UPSC MainsAGRICULTURE-PAPER-I201910 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. First, classify vitamins broadly (fat-soluble vs. water-soluble). Then, specifically address Vitamin K, detailing its functions and sources. The response should be concise and precise, highlighting key aspects within the word limit. A table summarizing Vitamin K sources would be beneficial. Emphasis should be placed on the physiological significance of Vitamin K and its importance in human health.

Model Answer

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Introduction

Vitamins are organic compounds required in small amounts for normal metabolic function. They are essential micronutrients that the human body cannot synthesize and must be obtained from external sources, primarily through diet. Vitamins are broadly classified based on their solubility – either fat-soluble (A, D, E, K) or water-soluble (B vitamins and C). Deficiencies in vitamins can lead to a range of health problems, highlighting their critical role in maintaining overall well-being. The question specifically asks about Vitamin K, a vital nutrient for blood coagulation.

Classification of Vitamins

Vitamins are categorized into two main groups based on their solubility:

  • Fat-Soluble Vitamins: These are soluble in fats and oils and are stored in the body's fatty tissues and liver. Examples include Vitamins A, D, E, and K. They are not readily excreted and can accumulate to toxic levels if consumed in excess.
  • Water-Soluble Vitamins: These are soluble in water and are not stored in the body to a significant extent. Excess amounts are usually excreted in urine. Examples include Vitamin C and the B vitamins (B1, B2, B3, B5, B6, B7, B9, B12).

Vitamin K: The Blood Clotting Vitamin

Vitamin K, named after the German word "Koagulation," is a group of structurally similar compounds that play a crucial role in blood clotting and bone metabolism. There are two main forms: Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinone).

Functions of Vitamin K

  • Blood Clotting: Vitamin K is essential for the synthesis of several clotting factors (II, VII, IX, and X) in the liver. These factors are crucial for the coagulation cascade, preventing excessive bleeding.
  • Bone Health: It helps in the carboxylation of osteocalcin, a protein involved in bone mineralization and calcium binding. Vitamin K contributes to bone density and strength.
  • Vascular Health: May play a role in preventing arterial calcification and maintaining vascular elasticity.

Sources of Vitamin K

Vitamin K Form Sources
Vitamin K1 (Phylloquinone) Green leafy vegetables (spinach, kale, collard greens), broccoli, Brussels sprouts.
Vitamin K2 (Menaquinone) Fermented foods (natto, sauerkraut), animal products (liver, cheese, egg yolks), produced by bacteria in the gut.

Deficiency and Considerations

Vitamin K deficiency is relatively rare in adults but can occur in newborns (due to sterile gut and limited placental transfer), individuals with fat malabsorption syndromes, or those taking certain medications (e.g., anticoagulants). Newborns routinely receive a Vitamin K injection shortly after birth to prevent hemorrhagic disease.

Conclusion

In conclusion, vitamins are essential organic compounds classified as either fat-soluble or water-soluble, each playing distinct roles in maintaining health. Vitamin K, specifically, is critical for blood clotting and bone metabolism, obtained from both plant and microbial sources. Adequate intake through diet is generally sufficient, but deficiency can occur in specific populations, highlighting the importance of nutritional awareness and, when necessary, supplementation. The ongoing Poshan Abhiyaan underscores the commitment to addressing nutritional deficiencies, ensuring a healthier populace.

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

Carboxylation
A chemical reaction involving the addition of a carboxyl group (-COOH) to a molecule. Crucial for Vitamin K's function in activating clotting factors and osteocalcin.
Menaquinone
A form of Vitamin K2, produced by bacteria in the gut and found in fermented foods and animal products. It has several subtypes (MK-4, MK-7, etc.) with varying biological activity.

Key Statistics

Approximately 1 mg of Vitamin K is required daily for adults (National Institutes of Health).

Source: NIH

The gut microbiome synthesizes menaquinones (MK-7 and MK-8) contributing significantly to the body’s Vitamin K2 pool. (Source: American Journal of Clinical Nutrition, 2018)

Source: American Journal of Clinical Nutrition, 2018

Examples

Newborn Hemorrhagic Disease

A condition affecting newborns due to Vitamin K deficiency, leading to excessive bleeding. Routine Vitamin K injections prevent this.

Frequently Asked Questions

Can I get enough Vitamin K from my diet?

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

Topics Covered

BotanyNutritionPlant PhysiologyVitaminsNutritionPlant Metabolism