Vitamin K: Recommended Dietary Allowance (RDA), Dietary Sources, and Its Role in Health and Disease

Introduction

Vitamin K is an essential nutrient that plays a crucial role in blood clotting, bone metabolism, and cardiovascular health. This fat-soluble vitamin exists in two major forms: K1 (phylloquinone) and K2 (menaquinone), each with distinct physiological functions.

Recommended Dietary Allowance (RDA)

The RDA for vitamin K varies by age, gender, and life stage. According to dietary guidelines:

• Adult men: 120 mcg/day
• Adult women: 90 mcg/day
• Infants and children: 2-75 mcg/day, depending on age

Dietary Sources

Vitamin K1 is predominantly found in leafy green vegetables, while K2 is sourced from fermented foods and animal products. Some rich dietary sources include:

• Spinach, kale, and broccoli (high in K1)
• Natto (fermented soybeans, high in K2)
• Dairy, eggs, and meat (moderate K2 content)

Role in Health and Disease

Vitamin K is essential for:

• Blood Clotting: Supports production of coagulation factors.
• Bone Health: Enhances calcium-binding proteins to strengthen bones.
• Heart Health: Prevents arterial calcification and maintains vascular function.

Vitamin K Toxicity: Risks and Effects of Excessive Intake

While vitamin K toxicity is rare due to its water-insoluble nature, excessive intake of synthetic forms may lead to complications:

• Increased risk of clot formation
• Drug interactions with anticoagulants
• Liver toxicity in extreme cases

Conclusion

Vitamin K is indispensable for vital bodily functions, and maintaining adequate intake is essential for overall health. While toxicity is uncommon, balanced consumption from natural sources is recommended to prevent deficiency-related disorders.