A single cup of cooked kale delivers more than 900% of your daily vitamin K requirement, making leafy greens the most concentrated source of this essential nutrient. Vitamin K refers to a group of fat-soluble compounds your body uses to stop bleeding and to keep bones and arteries from quietly breaking down. Two distinct forms matter most: phylloquinone (K1) from leafy greens drives blood clotting, while menaquinone (K2) from fermented foods and animal products directs calcium into bones and away from artery walls.
Below, you’ll find exact microgram counts for top foods, daily targets for men and women, and safety guidance for adults, infants, and anyone on blood thinners.
The Two Forms of Vitamin K and Why Both Matter
Vitamin K1, called phylloquinone, lives in green plants and travels straight to the liver, where it activates clotting factors II, VII, IX, and X. Without enough K1, even a small cut can ooze far longer than it should, and a bruise can spread like spilled ink under the skin. The NIH Office of Dietary Supplements frames K1’s role almost entirely around coagulation, because that is where deficiency shows up first and most dramatically.
Vitamin K2, called menaquinone, behaves differently. It activates proteins called osteocalcin and matrix Gla-protein, which pull calcium into bone and keep it from depositing in arterial walls. K2 exists in several subtypes (MK-4 through MK-10), each with a different half-life and food source. MK-4 comes mainly from animal products, MK-7 from fermented foods, and the longer-chain forms from specific bacterial cultures.
Why the “Leafy Greens Only” Story Falls Short
Greens alone cannot cover K2. A salad-heavy pattern clears the clotting requirement but does little for the bone and vascular roles that the Rotterdam Study and the Heidelberg cohort both linked to K2 intake. Optimizing for K1 by eating spinach every day leaves K2 untouched unless fermented foods, eggs, poultry, or supplements enter the picture. Dietary patterns, not single nutrients, decide which form you actually absorb.
K1 Powerhouses: Ranking Leafy Greens by Real Microgram Amounts
Cooked spinach leads the pack with roughly 889 micrograms per cup, more than any other commonly eaten food. Cooked collard greens follow at about 770 micrograms per cup, then cooked kale at around 443 micrograms per cup. Swiss chard rounds out the top tier at roughly 300 micrograms per cooked cup. Cooking concentrates the vitamin by shrinking the food, so a cup of cooked greens delivers several times what the same vegetables offer raw.
| Food | Serving Size | Approximate K1 (mcg) |
|---|---|---|
| Cooked spinach | 1 cup | ~889 |
| Cooked collard greens | 1 cup | ~770 |
| Cooked kale | 1 cup | ~443 |
| Cooked Swiss chard | 1 cup | ~300 |
| Cooked broccoli | 1 cup | ~220 |
| Cooked Brussels sprouts | 1 cup | ~219 |
| Raw romaine | 1 cup, shredded | ~58 |
| Fresh parsley | 1/4 cup | ~246 |
Secondary Sources That Round Out the Day
Broccoli, Brussels sprouts, green beans, asparagus, and romaine all contribute meaningful amounts, especially when eaten across multiple meals. Fresh herbs like parsley and basil carry surprisingly high K1 per gram, so a tablespoon of chopped parsley adds up faster than its small size suggests. Plant oils such as soybean and canola, plus small portions of kiwifruit and blueberries, add modest amounts that help close the daily gap without changing the meal’s character.
The Fat-Pairing Rule
K1 absorbs only when dietary fat is present. A spinach salad dressed with olive oil, an avocado on the side, or a handful of nuts alongside cooked greens raises absorption substantially. Eating dry greens on their own wastes much of the vitamin. Fat-soluble vitamins travel through the lymphatic system rather than dissolving in water, so a meal without fat is a meal without usable K.
K2 Sources Most Articles Overlook, From Natto to Egg Yolks
Natto, the sticky fermented soybean dish common in Japan, delivers over 1,000 micrograms of K2 per serving as MK-7, roughly ten times more than any other common food. A two-tablespoon portion clears the daily requirement in a single spoonful. Few Western palates enjoy natto’s strong ammonia-like aroma, but small amounts stirred into rice or scrambled with eggs add the K2 without dominating the dish.
