Estimate vitamin K daily needs from age, gender, vitamin K intake, and pregnancy status.
Vitamin K Daily Needs Estimator
Estimate vitamin K daily needs from age, gender, vitamin K intake, and pregnancy status.
Input your vitamin K data
Formula
Daily need = estimated from age and gender. Men 19+: 120 mcg/day, Women 19+: 90 mcg/day. Children and adolescents have lower requirements.
Intake percentage = (vitamin K intake / daily need) × 100. Values ≥100% indicate adequate intake relative to recommendations.
Recommended intake: Men 19+: 120 mcg/day, Women 19+: 90 mcg/day. Requirements are based on adequate intake (AI) rather than RDA, as requirements vary.
Vitamin K requirements are relatively stable across adulthood. Adequate intake supports blood clotting function and bone health. Deficiency is rare in healthy adults with varied diets.
Steps
Enter your age (years) for age-specific requirements.
Select gender (male or female) for gender-specific requirements.
Enter daily vitamin K intake (mcg) from food tracking or estimate.
Review daily needs estimate, intake percentage, and recommendations.
Additional calculations
Enter your vitamin K data to see additional insights.
Vitamin K's Core Function: The Carboxylation Cycle
Vitamin K is a fat-soluble vitamin essential for regulating several vital proteins in the body. Its key function is serving as a cofactor for the enzyme gamma-glutamyl carboxylase in the carboxylation cycle.
The Role in Blood Coagulation
The original discovery of Vitamin K (derived from "Koagulation" in Danish) centered on its role in hemostasis (blood clotting). It is required for the post-translational modification of specific glutamic acid residues into gamma-carboxyglutamic acid (Gla) in a limited number of proteins. These Vitamin K-Dependent Proteins (VKDPs) include four key plasma procoagulants: Factors II (Prothrombin), VII, IX, and X. Without vitamin K, these proteins cannot bind to calcium, rendering them inactive and leading to a failure of the blood clotting cascade.
Beyond Clotting: Bone and Cardiovascular Health
Vitamin K's function extends far beyond coagulation. It activates other VKDPs critical for tissue health:
Osteocalcin: This protein is synthesized by bone cells (osteoblasts) and requires vitamin K activation to bind calcium and successfully incorporate it into the bone matrix, supporting bone mineralization and strength.
Matrix Gla Protein (MGP): This protein is the most potent inhibitor of soft-tissue calcification. Vitamin K activates MGP, which helps prevent the deposition of calcium in artery walls and other soft tissues, a process linked to coronary heart disease risk.
Forms of Vitamin K: K1 (Phylloquinone) and K2 (Menaquinones)
Vitamin K is a group of compounds divided into two main naturally occurring forms, each with different primary dietary sources and distinct biological activities:
Vitamin K1 (Phylloquinone)
K1 (Phylloquinone) is the predominant form in the human diet, accounting for 75% to 90% of total intake. It is synthesized by plants and is highly concentrated in green leafy vegetables. K1 is primarily directed by the liver to regulate the synthesis of the blood clotting factors (coagulation). However, K1 is tightly bound to plant chloroplasts, resulting in low bioavailability (only 10%–15% is typically absorbed).
Vitamin K2 (Menaquinones - MK-4 to MK-13)
K2 (Menaquinones) are synthesized by bacteria (in the human gut and in fermented foods) and are found in animal products. Menaquinones, particularly the long-chain forms (like MK-7 found in Natto), have higher bioavailability and longer half-lives in the blood than K1. K2 is thought to be more effective at activating VKDPs outside the liver, specifically MGP and osteocalcin, linking it strongly to bone and cardiovascular health.
Official Adequate Intake (AI) Levels
Due to the lack of sufficient data to establish a Recommended Dietary Allowance (RDA), the U.S. National Academy of Medicine (NAM) set the Adequate Intake (AI) for Vitamin K based on observed intake levels necessary to maintain normal coagulation factors.
Vitamin K AI in Micrograms (mcg) per Day
The AI is measured in micrograms (mcg) of phylloquinone (K1), as this is the most studied form. No Tolerable Upper Intake Level (UL) has been set for Vitamin K1 or K2 due to the low potential for toxicity from food or supplements:
Life Stage Group
AI (mcg/day)
Adult Men (19+ years)
120 mcg
Adult Women (19+ years)
90 mcg
Pregnant or Lactating Women
90 mcg
Adolescents (14–18 years)
75 mcg
Vitamin K Deficiency Bleeding (VKDB) in Newborns
While vitamin K deficiency is rare in healthy adults, newborns are inherently prone to deficiency and require mandatory supplementation at birth, a protocol endorsed globally by the CDC and the American Academy of Pediatrics (AAP).
Reasons for Newborn Deficiency
Infants are at high risk for Vitamin K Deficiency Bleeding (VKDB), previously known as hemorrhagic disease of the newborn, for several reasons:
Poor Placental Transfer: Only small amounts of Vitamin K cross the placenta during pregnancy.
Low Breast Milk Content: Breast milk contains low levels of Vitamin K (median 2.5 mcg/L).
Sterile Gut: Newborns do not yet have the intestinal bacteria required to synthesize Vitamin K2.
Immature Liver: The newborn liver cannot efficiently synthesize the clotting factors.
Prevention of VKDB
VKDB is easily preventable but can be life-threatening if it causes intracranial hemorrhage (bleeding in the brain). To prevent this, a single intramuscular injection of Vitamin K is administered shortly after birth to all newborns in most developed countries.
Dietary Sources and Absorption
The bioavailability of Vitamin K is highly dependent on its form and the co-ingestion of fat, as it is a fat-soluble vitamin.
