Biochemicals

This section covers the key aspects of vitamins and nutrition - their biochemical roles, metabolic pathways, associated normal and abnormal states, and their fundamental properties

Biochemical Theory and Pathways

• Essential Nutrients: Vitamins are organic compounds required in small amounts for various biochemical processes, but cannot be synthesized adequately by the body
• Classification: Vitamins are classified as either water-soluble (B vitamins, vitamin C) or fat-soluble (vitamins A, D, E, K)
• General Metabolic Functions
  • Coenzymes: Act as coenzymes, essential for enzyme activity in metabolic reactions
  • Antioxidants: Protect cells from damage caused by free radicals
  • Hormone-Like Functions: Some have hormone-like effects, regulating gene expression
• Metabolic Pathways and Actions
  • Thiamin (B1): Coenzyme in carbohydrate metabolism
  • Riboflavin (B2): Coenzyme in redox reactions
  • Niacin (B3): Coenzyme in redox reactions
  • Pantothenic Acid (B5): Component of Coenzyme A
  • Pyridoxine (B6): Coenzyme in amino acid metabolism
  • Biotin (B7): Coenzyme in carboxylation reactions
  • Folate (B9): Coenzyme for one-carbon transfer reactions
  • Cobalamin (B12): Coenzyme for methionine synthase and methylmalonyl-CoA mutase
  • Ascorbic Acid (Vitamin C): Antioxidant, collagen synthesis
  • Vitamin A: Vision, cell differentiation, immune function
  • Vitamin D: Calcium and phosphate metabolism
  • Vitamin E: Antioxidant
  • Vitamin K: Blood clotting, bone metabolism
• Absorption, Transport, Storage, and Excretion
  • Water-soluble: Absorbed directly into the bloodstream, not stored significantly, excreted in urine
  • Fat-soluble: Absorbed with dietary fats, stored in the liver and adipose tissue, excreted in bile

Normal and Abnormal States

• Normal Nutritional States
  • Adequate dietary intake of essential nutrients
  • Normal absorption and utilization of nutrients
  • Maintenance of nutrient levels within the normal reference ranges
• Malnutrition: Imbalance resulting from inadequate or excessive nutrient intake
  • Undernutrition: Deficiency of one or more essential nutrients due to inadequate intake, impaired absorption, or increased requirements
  • Overnutrition: Excessive intake of nutrients, leading to nutrient toxicity and adverse health effects
• Specific Disorders
  • Vitamin Deficiencies: Scurvy (C), rickets (D), beriberi (B1), pellagra (B3)
  • Vitamin Toxicity: Liver damage (A), hypercalcemia (D), increased bleeding risk (E)
• Assessment
  • Dietary assessment, anthropometric measurements, biochemical tests, and clinical assessment are used to determine nutritional status

Properties

• Water-Soluble Vitamins
  • Soluble in water
  • Not stored in the body
  • Less risk of toxicity
  • Serve as coenzymes in metabolism
• Fat-Soluble Vitamins
  • Soluble in lipids
  • Stored in the body
  • Risk of toxicity
  • Involved in vision, bone metabolism, and antioxidant functions
• Key Chemical Characteristics
  • Varied chemical structures influencing their solubility, stability, and interactions with other compounds
• Stability and Reactivity
  • Susceptible to degradation from heat, light, air, and pH
• Active Forms
  • Converted into specific coenzymes or active forms to exert their biochemical functions

Clinical Significance

• Understanding these concepts is vital for
  • Diagnosing and managing nutritional disorders effectively
  • Providing personalized dietary recommendations
  • Developing public health strategies to prevent deficiencies and toxicities
  • Interpreting laboratory test results related to vitamin and nutrient status