| Food | K2 Form | Serving Size | Approximate K2 (mcg) |
|---|---|---|---|
| Natto | MK-7 | 2 tablespoons | ~1,000+ |
| Hard cheeses (Gouda, Edam) | MK-7, MK-9 | 1 ounce | ~5–10 |
| Soft cheeses (Brie) | MK-9 | 1 ounce | ~4–7 |
| Chicken (thigh with skin) | MK-4 | 3.5 ounces | ~10–13 |
| Egg yolk | MK-4 | 1 large yolk | ~15–32 |
| Butter | MK-4 | 1 tablespoon | ~2–7 |
| Sauerkraut | MK-7, MK-9 | 1/2 cup | ~2–5 |
K2 Across Dietary Patterns
An omnivore eating chicken, eggs, and cheese typically pulls in 50–100 micrograms of K2 daily without thinking about it, mostly as MK-4. A lacto-ovo vegetarian relying on dairy and eggs lands in a similar range. A strict vegan skipping natto and fermented foods often falls below 20 micrograms per day, the gap that drives most of the interest in K2 supplements.
Gut bacteria do produce some K2, but the amounts and subtypes vary wildly between individuals and cannot be counted on as a reliable source. Probiotics may shift the picture over time, yet no clinical guideline treats gut production as a substitute for food or supplements.
Setting Your Daily Target and Hitting It Without Thinking About It
The adult Adequate Intake is 120 micrograms per day for men and 90 micrograms for women, set by the Institute of Medicine with coagulation as the primary endpoint. Real-world intake in the United States averages 200–400 micrograms of K1 daily, mostly from vegetable oils and greens, but K2 intake often sits below 30 micrograms per day, especially among adults who avoid fermented foods.
A Realistic Day on a Plate
A spinach omelet (two eggs plus one cup of cooked spinach) opens the day with around 900 micrograms of K1 and a dose of MK-4 from the yolks. A kale Caesar at lunch adds another 400-plus micrograms. Steamed broccoli at dinner pushes the K1 total well over 1,500 micrograms before snacks or oils count, more than ten times the minimum. K2 enters whenever a hard cheese, chicken thigh, or pat of butter joins the plate.
One-Week Patterns by Diet Type
- Omnivore plan: Eggs or chicken daily, one ounce of hard cheese three times a week, butter or ghee for cooking, plus leafy greens at two meals.
- Lacto-ovo vegetarian plan: Dairy and eggs at most meals, aged cheeses twice weekly, natto or sauerkraut as an adventurous add-on, leafy greens at lunch and dinner.
- Vegan plan: Natto two to three times weekly if tolerated, sauerkraut or kimchi daily, tempeh and other fermented soy products, plus leafy greens with every lunch.
- Limited-diet plan: If fermented foods are off the table, a daily MK-7 supplement at 100 to 200 micrograms fills the gap without dietary stress.
Who Falls Short
Newborns arrive with almost no vitamin K stored and breast milk supplies only trace amounts, which is why hemorrhagic disease of the newborn can strike within weeks of birth. Adults with fat malabsorption from celiac disease, Crohn’s, ulcerative colitis, or post-bariatric surgery also struggle, because the gut cannot absorb fat-soluble vitamins even when intake looks fine on paper. Long-term broad-spectrum antibiotics wipe out the gut bacteria that contribute small amounts of K2, adding another quiet shortfall.
When Supplements Make Sense and Which Form to Actually Buy
Most healthy adults eating a varied diet with daily greens do not need a vitamin K supplement. Exceptions exist, including strict vegans, people with malabsorption conditions, and infants receiving the standard newborn injection. Outside those groups, supplements fill a gap rather than replace a foundation.
K1, K2, and the MK-4 vs MK-7 Question
Standalone K1 supplements work for people who avoid leafy greens entirely but want to protect clotting. Standalone K2 products split into two camps: MK-4, which requires split doses through the day because of its short half-life, and MK-7, which lasts long enough for once-daily dosing. MK-7 at 100 to 200 micrograms is the most practical option for bone and vascular support, while MK-4 trials on bone density used doses of 1,000 to 45,000 micrograms split into three daily servings.
Combined Products and Stack Formulas
K2 with vitamin D3 is a sensible pairing, since D3 drives calcium absorption and K2 directs that calcium into bone rather than soft tissue. Magnesium often joins the stack, because magnesium deficiency independently weakens bone. Calcium itself is sometimes included, though most people get enough from food. The pairing adds real value when the individual has confirmed low intake of any of these nutrients; otherwise, it adds cost without measurable benefit.
Skip standalone K1 unless a clinician has flagged a clotting-related deficiency. Most adults need K2 support, not K1.
