15% off €35


15% off €35



Buy 1 Get 1 Half PriceSummer ShopOffersOffers HubBuy One Get One 1/2 PriceOnline only 25% off or moreSave up to 1/2 priceGreat SavingsOutletBuy 1 Get 1 FreeBetter than 1/2 priceBuy 2 for €23 Mix & Match3 for 2 Mix & MatchShort Dated1/2 PriceVitamins & SupplementsVitamins & Supplements HubJoints, Aches & PainsGut HealthImmunityEnergyChildren's HealthHealthy HeartWeight ManagementExercise & RecoveryLow Mood & DepressionStress & AnxietyVitamins & Supplements Shop AllCBDCollagen & SilicaHair, Skin & NailsShop all Hair, Skin & NailsHair GrowthFunctional MushroomsVitaminsShop all VitaminsMultivitaminsVitamin AVitamin BVitamin CVitamin DVitamin EVitamin KVitamin DrinksMineralsShop all MineralsMagnesiumIronZincCalciumSeleniumChromiumSupplementsShop all SupplementsFibre SupplementsAcidophilus & Friendly BacteriaPeppermint OilGrapeseed ExtractLecithinCollagen & SilicaOmega & Fish OilsPlant Sourced SupplementsSuperfood SupplementsArnicaApple CiderRaspberry KetonesAloe VeraChondroitin & MSMCo Enzyme Q10Evening Primrose OilGarlicGlucosamineGlucomannanSeaweed, Kelps and AquaceuticalsDigestive EnzymesSaw palmettoCharcoalWomen's HealthShop all Women's HealthMenopauseMenstrual SupportUrinary Tract HealthPregnancy & ConceptionMen's HealthShop all Men's HealthProstate HealthChildren's HealthConditionShop all ConditionCholesterolAllergy & Hay Fever CareAnxiety SupportBone & Muscle HealthMuscle Support & Joint PainBrain & Memory SupportWomen's HealthMen's HealthChildren's HealthCold & Immune SupportFatigueDigestive HealthHair, Skin & NailsHeart & CirculationLiver CareMood SupportSexual HealthSleep & RelaxationStress ReliefVisionHerbal & Licensed RemediesShop all Herbal & Licensed RemediesValerianRescue RemedyAshwagandhaMilk ThistleGinseng & GuaranaHomeopathic & Flower RemediesShop all Homeopathic & Flower RemediesRescue RemedyFlower RemediesVegan Vitamins & SupplementsBuy One Get One 1/2 PriceOnline only 25% off or moreSave up to 1/2 priceHolland & BarrettVitabioticsSolgarNew NordicBetterYouBioglanNatures AidPE NutritionGrass & Co.H&B ExpertDairy FreeGluten FreeSesame Seed FreeCelery FreeCereal FreeCrustaceans FreeEgg FreeFish FreeKiwi FreeLupin FreeNew inFood & DrinkFood & Drink HubImmunityExercise & RecoveryGut HealthEnergyJoints, Aches & PainsDental HealthWeight ManagementFood & Drink Shop AllVegan FoodDried Fruit, Nuts & SeedsShop all Dried Fruit, Nuts & SeedsDried FruitNutsSeedsMixesHoney, Jams & SpreadsShop all Honey, Jams & SpreadsManuka HoneyHoneyJams & ChutneysNut ButtersSpreadsPateSuperfoodsShop all SuperfoodsSuperfood PowdersMoringa PowderSpirulinaGoji BerriesBaobabChia SeedsDrinks & JuicesShop all Drinks & JuicesKombuchaNatural Energy DrinksJuicesSoft DrinksWaterAlcohol Free DrinksTeas, Coffee & Hot BeveragesShop all Teas, Coffee & Hot BeveragesCoffee & Coffee SubstituteMushroom DrinksTeaSuperfood TeaMatcha & Green TeaSleep & Relaxation TeaSnacksShop all SnacksProtein BarsLow Calorie SnacksChocolate, Cakes & BiscuitsSavoury SnacksSweet SnacksSnack BarsCrisps & ChipsFlapjacksPopcornFood CupboardShop all Food CupboardCondiments & SaucesApple Cider VinegarSuperfoodsBreakfast CerealsHoney, Jams & SpreadsTinned FoodsRice, Pasta, Pulses & GrainsBreakfast CerealsShop all Breakfast CerealsCereals, Bran & FlakesGranolaMuesliOats & PorridgeBreakfast BarsCookingShop all CookingCooking IngredientsApple Cider VinegarCondiments & SaucesSoya & Meat AlternativeSoup & Ready MealsRice, Pasta, Pulses & GrainsHerbs, Spices & SeasoningGravy & StockHome BakingShop all Home BakingBaking MixesBreadFlourSweeteners & Sugar AlternativesEgg SubstitutesDairy AlternativesShop all Dairy AlternativesOat, Rice & Hemp DrinksSoya DrinksNut DrinksCoconut DrinksNutritionally Complete FoodBuy One Get One 1/2 PriceSave up to 1/2 priceOnline only 25% off or moreHolland & BarrettGrenadeNaturyaPukkaPhDHeath & HeatherHuelMeridianNakdTwiningsGluten FreeDairy FreeWheat FreeEgg FreeSugar FreeMilk FreeSoya FreeSesame Seed FreeCelery FreeFish FreeNew inSports NutritionSports Nutrition HubExercise & RecoveryEnergyWeight ManagementSports Nutrition Shop AllProteinShop all ProteinClear ProteinProtein VeganMeal ReplacementsWhey ProteinMass GainersDiet ProteinCaseinSports SupplementsShop all Sports SupplementsTestosteroneSports CollagenBars, Drinks & SnacksShop all Bars, Drinks & SnacksEnergy BarsProtein BarsProtein ShakesProtein