Nutrition Diet: Who is Prone to Vitamin K Deficiency?

October 14, 2025 •

4 min read

Approximately 1 in 60 to 1 in 250 newborns who do not receive a vitamin K injection are at risk for early or classic Vitamin K Deficiency Bleeding (VKDB). Understanding who is prone to vitamin K deficiency is vital for prevention and early intervention across all age groups, given the vitamin's critical role in blood clotting and bone health.

Quick Summary

Individuals at high risk for vitamin K deficiency include newborns, people with fat malabsorption disorders, liver disease patients, and those using certain medications like warfarin or long-term antibiotics.

Key Points

Newborn Risk: Due to low placental transfer and a sterile gut, all infants are at risk for Vitamin K Deficiency Bleeding (VKDB) without prophylactic treatment.
Malabsorption Issues: Any condition hindering fat absorption, such as cystic fibrosis, celiac disease, or liver disease, can prevent proper vitamin K uptake.
Medication Interference: Anticoagulants like warfarin intentionally interfere with vitamin K function, requiring careful dietary management to avoid bleeding complications.
Long-term Antibiotics: The prolonged use of broad-spectrum antibiotics can deplete gut bacteria responsible for producing vitamin K, increasing risk, especially with poor intake.
Liver Disease: Impaired liver function reduces the synthesis of vitamin K-dependent clotting factors, significantly increasing bleeding risk.
Prevention is Key: For high-risk groups, prevention through standard medical procedures for newborns, medication management, and addressing underlying illnesses is crucial.

Understanding Vitamin K's Role

Vitamin K is an essential, fat-soluble vitamin that plays a critical role in the body, primarily in the coagulation (blood clotting) process. The body uses vitamin K to produce several proteins, including clotting factors II (prothrombin), VII, IX, and X, which are synthesized in the liver. Without sufficient vitamin K, the liver produces inactive clotting factors, leading to impaired blood clotting and an increased risk of bleeding. Scientists also believe that vitamin K contributes to bone health, affecting bone mineralization and growth.

Vitamin K is found in two main forms: K1 (phylloquinone), from leafy green vegetables, and K2 (menaquinones), produced by bacteria in the gut. A healthy adult body can typically maintain adequate vitamin K levels through diet and internal production, making a deficiency rare. However, certain conditions and circumstances disrupt this balance, placing specific populations at significant risk.

Key Risk Groups for Vitamin K Deficiency

Newborns and Infants

Newborns are the most prominent and well-recognized group prone to vitamin K deficiency, which can cause a life-threatening condition called Vitamin K Deficiency Bleeding (VKDB). This vulnerability is due to several physiological factors:

Low placental transfer: Very little vitamin K passes from the mother to the fetus during pregnancy.
Sterile gut at birth: Newborns' intestines lack the bacteria needed to produce vitamin K2 in their first few days of life.
Low vitamin K in breast milk: While beneficial in many ways, breast milk contains low amounts of vitamin K, further contributing to the risk in exclusively breastfed infants.

Because of these factors, routine vitamin K prophylaxis (a vitamin K injection) is administered to newborns shortly after birth to prevent VKDB.

Conditions Affecting Fat Absorption

As a fat-soluble vitamin, vitamin K requires dietary fat for proper absorption in the small intestine. Any condition that impairs the absorption of fat can lead to a deficiency. These include:

Cystic Fibrosis (CF): A genetic disorder that often causes pancreatic insufficiency, preventing the release of enzymes needed for fat digestion and absorption.
Celiac Disease: An autoimmune disorder where gluten consumption damages the lining of the small intestine, leading to malabsorption of various nutrients, including vitamin K.
Chronic Diarrhea: Persistent, long-term diarrhea can significantly reduce the amount of time nutrients have to be absorbed.
Inflammatory Bowel Diseases (IBD): Conditions like Crohn's disease and ulcerative colitis cause chronic inflammation of the digestive tract, which interferes with nutrient absorption.
Biliary Tract or Liver Disease: The liver produces bile salts, which are necessary for fat absorption. Impaired liver function or blocked bile ducts can therefore cause a vitamin K deficiency.
Bariatric Surgery: Surgical procedures that modify the digestive system, such as weight-loss surgery, can alter absorption pathways.

