,Introduction
Micronutrients, though required in minute quantities, are essential for optimal growth, development,
and physiological functions. They include vitamins (water- and fat-soluble), minerals, and trace
elements. Deficiency or excess can lead to clinical manifestations, subclinical disorders, or long-term
health consequences.
Goal of micronutrient requirements:
• Maintain biochemical and physiological functions.
• Prevent deficiency diseases.
• Optimize health across all life stages.
Classification of Micronutrients
Category Examples Primary Functions
Water-Soluble B-complex (B1, B2, B3, B6, B12, Folate, Coenzymes in metabolism, antioxidant
Vitamins Biotin, Pantothenic acid), Vitamin C functions, tissue repair
Fat-Soluble Vision, bone health, antioxidant, blood
Vitamins A, D, E, K
Vitamins clotting
Calcium, Phosphorus, Magnesium, Structural (bones), fluid balance, nerve
Minerals
Sodium, Potassium & muscle function
Iron, Zinc, Copper, Iodine, Selenium, Enzyme cofactors, immunity, thyroid
Trace Elements
Manganese, Chromium function, antioxidant defense
Water-Soluble Vitamins
General Features
• Easily absorbed in the small intestine.
• Not stored in large amounts, excess excreted in urine → low risk of toxicity (except B6 &
niacin).
• Require daily intake.
Critical Evaluation of Requirement Methods
• Direct balance studies: Measure intake vs. excretion.
• Functional indicators:
• Enzyme activity (e.g., transketolase for thiamine).
• Biomarkers in blood/urine (e.g., serum folate).
• Dose-response curves: Relate intake to biochemical markers.
, • Limitations: inter-individual variability, bioavailability, physiological adaptation.
Example Flowchart: Determining Water-Soluble Vitamin Requirement
Dietary Intake → Blood/Biochemical Marker → Functional Test → Optimal Intake Determined
Fat-Soluble Vitamins
General Features
• Stored in liver and adipose tissue → lower daily requirement.
• Absorption depends on dietary fat and bile salts.
• Higher risk of toxicity (hypervitaminosis) than water-soluble vitamins.
Evaluation Methods
• Clinical assessment: Signs of deficiency (e.g., night blindness → Vitamin A).
• Biochemical markers: Serum retinol, 25(OH)D, alpha-tocopherol levels.
• Functional assessment: Coagulation profile for Vitamin K, bone density for Vitamin D.
Critical Points:
• Requirements depend on age, gender, physiological states (pregnancy/lactation).
• Bioavailability influenced by dietary matrix, fat content, interactions with other nutrients.
Minerals and Trace Elements
Essential Roles
• Structural: Calcium, Phosphorus
• Electrolyte balance: Sodium, Potassium
• Enzyme cofactors: Zinc, Magnesium, Iron
Methods to Determine Requirements
1. Balance studies: Intake vs. excretion.
2. Metabolic studies: Enzyme activity or functional outcomes.
3. Epidemiological correlation: Intake vs. disease prevalence.
Diagram: Steps to Derive Mineral Requirements
Dietary Intake → Absorption Studies → Biological Marker → Functional Outcome → Recommended
Allowance
Micronutrients, though required in minute quantities, are essential for optimal growth, development,
and physiological functions. They include vitamins (water- and fat-soluble), minerals, and trace
elements. Deficiency or excess can lead to clinical manifestations, subclinical disorders, or long-term
health consequences.
Goal of micronutrient requirements:
• Maintain biochemical and physiological functions.
• Prevent deficiency diseases.
• Optimize health across all life stages.
Classification of Micronutrients
Category Examples Primary Functions
Water-Soluble B-complex (B1, B2, B3, B6, B12, Folate, Coenzymes in metabolism, antioxidant
Vitamins Biotin, Pantothenic acid), Vitamin C functions, tissue repair
Fat-Soluble Vision, bone health, antioxidant, blood
Vitamins A, D, E, K
Vitamins clotting
Calcium, Phosphorus, Magnesium, Structural (bones), fluid balance, nerve
Minerals
Sodium, Potassium & muscle function
Iron, Zinc, Copper, Iodine, Selenium, Enzyme cofactors, immunity, thyroid
Trace Elements
Manganese, Chromium function, antioxidant defense
Water-Soluble Vitamins
General Features
• Easily absorbed in the small intestine.
• Not stored in large amounts, excess excreted in urine → low risk of toxicity (except B6 &
niacin).
• Require daily intake.
Critical Evaluation of Requirement Methods
• Direct balance studies: Measure intake vs. excretion.
• Functional indicators:
• Enzyme activity (e.g., transketolase for thiamine).
• Biomarkers in blood/urine (e.g., serum folate).
• Dose-response curves: Relate intake to biochemical markers.
, • Limitations: inter-individual variability, bioavailability, physiological adaptation.
Example Flowchart: Determining Water-Soluble Vitamin Requirement
Dietary Intake → Blood/Biochemical Marker → Functional Test → Optimal Intake Determined
Fat-Soluble Vitamins
General Features
• Stored in liver and adipose tissue → lower daily requirement.
• Absorption depends on dietary fat and bile salts.
• Higher risk of toxicity (hypervitaminosis) than water-soluble vitamins.
Evaluation Methods
• Clinical assessment: Signs of deficiency (e.g., night blindness → Vitamin A).
• Biochemical markers: Serum retinol, 25(OH)D, alpha-tocopherol levels.
• Functional assessment: Coagulation profile for Vitamin K, bone density for Vitamin D.
Critical Points:
• Requirements depend on age, gender, physiological states (pregnancy/lactation).
• Bioavailability influenced by dietary matrix, fat content, interactions with other nutrients.
Minerals and Trace Elements
Essential Roles
• Structural: Calcium, Phosphorus
• Electrolyte balance: Sodium, Potassium
• Enzyme cofactors: Zinc, Magnesium, Iron
Methods to Determine Requirements
1. Balance studies: Intake vs. excretion.
2. Metabolic studies: Enzyme activity or functional outcomes.
3. Epidemiological correlation: Intake vs. disease prevalence.
Diagram: Steps to Derive Mineral Requirements
Dietary Intake → Absorption Studies → Biological Marker → Functional Outcome → Recommended
Allowance