SnacksNutritionally Complete FoodMeal Replacement ShakesPre Workout & EnergyShop all Pre Workout & EnergyPre WorkoutAmino Energy DrinksAmino Energy PowdersIntra WorkoutKetoPost WorkoutAmino AcidsShop all Amino AcidsBCAAL-LysineGlutamineArginineCreatineShop all CreatineCreatine PowderRehydrationShop all RehydrationElectrolytesEnergy GelsVegan Sports NutritionShop all Vegan Sports NutritionVegan ProteinVegan Protein BarsVegan Pre Workout & EnergyVegan Amino AcidsVegan CreatineSports AccessoriesShop all Sports AccessoriesBottles & ShakersFitness GoalShop all Fitness GoalRecoveryMuscle & StrengthLean MuscleEnergy & EnduranceDiet & Weight LossKetoSave up to 1/2 priceGreat SavingsBuy One Get One 1/2 PricePE NutritionOptimum NutritionGrenadeUSNPhDApplied NutritionHuelFoodspringSiSYfoodGluten FreeDairy FreeSugar FreeSoya FreeCelery FreeCereal FreeCrustaceans FreeEgg FreeFish FreeKiwi FreeNew inBeautyBeauty HubSkin Health - by skin concernDental HealthWomen's Health - Cycles & MenstruationSexual HealthWomen's Health - PregnancyChildren's HealthExercise & RecoveryJoints, Aches & PainsHealthy HeartImmunityNatural Beauty Shop AllAromatherapy & HomeShop all Aromatherapy & HomePure Essential OilsBlended Essential OilsBase & Carrier OilsHolisticSkincareShop all SkincarePremium SkincareFace CareBody CareSun CareTanning & BronzingEye CareLip CareFoot CareHand & Nail CareCBD BeautyHair Skin & NailsShop all Hair Skin & NailsNail ConditionsSkin ConditionsCollagenWashing & BathingShop all Washing & BathingShampoo & ConditionerBathing AccessoriesShower Gel & Body WashDeodorantDentalHand WashSoapBath Soak & OilBody ScrubBath Bombs & SaltsFeminine CareIncontinence SupportHair CareShop all Hair CareShampoo & ConditionerHair ColouringHair MasksHair Oil & SerumHair Spray, Gel & MousseHair AccessoriesMother & BabyShop all Mother & BabyBaby Skincare & ToiletriesMakeupElectrical WellnessSexual WellnessBuy One Get One 1/2 PriceOnline only 25% off or moreSave up to 1/2 priceDr OrganicFaith in NatureWeledaNaturtintTisserandMiaromaQ+AEthiqueTrilogyChilds FarmAlcohol FreePalm Oil FreeParfum FreeParaben FreeSLS FreeMicroplastics FreeCelery FreeCereal FreeCrustaceans FreeDairy FreeNew inWeight ManagementWeight Management HubExercise & RecoveryWeight ManagementEnergyHealthy HeartWeight Management Shop AllSlimming TabletsFat Burners, Binders & Appetite SuppressantsShop all Fat Burners, Binders & Appetite SuppressantsFat BurnersFat BindersAppetite SuppressantsShakes & Weight Management ShotsShop all Shakes & Weight Management ShotsMeal Replacement ShakesWeight Management ShotsDiet Food & DrinkShop all Diet Food & DrinkDiet FoodLow Calorie SnacksSlimming TeaExercise SupportBuy One Get One 1/2 PriceSave up to 1/2 priceGreat SavingsGrenadeOptimum NutritionHolland & BarrettPhDPulsinEat WaterUSNNatures AidSlimExpertApplied NutritionSugar FreeGluten FreeDairy FreeWheat FreeNew inHealth & WellnessShop all Health & WellnessGut HealthSkin Health - by skin concernEnergyWomen's Health - Hormonal HealthJoints, Aches & PainsWomen's Health - Menopause & PerimenopauseExercise & RecoveryImmunitySleep & RelaxationChildren's HealthJoints Bones & MusclesGut HealthShop all Gut HealthGut Health FoodGut Health SkincareHair Skin & NailsShop all Hair Skin & NailsNail ConditionsSkin ConditionsCollagenStress AnxietyShop all Stress AnxietyEnergy SupportSleep & RelaxationShop all Sleep & RelaxationRelaxationFood & DietShop all Food & DietKeto FoodMenopauseBuy One Get One 1/2 PriceOnline only 25% off or moreSave up to 1/2 priceHolland & BarrettNaturtintDr OrganicVitabioticsWeledaSolgarNew NordicEthiqueWildNatures AidDairy FreeGluten FreeSugar FreeAlcohol FreeWheat FreeSesame Seed FreeSoya FreeCelery FreeCereal FreeCrustaceans FreeNew inShop for your WellnessJoints, Bones & MusclesWomen's HealthMenopauseSkincareGut HealthHair, Skin & NailsImmunitySleep & RelaxationFood & DietChildren's HealthStress ReliefHealthy HeartEnergyLow Mood & DepressionEye HealthSexual HealthLearn about WellnessJoints, Bones & MusclesWomen's HealthPeriod & Cycle HealthMenopauseImmunityGut HealthFood & DietSports & FitnessSleep & RelaxationHair Skin & NailsArticlesAll articlesHealthFood & nutritionGut healthImmunityJoints, bones & musclesWomen's healthWellnessHair & skinMental wellbeingSeasonalSleep & relaxationSports nutritionRecipesAll recipesGluten freeLow sugarVeganDairy freePodcast

