UPSC MainsAGRICULTURE-PAPER-II201910 Marks150 Words
Q15.

How are vitamins classified? Name the blood clotting vitamin. Give its various functions and sources.

How to Approach

This question requires a structured response, beginning with a classification of vitamins, followed by identifying Vitamin K and detailing its functions and sources. The answer should be concise, accurate, and demonstrate understanding of biochemistry and nutrition. A tabular format can be employed to present sources of Vitamin K effectively. Emphasis should be placed on clarity and precision, catering to the examiner's expectations of a UPSC Mains answer.

Model Answer

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Introduction

Vitamins are organic compounds required in small amounts for normal physiological function. They are classified based on their solubility—either fat-soluble (A, D, E, K) or water-soluble (B vitamins and C). These micronutrients are essential for various metabolic processes and cannot be synthesized by the body in sufficient quantities, necessitating their intake through diet or supplementation. Vitamin K, specifically, plays a vital role in blood coagulation and bone health, often overlooked compared to other vitamins. Understanding its classification, functions, and sources is crucial for maintaining overall health.

Classification of Vitamins

Vitamins are broadly classified into two categories based on their solubility:

  • Fat-Soluble Vitamins: These vitamins are soluble in fats and oils and are stored in the body's fatty tissues and liver. They are Vitamins A, D, E, and K. Excess intake can lead to toxicity.
  • Water-Soluble Vitamins: These vitamins dissolve in water and are not stored in the body to a significant extent. They are excreted in urine. They include the B vitamins (B1, B2, B3, B5, B6, B7, B9, B12) and Vitamin C. Deficiency is more common than toxicity.

Vitamin K: The Blood Clotting Vitamin

Vitamin K, named for the German word "Koagulation," is a group of structurally similar compounds. Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinone) are the most important forms.

Functions of Vitamin K

  • Blood Coagulation: Vitamin K is essential for the synthesis of clotting factors II (prothrombin), VII, IX, and X. It acts as a cofactor for an enzyme (gamma-glutamyl carboxylase) that modifies these factors, allowing them to bind calcium and participate in the coagulation cascade.
  • Bone Health: Vitamin K plays a role in bone mineralization by activating osteocalcin, a protein involved in calcium binding to bone. This contributes to bone strength and density.
  • Vascular Health: Emerging research suggests Vitamin K may also be involved in preventing arterial calcification.

Sources of Vitamin K

Vitamin K Form Sources
Vitamin K1 (Phylloquinone) Green leafy vegetables (spinach, kale, broccoli), vegetable oils (soybean, canola), brussels sprouts.
Vitamin K2 (Menaquinone) Fermented foods (natto, sauerkraut), animal products (meat, eggs, dairy), synthesized by bacteria in the gut.

Deficiency and Considerations

Vitamin K deficiency is relatively rare in adults but can occur in newborns (who have sterile guts and limited stores) and individuals with malabsorption syndromes. Anticoagulant medications (like warfarin) also interfere with Vitamin K's function.

Recent Developments

Research is ongoing to explore the role of different forms of Vitamin K2 (menaquinones) in bone and cardiovascular health. The "Ornish Diet" emphasizes Vitamin K2 rich foods for cardiovascular benefits.

Conclusion

In conclusion, vitamins are classified based on solubility, with Vitamin K being a crucial fat-soluble vitamin vital for blood clotting and bone health. Understanding its classification, functions, and diverse sources—ranging from leafy greens to fermented foods—is essential for maintaining optimal health and preventing deficiencies. Further research continues to illuminate the complex roles of Vitamin K in various physiological processes, highlighting its importance in preventative healthcare.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Micronutrients
Micronutrients are essential nutrients required by the body in small amounts for various physiological functions. Vitamins and minerals fall under this category.
Coagulation Cascade
The coagulation cascade is a complex series of enzymatic reactions that ultimately leads to the formation of a blood clot.

Key Statistics

Approximately 12% of children under five worldwide suffer from Vitamin A deficiency, impacting vision and immune function. (WHO, 2021)

Source: World Health Organization

The recommended daily allowance (RDA) for Vitamin K is 90 mcg for adult men and 60 mcg for adult women.

Source: National Institutes of Health

Examples

Newborn Vitamin K Injection

Newborns routinely receive a Vitamin K injection shortly after birth to prevent hemorrhagic disease of the newborn, a potentially life-threatening bleeding disorder.

Frequently Asked Questions

Can I get enough Vitamin K from diet alone?

For most individuals, a balanced diet rich in green leafy vegetables and fermented foods can provide adequate Vitamin K. However, certain conditions or medications may necessitate supplementation.

Topics Covered

BotanyNutritionPlant PhysiologyVitaminsNutritionPlant Metabolism