Vitamin K

Overview

Vitamin K is a fat-soluble vitamin essential for blood clotting, bone health, and cardiovascular stability. As described in the document (page 2), the body stores Vitamin K in the liver, brain, heart, pancreas, and bone, and it is best absorbed when consumed with dietary fat.

Vitamin K exists in two primary forms (page 3):

1. Phylloquinone (K1) – found in plants, especially leafy vegetables
2. Menaquinone (K2) – produced in small amounts by intestinal bacteria and also available from animal foods

Vitamin K enables the synthesis of clotting proteins that prevent excessive bleeding and supports tissue integrity across multiple organs. Its functions (page 5) include regulating blood sugar, reducing menstrual pain, protecting immunity, preventing osteoporosis, lowering heart disease risk, and preventing hemorrhage in newborns. Because of its broad role, deficiency can contribute to bleeding disorders, bruising, and weakened bones.

Symptoms

Symptoms of Vitamin K Deficiency

The document’s deficiency section (page 12) outlines symptoms in both newborns and adults.

In Newborns

1. High bleeding risk due to poor placental transfer of Vitamin K
2. Immature liver with limited prothrombin synthesis
3. Sterile gut in early days, reducing endogenous K2 production
4. Low Vitamin K in breast milk (around 2.5 mcg/L)

These factors may result in hemorrhagic disease of the newborn, presenting as bleeding from the umbilicus, gastrointestinal tract, skin, or brain.

In Adults

1. Excessive bleeding from minor injuries
2. Easy bruising
3. Nosebleeds
4. Bleeding gums
5. Prolonged clotting
6. Weak bones or bone pain due to impaired mineralization
7. Increased menstrual flow

These symptoms reflect insufficient activation of Vitamin K–dependent clotting factors (II, VII, IX, X).

Symptoms of Vitamin K Toxicity

Although toxicity is rare (page 13), excessive supplementation may lead to:

1. Allergic reactions
2. Interference with medications like blood thinners
3. Hemolytic anemia due to RBC rupture
4. Jaundice, especially in newborns, which may progress to kernicterus

Causes

1. Inadequate Intake of Vitamin K

Not consuming enough leafy vegetables, dairy, or animal products may lead to a deficiency (page 12).

2. Fat Malabsorption

Conditions such as biliary obstruction, cystic fibrosis, pancreatitis, or intestinal malabsorption disorders reduce absorption of fat-soluble vitamins, including Vitamin K.

3. Medication Interference

Coumarin anticoagulants disrupt the synthesis of Vitamin K-dependent clotting proteins (page 12).

Certain antibiotics (cephalosporins and broad-spectrum types), salicylates, and megadoses of Vitamin E also elevate bleeding risk by lowering Vitamin K function.

4. Liver Disease

Since Vitamin K-related factors are produced in the liver, hepatic insufficiency contributes to deficiency.

5. Low Vitamin K in Breast Milk

Newborns relying on breast milk alone are vulnerable due to naturally low Vitamin K content (page 12).

6. Excess Supplementation

High intake may result in toxicity symptoms outlined on page 13.

Risk Factors

1. Newborns

The document identifies newborns as the highest-risk group due to sterile gut flora, poor placental transfer, and low Vitamin K in breast milk (page 12).

2. Adults With Fat Malabsorption Disorders

Patients with cystic fibrosis, pancreatitis, Crohn’s disease, coeliac disease, or post–intestinal surgery have a higher deficiency risk.

3. Individuals on Anticoagulants

Warfarin or coumarin therapy disrupts Vitamin K pathways and requires monitoring (page 7).

4. Long-Term Antibiotic Users

Broad-spectrum antibiotics reduce gut bacteria that produce menaquinone (K2).

5. Liver Disease Patients

Liver disorders impair the production of clotting proteins that depend on Vitamin K.

6. Poor Diet Quality

A diet low in leafy greens and K2-rich foods increases deficiency risk (page 4).

7. Formula-Fed Infants

More prone to jaundice-related complications, including potential kernicterus (page 13).

Prevention

1. Adequate Dietary Intake

The document lists rich sources of K1, such as spinach, kale, broccoli, lettuce, turnips, collards, carrots, grapes, blueberries, and vegetable oils, and K2 sources like dairy, pork, beef, liver, chicken, eggs, and fatty fish (page 4).

2. Routine Newborn Prophylaxis

Vitamin K injections prevent Vitamin K Deficiency Bleeding (page 14). This is a critical preventive measure.

3. Manage Underlying Conditions

Treating malabsorption disorders, pancreatic disease, or obstructive liver disease helps prevent deficiency (page 12).

4. Medication Monitoring

People on anticoagulants require Vitamin K level monitoring to balance clotting and avoid excessive bleeding (page 7).

5. Proper Sample Collection for Testing

(Page 9–10)

1. Fast 12 hours
2. Avoid alcohol for 24 hours
3. Collect 3.0 mL of blood in an EDTA or plain tube
4. Separate serum/plasma early
5. Store at 2–8°C

6. Avoid Excess Supplementation

Since toxicity is possible, Vitamin K supplements should be taken only under medical supervision (page 13).