What is vitamin K2?

white vitamin K tablets on wooden spoon

Most of us have heard of Vitamins C and D, as well as many others. But what about Vitamin K2, how familiar are you with that one?

This particular vitamin isn’t one of the more-talked-about vitamins, but that doesn’t make the role it has on the human body any less important.

Over the next few paragraphs, we’re going to talk you through Vitamin K2, as well as answer these commonly-asked questions:

  • What is Vitamin K2 good for?
  • Which foods are high in Vitamin K2?
  • Is too much Vitamin K2 bad for you?

What is Vitamin K?

Before we talk about Vitamin K2, it’s important we briefly introduce you to its main counterpart, Vitamin K, which isn’t just one standalone vitamin.

Vitamin K is responsible for making sure our blood clots properly by producing proteins that enable this to happen. Without Vitamin K in our system, our blood would take a very long time to clot and wounds potentially may not heal properly. It’s also believed Vitamin K can help with bone health among older people.1

Vitamin K is measured in micrograms and the amount we need in our bodies varies depending on how old we are.2

Daily recommended Vitamin K intake

Age Amount (a day)

Birth - 6 months

2.0 micrograms

7 - 12 months 2.5 micrograms
1 - 3 years 30 micrograms
4 - 8 years 55 micrograms
9 - 13 years 60 micrograms
14 - 18 years 75 micrograms
Adult men (19 and over) 120 micrograms
Adult women (19 and over)  90 micrograms
Pregnant or breastfeeding teens 75 micrograms
Pregnant or breastfeeding women 90 micrograms



 Vitamin K plays a key role in blood clotting and wound healing, as well as good bone health among older adults. The recommended daily intake of Vitamin K ranges from 2 micrograms to 120 micrograms, depending on how old you are.