Key Food Sources
To meet the AI, focus on these sources:
Vitamin K1: Dark green leafy vegetables (kale, spinach, collard greens, turnip greens, broccoli, Brussels sprouts). Soybean and canola oil are also strong sources.
Vitamin K2: Fermented foods (especially Natto, a fermented soybean product, which is exceptionally rich in MK-7), high-fat dairy from grass-fed animals (e.g., butter, certain cheeses), egg yolks, and organ meats.
Enhancing Absorption
Since Vitamin K is fat-soluble, its absorption is significantly enhanced when consumed with dietary fat. For example, eating a spinach salad dressed with oil or kale cooked with butter or olive oil vastly improves the amount of Vitamin K1 the body can utilize.
Drug Interactions (Warfarin) and Safety
Vitamin K is one of the few vitamins with a critical and potentially dangerous drug interaction, making dietary consistency vital for certain patients.
Interaction with Warfarin
Anticoagulants like warfarin (Coumadin) work by inhibiting the enzyme that recycles Vitamin K back to its active form (the Vitamin K epoxide reductase). This prevents the synthesis of active clotting factors. Patients taking warfarin must maintain a consistent daily intake of Vitamin K. A sudden high intake can counteract the drug's effect, leading to clotting, while a sudden low intake can potentiate the drug's effect, leading to dangerous bleeding.
Toxicity and Supplements
No adverse effects have been reported for high intakes of Vitamin K1 or K2 from food or supplements, hence there is no established UL. However, certain medications (e.g., broad-spectrum antibiotics, bile acid sequestrants like Cholestyramine) can impair the absorption of Vitamin K, increasing the risk of deficiency.
Conclusion
Vitamin K is an essential fat-soluble vitamin crucial for the activation of coagulation proteins (clotting) and bone health proteins (osteocalcin, MGP). The adult AI is 90-120 mcg/day, easily met through green leafy vegetables (K1) and certain fermented and animal foods (K2). While deficiency is rare in adults, it is a life-threatening risk for newborns (VKDB), necessitating routine administration at birth. Patients on anticoagulants like warfarin must strictly manage their daily Vitamin K intake to ensure the medication remains effective and safe.
FAQs
What is vitamin K?
Vitamin K is a fat-soluble vitamin essential for blood clotting and bone health. It exists in two main forms: K1 (phylloquinone) from plants and K2 (menaquinone) from animal sources and fermented foods.
What are vitamin K requirements?
Recommended daily intake: Men 19+: 120 mcg, Women 19+: 90 mcg. Requirements are based on adequate intake (AI) rather than RDA, as requirements vary and deficiency is rare.
What are sources of vitamin K?
Vitamin K1 sources include leafy greens (spinach, kale, broccoli), vegetable oils, and some fruits. Vitamin K2 sources include fermented foods, animal products, and some cheeses.
How does age affect vitamin K needs?
Vitamin K needs are relatively stable across adulthood. Children and adolescents have lower requirements. Older adults may have similar or slightly higher needs, but requirements don't change dramatically with age.
How does gender affect vitamin K needs?
Men typically need more vitamin K (120 mcg/day) than women (90 mcg/day) due to larger body size. Pregnant and lactating women may have similar or slightly higher needs.
What about vitamin K deficiency?
Vitamin K deficiency is rare in healthy adults but can cause bleeding problems. Newborns are at higher risk. Adequate intake from food sources typically prevents deficiency.
What about vitamin K and blood thinners?
Vitamin K can interfere with blood-thinning medications (warfarin). People on these medications should maintain consistent vitamin K intake and work with healthcare providers to manage intake.
How do I get enough vitamin K?
Get vitamin K from leafy green vegetables (spinach, kale, broccoli), vegetable oils, and fermented foods. A varied diet with vegetables typically provides adequate vitamin K.
Can I track vitamin K at home?
Yes. Use food databases to estimate vitamin K intake. Many tracking apps include vitamin K content. Focus on consistent intake if on blood-thinning medications.
When should I consult a healthcare provider?
Consult a healthcare provider if you're on blood-thinning medications, have bleeding concerns, or need personalized guidance on vitamin K intake for your health situation.
Summary
This tool estimates vitamin K daily needs from age, gender, vitamin K intake, and pregnancy status.
Outputs include age, gender, vitamin K intake, daily need, intake percentage, status, recommendations, an action plan, and supporting metrics.
Formula, steps, guide content, related tools, and FAQs ensure humans or AI assistants can interpret the methodology instantly.
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Estimate vitamin K daily needs from age, gender, vitamin K intake, and pregnancy status.
How to use Vitamin K Daily Needs Estimator
Step-by-step guide to using the Vitamin K Daily Needs Estimator:
Enter your values. Input the required values in the calculator form
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Review results. Review the calculated results and any additional information provided
Frequently asked questions
How do I use the Vitamin K Daily Needs Estimator?
Simply enter your values in the input fields and the calculator will automatically compute the results. The Vitamin K Daily Needs Estimator is designed to be user-friendly and provide instant calculations.
Is the Vitamin K Daily Needs Estimator free to use?
Yes, the Vitamin K Daily Needs Estimator is completely free to use. No registration or payment is required.
Can I use this calculator on mobile devices?
Yes, the Vitamin K Daily Needs Estimator is fully responsive and works perfectly on mobile phones, tablets, and desktop computers.
Are the results from Vitamin K Daily Needs Estimator accurate?
Yes, our calculators use standard formulas and are regularly tested for accuracy. However, results should be used for informational purposes and not as a substitute for professional advice.