of course, these trusty ones have their own explainers (that goes without saying), and we’re presuming you’ve probably already read them. So, we thought it was about time we highlight another vitamin (or a group, should we say) that should be part of your daily dose, too.

We spoke to Nina Prisk, leading aesthetics nurse and GPhC-accredited independent prescriber about all things vitamin K, including its benefits, sources, and how to recognise a deficiency.

What is Vitamin K?

“Vitamin K is a group of vitamins that help the blood to clot and wounds to heal. It also may help to keep bones healthy,” Nina says.

A Harvard article documenting all things vitamin K backed these claims up too, specifically touching on two proteins that help with said clotting and healing.

“Prothrombin is a vitamin K-dependent protein directly involved with blood clotting,” it reads. “Osteocalcin is another protein that requires vitamin K to produce healthy bone tissue.”

According to the piece, vitamin K is found in multiple parts of the body, “including the liver, brain, heart, pancreas, and bone.” These areas are able to break it down very quickly, often excreting the vitamin via the urine or stool. (Poo, to be more informal.)

“Because of this, it rarely reaches toxic levels in the body even with high intakes, as may sometimes occur with other fat-soluble vitamins,” it adds.

Vitamin K benefits

In addition to the blood clot and wound healing benefits, Nina says that it’s also believed that vitamin K can be hugely valuable to the skin. OK, we’re listening.

“This is because of its anti-inflammatory properties that help to reduce bruises and improve the skin’s ability to heal wounds,” Prisk explains.

She also adds that the vitamin group can address free radical damage (unstable atoms that can compromise cells, causing illness and ageing), and help to prevent the breakdown of collagen. Plus, it can effectively combat premature skin ageing, “helping to leave skin smooth and plump.”

It’s not just skin and bone that vitamin K can help with, either. Medical News Today has also reported its cognitive and heart health benefits. In terms of the former, it has been found that increased blood levels of the vitamin have been “linked with improved episodic memory in older adults.”

They backed this up by a study in which a group of healthy adults with high vitamin K1 blood levels over the age of 70 had “the highest verbal episodic memory performance.”

And the heart health, you ask? Apparently, it helps to lower blood pressure “by preventing mineralisation, where minerals build up in the arteries.” This basically means the heart can “pump blood freely through the body,” with the piece explaining that mineralisation is a symptom that “naturally occurs with age.”

Adding that it’s a “major risk factor for heart disease,” the article explains that a good amount of vitamin K can help to “lower the risk of stroke.”

Vitamin K deficiency

“There are a number of symptoms that can be associated with vitamin K deficiency,” Nina says.

“This includes skin that bruises easily, heavy periods, more bleeding than usual from wounds, and blood in the urine and/or stools.”

Excessive bleeding is the main culprit when lacking this vitamin, and it can manifest itself in different ways depending on your body type. For example, you may experience bleeding in places other than traditional wound sites, including:

  • Small blood clots underneath the nails
  • Bleeds in mucous membranes that line the areas inside the body (as per Healthline)

Vitamin K sources

So, you’re looking to incorporate more of this vitamin group into your diet and daily lifestyle? Vitamin K1 (or otherwise known as phylloquinone) is the most common form of it, and it can be found in plants. Most notably dark, green leafy vegetables - think kale, rocket, spinach, bok choy, collards, mustard greens, etc.

Once you ingest these foods, bacteria in the large intestine converts it into its storage form - menaquinone, a lesser source of vitamin K (vitmain K2). It’s then absorbed by the small intestine and stored in the liver and fatty tissues.

According to Prisk, if you want to incorporate the food source of vitamin K2 into your meal plans, it can only be found in “animal-sourced foods and fermented plants, such as cheese, chicken, butter and egg yolks.”

Top tip: due to vitamin K being fat-soluble, it’s recommended you eat foods high in it alongside healthy fats to improve the absorption. Whether you add some IG-ready avo to your leafy salad or you drizzle over some olive oil, you’ll help your body to retain as much as possible.

Heads up though - if you’re taking antibiotic medicines, note that it may destroy the bacteria in the gut that produces vitamin K. This will obviously reduce the levels in the body, especially if you’re on the medication indefinitely, or for more than a few weeks.

Plus, those who combine long-term antibiotic use with a poor diet (i.e ignore the healthy foods high in the vitamin), chances are, a vitamin K supplement will be necessary.

How long does it take to recover from vitamin K deficiency?

Once you address your vitamin K deficiency, it won’t take long until your body responds and is back to normal.

“It can be treated with either oral supplements or injections,” Prisk says, but adds that more long-term solutions may be necessary for people with underlying chronic conditions.

Alongside regularly eating the healthy foods we mentioned previously, “it’s believed that the effects of Vitamin K supplements usually take between two and five days,” she concludes.

How much vitamin K should I take per day?

According to the NHS, “adults need approximately 1 microgram of Vitamin K for each kilogram of their body weight.” Though most people should be able to get all the Vitamin K they need through following a healthy and varied diet. Nina adds that “any excess vitamin K your body doesn’t immediately need is stored in the liver for future use, so this allows for the fact that you may not be getting it from your diet every day.”

The bottom line? While vitamin K might not be the bonniest vitamin in the crown, (we’re referencing that poo talk from earlier) it’s still completely necessary for a healthy and balanced lifestyle.