Which foods are high in Vitamin K2?

Like most vitamins, Vitamin K is present in certain food. Overall, the NHS says that Vitamin K’s mainly present in green leafy veg, vegetable oils, cereal grains and a small selection of meat and dairy food.3

Here are some further examples of Vitamin K food sources4:

Food Vitamin K content (in micrograms)
1/2 cup of kale 225
1/2 cup of raw spinach  75
1/2 cup of turnip greens 70
1/2 cup of broccoli 45
1/2 cup of cabbage 30
1 tbsp of soybean oil 25
1 cup of iceberg lettuce 14
1 cup of strawberries 4
1 cup of whole milk 1
1 large egg <1

For more Vitamin K food examples, check out this article, ‘30+ Vitamin K foods.’


Green leafy veg, vegetable oils and cereal grains, as well as a whole host of even more food sources, all contain Vitamin K. There’s also a group of foods that are considered as being particularly high in Vitamin K2 (see below).

What is Vitamin K2?

Vitamin K2 is one of the vitamins that sits within the overall Vitamin K group.

Vitamin K exists in two main forms:

Type 1: Vitamin K1, also known as phylloquinone

This form of Vitamin K is mainly found in plant foods, e.g. those listed above.

Type 2: Vitamin K2, also known as menaquinone

This form is present in animal and fermented foods. A small amount of it’s also produced naturally by human gut bacteria by turning Vitamin K1 into Vitamin K2.

In addition to Vitamin K1 and Vitamin K2, there are lots of Vitamin K2 sub-groups that have been named, depending on the length of their side chain. They range from MK-4, right up to MK-13.5

MK-4 is present in some animal products and is the only form of Vitamin K2 that isn’t produced by bacteria. Examples of MK-4 include egg yolks and butter.

Meanwhile, MK-5 up to MK-15 have longer side chains, are produced by bacteria and are often present in fermented foods. For instance, Natto, is made from fermented soybeans and is high in MK-7.


Vitamin K2, which is also known as menaquinone, is present in both animal and fermented foods. A small amount of it is also produced naturally by human gut bacteria by turning Vitamin K1 into Vitamin K2.

What is Vitamin K2 good for?

Vitamin K2 has two specific roles within the human body that relate to our bones and blood vessels.6

1. Within our blood vessels – it activates a protein called Matrix Gla-protein, which is responsible for removing calcium from the lining of blood vessels. This is important for heart health, as calcification of blood vessels is a risk factor for heart disease.

2. Within our bones - it activates osteocalcin, a bone-forming protein. It is an important nutrient for bone health because it helps our bones draw calcium from our blood vessels and turn it into bone tissue.

Vitamin K2 reportedly has more widespread benefits than its other Vitamin K counterparts, particularly Vitamin K1. One of the main benefits is that it can stay stored in the liver for up to 72 hours, compared to Vitamin K1, which usually leaves the liver within eight hours.7

Other Vitamin K2 benefits include:

  • Vitamin K2  is good for heart health

 Vitamin K2 helps to direct calcium to the bones and prevent it from being deposited where it shouldn't be, for example arteries and organs, where it can cause harm.8 According to The Rotterdam Study research, in which men were studied for more than 15 years, the highest intake of Vitamin K2 was linked with a lower risk of heart-related issues, including cardiovascular disease, and cardiovascular disease mortality.9

  • It’s good for bone health

Vitamin K3 activates the proteins that help regulate calcium deposition. This means that it supports the calcification of bones and prevents calcium deposits from forming in the blood vessels.10 A study of Japanese postmenopausal women, who ate Natto, found that they experienced lower bone loss over time.11

  • And dental health too

Due to the fact the protein that’s needed to build strong teeth, osteocalcin, is the same one activated by Vitamin K2 to regulate bone calcification. However, it’s important to flag here that research in relation to this particular benefit is limited at present.12 (For more information about the fundamentals of dental health, have a read of this, ‘Calcium and dental health.’)


