Vitamin K: Understanding Recommended Doses, Sources, and the Need for Supplementation

Vitamin K, an essential nutrient known for its role in blood clotting and bone health, is found in various food sources and also produced by gut bacteria. The recommended daily allowance (RDA) varies with age, gender, and life stage, with specific recommendations for certain groups like newborns and individuals on anticoagulant therapy. This article explores the recommended doses, dietary sources, and circumstances necessitating supplementation of Vitamin K.

The recommended dose of Vitamin K varies across different age groups. For adults, the RDA is approximately 90-120 micrograms. Dietary sources rich in Vitamin K include green leafy vegetables, such as spinach, kale, and broccoli, as well as some vegetable oils and fruits (Holvik et al., 2019). However, certain conditions, like long-term use of antibiotics or intestinal malabsorption disorders, can impede the absorption of Vitamin K, necessitating supplementation.

Newborns are particularly vulnerable to Vitamin K deficiency due to low placental transfer of the vitamin and a sterile intestinal tract at birth. Prophylactic administration of Vitamin K at birth is standard practice to prevent hemorrhagic disease of the newborn (Ng & Loewy, 2018). The recommended dose for infants is typically a single shot of 0.5 to 1 milligram of Vitamin K1.

Certain medications, like anticoagulants, can interfere with Vitamin K metabolism. Patients on warfarin, for instance, need to maintain a consistent intake of Vitamin K to prevent fluctuations in medication effectiveness and reduce the risk of blood clots or bleeding (Gajic-Veljanoski et al., 2012). In these cases, supplementation or dietary adjustments may be necessary under medical supervision.

While Vitamin K is available through diet and produced endogenously, specific populations, such as newborns and individuals on certain medications, may require supplementation. It’s important to consult healthcare providers for personalized advice on Vitamin K intake, especially for individuals with medical conditions or on medications that affect Vitamin K metabolism.


Holvik, K., Frøyland, L., Haugen, M., Henjum, S., Løvik, M., Stea, T. H., Strand, T. A., & Parr, C. L. (2019). Assessment of Dietary Intake of Vitamin K and Maximum Limits for Vitamin K in Food Supplements.

Ng, E., & Loewy, A. D. (2018). Guidelines for vitamin K prophylaxis in newborns. Paediatrics and Child Health, 23(5), 293-297.

Gajic-Veljanoski, O., Bayoumi, A. M., Tomlinson, G., Khan, K., & Cheung, A. M. (2012). Vitamin K supplementation for the primary prevention of osteoporotic fractures: Is it cost-effective and is future research warranted? Osteoporosis International, 23(11), 2681-2692.

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