Vitamin K: Support Healthy Bones & Blood Clotting
Vitamin K: Support Healthy Bones & Blood Clotting
Ever nicked yourself chopping ginger in the kitchen and noticed the bleeding stops within minutes? That's vitamin K working quietly behind the scenes. Most of us never think about this vitamin until a doctor mentions it — usually in the same breath as "blood thinners" — but it does far more than help wounds close up.
What Is Vitamin K?
Vitamin K isn't a single compound — it's a family of fat-soluble vitamins, meaning your body absorbs it best alongside dietary fat, similar to vitamins A, D, and E. Vitamin K is a fat-soluble vitamin that is naturally present in some foods, and it includes phylloquinone (vitamin K1) and a series of menaquinones (vitamin K2).
The main type, phylloquinone, is found in green leafy vegetables like collard greens, kale, and spinach. The other type, menaquinone, comes mostly from fermented foods and animal products — think the fermented soybean dish natto popular in Japan, certain cheeses, and to a smaller extent, chicken and eggs. Food sources of phylloquinone include vegetables, especially green leafy vegetables, vegetable oils, and some fruits, while meat, dairy foods, and eggs contain low levels of phylloquinone but modest amounts of menaquinones. Once absorbed, your body stores vitamin K in the liver and other tissues, including the brain, heart, pancreas, and bone.
Why Do People Take It?
Helps Your Blood Clot Properly
This is vitamin K's best-known job, and the reason it's sometimes called the "clotting vitamin." Vitamin K is known as the clotting vitamin because the body needs it to make certain proteins in the liver that cause blood to clot, and these proteins are called clotting factors. Without vitamin K, the liver could not produce clotting factors II, VII, IX, and X, and blood would not clot properly. This is why newborns in Singapore hospitals are routinely given a vitamin K shot shortly after birth — babies have only a small store of vitamin K at birth, which is quickly used up in the first few days of life, so a supplement may be given to prevent Vitamin K Deficiency Bleeding.
Supports Strong, Dense Bones
Beyond clotting, vitamin K plays a supporting role in skeletal health. It's an essential vitamin for bone health, taking part in the carboxylation of many bone-related proteins, regulating genetic transcription of osteoblastic markers, and regulating bone reabsorption. Some studies suggest that vitamin K helps maintain strong bones in older adults — relevant for Singapore's ageing population, where fracture risk climbs steadily after menopause and beyond age 60. Because adequate vitamin K intake is essential in maintaining bone health, nutrition experts generally recommend consuming at least a cup of dark green leafy vegetables daily.
May Support Heart and Artery Health
A newer area of research looks at vitamin K's role in keeping calcium in bones and out of blood vessels. Vitamin K2 helps regulate soft tissue calcification through activation of an anti-calcific protein called matrix Gla protein, and studies show a strong association between vitamin K deficiency and arterial stiffness, vascular calcification, and cardiovascular mortality. This matters in the SEA context, where cardiovascular disease remains a leading cause of death and where PMEB professionals juggling long hours often deprioritise the leafy, less-convenient side of their meals. That said, clinical trial results on supplementation are still mixed, so this is an emerging benefit rather than a settled one.
Works Alongside Vitamin D for Calcium Balance
Vitamin K and vitamin D are often discussed as a pair because they influence calcium in complementary ways — vitamin D helps you absorb calcium from food, while vitamin K helps direct that calcium to where it belongs, in bones rather than soft tissue. Getting both consistently, rather than just one, appears more relevant to long-term bone and vascular health than focusing on either alone.
Bioavailability & Absorption
Because vitamin K is fat-soluble, it needs some dietary fat present to be absorbed efficiently from your gut — a plate of steamed kailan eaten completely dry absorbs less vitamin K than the same vegetable stir-fried in a little oil. This is actually a point in favour of local cooking styles: many Singaporean and Malaysian vegetable dishes are already stir-fried with oil or garlic, which naturally helps absorption.
Gut bacteria in the large intestine also produce some menaquinone, though how much of this the body actually uses is still debated among researchers. Certain medications interfere with absorption or function — taking vitamin K by mouth should be spaced at least two hours apart from orlistat, a weight-management medicine, to prevent reduced vitamin K absorption. Long-term use of certain antibiotics can also lower vitamin K levels by disrupting the gut bacteria that help produce it.
Safety Basics
Vitamin K from food is considered very safe, and there's no established upper limit because toxicity from diet alone is essentially unheard of. The real caution point is drug interactions rather than the vitamin itself. If you're taking a blood thinner such as warfarin, it's very important to get about the same amount of vitamin K each day, rather than swinging between very high and very low intakes — sudden changes, like starting a big salad habit or suddenly cutting out greens, can throw off how well the medication works. This is a genuine local concern, since many older Singaporeans and Malaysians on warfarin for heart conditions may not realise their usual bowl of kailan or spinach soup affects their treatment.
People with liver disease should also be mindful, since the liver is where vitamin K–dependent clotting proteins are made. As with most nutrients, the sensible approach is consistency rather than extremes — this isn't a vitamin to suddenly load up on or avoid without medical guidance, especially if you're on anticoagulants.
Natural Food Sources
- Kailan, chye sim, and spinach — common in stir-fries and soups across SEA kitchens
- Kale, broccoli, and Brussels sprouts — increasingly available in local supermarkets
- Cabbage and lettuce, often eaten raw in salads or as ulam
- Natto and other fermented soybean products, rich in menaquinone
- Certain cheeses, which contain modest amounts of menaquinone
- Vegetable oils such as olive, canola, and soybean oil used in everyday cooking
- Eggs and chicken, in smaller but still useful amounts
Worth noting: a typical breakfast of nasi lemak or a lunch of chicken rice and ban mian tends to be heavy on refined carbohydrates and light on the leafy vegetables that actually carry vitamin K — something to be mindful of if most of your meals lean that way.
Related Articles
Explore Related Nutrients
Final Thoughts
Vitamin K rarely gets the spotlight that calcium or vitamin D enjoys, but it's doing essential work underneath the surface — helping wounds close, and quietly supporting bones and blood vessels over the decades. The reassuring part is that it doesn't require anything exotic: a regular helping of stir-fried leafy greens, done the way most SEA kitchens already cook them, goes a long way. The one group who genuinely needs to pay attention are those on blood-thinning medication, where consistency in vitamin K intake matters more than quantity. For everyone else, the habit of "tahan-ing" through a diet mostly of refined carbs and skipping the vegetables is really the bigger risk worth addressing.
This article is for general informational purposes and is not a substitute for professional medical advice. Please consult a qualified healthcare professional before making any changes to your diet or supplement routine.
References
- NIH Office of Dietary Supplements
https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/ - Harvard T.H. Chan School of Public Health
https://nutritionsource.hsph.harvard.edu/vitamin-k/ - MedlinePlus
https://medlineplus.gov/ency/article/002407.htm - Linus Pauling Institute
https://lpi.oregonstate.edu/mic/vitamins/vitamin-K - 🇸🇬 SGHealthHub Singapore
https://www.healthhub.sg/medication-devices-and-treatment/medications/vitamin-k - PubMed Central
https://pmc.ncbi.nlm.nih.gov/articles/PMC6955144/