 Several health benefits have been linked to Vitamin K2. They range from helping prevent heart disease and maintaining healthy bones, to building strong teeth.

How can I get Vitamin K2 naturally?

Quite simply, by eating more Vitamin K2-rich food.

But here’s the thing, while guidance on daily Vitamin K supplements currently exists (as set out above) and the NHS says adults need around 1 microgram (mcg) a day of Vitamin K for each kilogram of their body weight, there’s no guidance in relation to daily Vitamin K2 intake levels at present.

It may be that you introduce just one or two Vitamin K2 foods to your daily diet, or you opt for several different things. Of all the food sources, these contain the highest levels of K2:

Vitamin K2 foods

1. Natto (fermented soy)

Natto happens to have extremely high Vitamin K2 levels. It reportedly contains around 15 times more Vitamin K2 than the best hard cheese sources and 200 times more than the fermented cabbage dish, sauerkraut.13

2. Dark meat

For example, the darker parts of chicken, such as the leg or the thigh.

3. Fermented cheeses 

Cheese like Edam, Gouda or cheddar and blue cheese all contain lots of Vitamin K2 that’s been created by bacteria during the production process.

4. Egg yolks

Poached or hard boiled, however you have them, egg yolks in particular are a good source of Vitamin K2.14

Note – Milk and butter that’s produced by grass-fed cows reportedly contains more Vitamin K2 than milk and butter that’s produced by cows that eat grains. The level of Vitamin K2 in cheese depends on what’s produced by the cheese cultures.15


 It’s possible to boost Vitamin K2 levels naturally by eating lots of Vitamin K2 foods. You may want to eat them in moderation though because there’s currently no guidance on daily intake levels for Vitamin K2.

Is too much Vitamin K2 bad for you?

While evidence of the impact of having too much Vitamin K in our systems remains limited right now, it’s still important you make sure you don’t exceed the recommended daily intake levels.

The NHS says it’s important, and possible, to get sufficient quantities of Vitamin K by eating a healthy and balanced diet that contains food sources, such as those listed above.17

Being deficient in Vitamin K is a rare thing, but if your levels are depleted, then it is possible to take a supplement to help increase them. Vitamin K is also available in supplements that contain just  Vitamin K or Vitamin K combined with other nutrients, such as calcium, magnesium, and/or vitamin D.18

The most common types of Vitamin K supplements are:

1. Phylloquinone and phytonadione (AKA Vitamin K1)

2. Menaquinone-4, and menaquinone-7 (AKA Vitamin K2).


It’s not yet clear what too much Vitamin K2 can do to the body; more research is required to clarify the consequences. If you are low in Vitamin K2, you should be able to raise your levels by eating Vitamin K2 foods or by taking a supplement.

A final few words about Vitamin K2

When it comes to making sure our bodies function properly, Vitamin K2 is incredibly important. Without it, our blood wouldn’t clot, our bones wouldn’t develop as they should, or stay healthy and strong, and any wounds would heal with great difficulty. Vitamin K2 is right up there in terms of making sure some of the fundamental workings of the human body take place.

While Vitamin K2 isn’t one of the more common vitamins to be lacking in, deficiencies can occur. Vitamin K2 levels can be increased either by eating Vitamin K2 foods or taking supplements. If you are planning on doing the latter, check with your GP first before you do so to identify the cause of your deficiency and make sure you’re taking the right amount of Vitamin K2 for you.

For more information about Vitamin K, particularly in relation to babies, check out this article, ‘Vitamin K for babies.’

Last updated: 5 March 2021

Related Articles

  • Visa
  • MasterCard
  • AmericanExpress
  • PayPal
  • Facebook
  • Twitter
Copyright © Holland & Barrett Limited, 2024. All rights reserved. hollandandbarrett.ie is a trading name of Holland & Barrett Limited. Registered office: 45 Henry Street, Dublin, Dublin 1, D01 E9X8. Registered in Ireland: Company no. 79819. Registered VAT no. 4682002U.