Blood Thinners, Infants, and the Safety Layer Nobody Wants to Discuss
Warfarin (Coumadin) works by blocking vitamin K, which is why sudden dietary changes destabilize INR, the blood-clotting measure used to dose the drug. The outdated advice to “avoid vitamin K” leads many patients to drop greens entirely and then swing wildly when one salad tips the scale. The newer approach keeps intake consistent, week after week, and adjusts the warfarin dose to match the diet rather than the other way around.
DOACs vs Warfarin: A Critical Distinction
Direct oral anticoagulants (apixaban, rivaroxaban, dabigatran, edoxaban) work through specific clotting factors and are not affected by dietary vitamin K at all. A patient on apixaban can eat spinach every day without INR worries, because INR is not even measured for these drugs. Many patients and even some prescribers miss this distinction, which leaves people needlessly scared of greens or, worse, misinformed about their medication.
The Newborn Vitamin K Shot
Hemorrhagic disease of the newborn can cause brain bleeds, gastrointestinal bleeding, or skin bruising within the first six months of life, and breast milk provides only a fraction of an infant’s clotting-vitamin requirement. The CDC and the American Academy of Pediatrics recommend a single intramuscular dose of vitamin K1 at birth as standard of care. Oral vitamin K regimens exist but require multiple doses and are easier to miss, leaving infants partially protected.
Your Action Framework
- Know your daily mcg: Track leafy greens and fermented foods for one normal week to set a baseline.
- Keep intake steady: Consistency matters more than absolute amount for warfarin users.
- Tell every prescriber: List every supplement on every medication review, including the dose.
- Recheck after diet changes: A new greens habit or a new supplement warrants a follow-up INR for warfarin patients within a week or two.
Putting It Together: A Simple Weekly Pattern That Actually Works
Run two tracks in parallel: a K1 base built around leafy greens paired with fat, and a K2 layer matched to your diet. Natto or aged cheese covers K2 if you tolerate fermented foods; eggs and poultry carry MK-4 for omnivores; a daily MK-7 supplement covers vegans and anyone who skips fermented foods entirely. Numbers worth memorizing: 90 to 120 micrograms per day as the floor, 200 to 400 micrograms as typical real intake, and serving sizes in cups or ounces rather than vague “high in K” labels.
Medication rules stay simple. Warfarin users keep intake consistent rather than low. DOAC users face no dietary restriction at all. Newborns receive the standard vitamin K injection unless a pediatrician counsels otherwise. For most adults, food alone is enough; supplements are a targeted tool, not a default. Anyone experiencing easy bruising, prolonged bleeding from small cuts, or unexplained bone loss should bring those symptoms to a clinician rather than self-prescribing.
FAQ
What foods are highest in vitamin K?
Cooked spinach, collard greens, and kale lead with roughly 770 to 889 micrograms of K1 per cooked cup. Natto tops the K2 list at over 1,000 micrograms per small serving as MK-7, followed by aged cheeses, egg yolks, and chicken thighs.
How much vitamin K do I need per day?
Adult men need 120 micrograms per day and adult women need 90 micrograms, with the goal of supporting normal blood clotting. Most people exceed that minimum easily with a few servings of greens each week, though K2 targets are higher for bone and vascular goals.
Can you get enough vitamin K from diet alone?
Most omnivores clear the K1 requirement with daily greens and pick up enough K2 from eggs, dairy, and poultry. Vegans and people with fat malabsorption often fall short on K2, which is where fermented foods or supplements enter the picture.
What happens if you don’t get enough vitamin K?
Mild deficiency shows up as easy bruising, prolonged bleeding from small cuts, heavy menstrual flow, and in older adults, faster bone density loss. Severe deficiency causes spontaneous bleeding and is a medical emergency, though it is rare in healthy adults outside of newborn infants.
Does vitamin K2 come from food or supplements?
Both. Natto, aged cheeses, egg yolks, and chicken deliver K2 naturally, with natto far ahead of the rest. Supplements using MK-7 from natto or fermented chickpea offer a reliable alternative when dietary sources are limited or unappealing.
Why do newborns need a vitamin K shot?
Newborns have almost no vitamin K stored at birth, breast milk provides only trace amounts, and their gut bacteria have not yet established the production that adults rely on. A single intramuscular vitamin K1 dose at birth prevents hemorrhagic disease and the serious brain bleeds that can come with it.
