Comprehensive Guide to Vitamin K: Functions, Sources, and Health Benefits

Vitamin K is a fat-soluble vitamin that plays a crucial role in various bodily functions, primarily associated with blood clotting and bone health. Here's an overview of its key aspects and benefits:

Functions and Benefits of Vitamin K

1. Blood Clotting

   • Vitamin K is essential for synthesizing certain proteins required for blood clotting. Without it, the body cannot produce clotting factors II, VII, IX, and X, which are necessary to prevent excessive bleeding¹².
   • It is often referred to as the "clotting vitamin". Newborns typically receive a vitamin K injection to prevent bleeding issues.

2. Bone Health

   • Vitamin K is involved in the carboxylation of osteocalcin, a protein that binds calcium to bones. Adequate levels of vitamin K are associated with better bone density and a lower risk of fractures³.
   • Studies indicate that vitamin K supplementation, particularly with the form known as menaquinone (MK-4), can improve bone mineral density and reduce the incidence of fractures⁴⁵.

3. Cardiovascular Health

   • Research suggests that vitamin K helps prevent arterial calcification, thereby supporting cardiovascular health⁶.

4. Other Benefits

   • Emerging studies associate vitamin K with other roles, including anti-inflammatory effects, cognitive support, and potential anticancer properties⁷.

Sources of Vitamin K

Vitamin K exists in two main forms:

• Vitamin K1 (Phylloquinone): Found primarily in green leafy vegetables such as kale, spinach, and broccoli.
• Vitamin K2 (Menaquinone): Found in some animal products and fermented foods. The body can also synthesize it in the gut.

Foods high in vitamin K include:

• Green leafy vegetables (e.g., kale, spinach, turnip greens)
• Brussels sprouts, broccoli, and cabbage
• Fish, liver, meat, eggs, and cereals (contain smaller amounts)⁸.

Dietary Recommendations and Deficiency

• Adequate Intake (AI): Varies by age and sex. For adults, the AI is 120 micrograms per day for men and 90 micrograms per day for women⁹.
• Deficiency: Rare but can lead to increased bleeding and bruising. Long-term antibiotic use or conditions affecting nutrient absorption can result in deficiency¹⁰.

Supplementation Considerations

• Warfarin (Coumadin): People on blood thinners need consistent vitamin K intake to avoid interference with medication efficacy¹¹.
• Safety: There is no known toxicity associated with high intakes of vitamin K1 or K2, although allergic reactions are possible¹².

By ensuring a balanced intake of vitamin K through diet or supplements, individuals can help maintain proper blood clotting functions and support bone health.

Footnotes

1. MedlinePlus Medical Encyclopedia - Vitamin K ↩

2. NCBI Bookshelf - Vitamin K: StatPearls ↩

3. Office of Dietary Supplements - Vitamin K ↩

4. NCBI - Vitamin K as a Diet Supplement with Impact in Human Health ↩

5. NCBI Bookshelf - Vitamin K Deficiency ↩

6. NCBI - PubMed, The health benefits of vitamin K ↩

7. NCBI Bookshelf - Vitamin K Deficiency ↩

8. Harvard T.H. Chan School of Public Health - Vitamin K ↩

9. MedlinePlus Medical Encyclopedia - Vitamin K ↩

10. Office of Dietary Supplements - Vitamin K ↩

11. Harvard T.H. Chan School of Public Health - Vitamin K ↩

12. StatPearls - Vitamin K ↩