Impact of Certain Medications

Some medications can interfere with the body's vitamin K levels or its function:

Anticoagulants (like warfarin): This type of blood-thinner works by actively antagonizing vitamin K, blocking its ability to activate clotting factors. Patients on these medications must carefully manage their vitamin K intake to maintain a consistent dosage effect.
Long-term Antibiotics: The long-term use of broad-spectrum antibiotics can disrupt the gut bacteria responsible for producing vitamin K2. This risk is heightened in individuals with poor dietary intake.
Anti-seizure Medications: Some anti-seizure drugs, such as phenytoin, can interfere with vitamin K metabolism, increasing risk for both mothers taking the medication and their newborns.

Other Risk Factors

Malnutrition or Poor Diet: While rare in healthy individuals, severe malnutrition or diets extremely low in green vegetables can lead to a deficiency.
Total Parenteral Nutrition (TPN): Patients receiving TPN for extended periods without adequate vitamin K supplementation are at risk.

Comparative Risk: Newborns vs. Adults


Factor	Newborns	Adults	Comments
Primary Cause	Poor placental transfer, low breast milk content, sterile gut	Fat malabsorption, medications, liver disease	The cause is physiological in newborns versus pathological or pharmacological in adults.
Risk Level	High without prophylaxis	Low in healthy individuals; high in at-risk groups	A healthy adult's body recycles and produces some vitamin K, which newborns cannot do efficiently.
Preventive Action	Routine intramuscular injection at birth	Dietary adjustments, addressing underlying medical conditions, supplementation if necessary	Prophylaxis is standard for newborns, whereas adult prevention is targeted based on risk factors.
Severity	Life-threatening bleeding (VKDB), including intracranial hemorrhage	Less common but can lead to severe bleeding; often preceded by easier bruising	Intracranial bleeding in infants is a severe consequence of untreated VKDB.
Diagnosis	Often diagnosed based on clinical signs and risk factors, confirmed by blood tests	Based on medical history, specific risk factors, and blood tests like PT/INR	Elevated PT/INR indicates clotting impairment, a late sign of deficiency.

Preventing Vitamin K Deficiency

Prevention is critical, especially for those in high-risk categories. Strategies include:

Neonatal Prophylaxis: All newborns should receive a single vitamin K injection at birth to prevent VKDB.
Addressing Malabsorption: For individuals with conditions like CF, celiac disease, or liver disease, managing the underlying disorder and possibly taking supplements is crucial.
Medication Monitoring: Patients on warfarin must maintain a consistent dietary intake of vitamin K-rich foods and be regularly monitored by a physician. Those on long-term antibiotics should discuss supplementation with their doctor.
Dietary Diversity: Healthy individuals can typically prevent deficiency by consuming a balanced diet rich in vitamin K sources, such as kale, spinach, and broccoli.

Conclusion

While uncommon in healthy adults, vitamin K deficiency poses a significant risk to several specific populations, most notably newborns. For adults, chronic health conditions that impair fat absorption, such as cystic fibrosis and liver disease, are the primary culprits. Certain medications, including anticoagulants like warfarin and prolonged antibiotic courses, also increase risk. A proactive approach involving universal neonatal prophylaxis, medical management of underlying diseases, and careful medication monitoring is essential to prevent the serious bleeding complications associated with vitamin K deficiency. If you are concerned about your risk, consulting a healthcare provider is the best course of action.

For more detailed information on vitamin K, visit the National Institutes of Health Office of Dietary Supplements: https://ods.od.nih.gov/factsheets/VitaminK-Consumer/

Frequently Asked Questions

Newborns are at high risk due to limited transfer of vitamin K from the mother's placenta, low amounts in breast milk, and a sterile gut that has not yet developed bacteria to produce vitamin K.

Yes, long-term use of broad-spectrum antibiotics can destroy the gut bacteria that produce some of the body's vitamin K2, potentially leading to a deficiency, especially in people with poor dietary intake.

Conditions that impair fat absorption in the digestive tract, such as cystic fibrosis, celiac disease, chronic diarrhea, and liver or biliary tract diseases, can all lead to vitamin K malabsorption.

Warfarin is an anticoagulant that works by blocking the action of vitamin K in the body. Patients on this medication must maintain a consistent intake of vitamin K to ensure the dosage remains effective and safe.

No, vitamin K deficiency is rare in healthy adults because the body gets sufficient amounts from a varied diet, and gut bacteria produce some as well. Deficiency is primarily a concern for high-risk populations.

The main symptoms include easy bruising, excessive bleeding from wounds or injection sites, and mucosal bleeding (such as nosebleeds or blood in the stool). In newborns, it can cause severe bleeding within the body, including the brain.

The standard and most effective prevention method is a single vitamin K injection given to the newborn within the first hour of birth. This significantly reduces the risk of Vitamin K Deficiency Bleeding (VKDB).