Calcium and Vitamin D: Calcium is the mineral foundation for strong teeth and bones, while Vitamin D is the critical regulator that enables the absorption of calcium from the gut. A deficiency in either can lead to rickets in children or osteoporosis in adults.
Iron and Haemoglobin: Iron is the central component of the haemoglobin molecule found in red blood cells. Without sufficient iron from sources like red meat or spinach, the body cannot effectively transport oxygen to respiring tissues, resulting in fatigue.
Vitamin C and Collagen: Vitamin C is essential for the production of collagen, a structural protein found in skin, gums, and hair. Inadequate intake from citrus fruits leads to scurvy, characterized by bleeding gums and poor wound healing.
Vitamin A: This vitamin is required to synthesize the light-sensitive pigments in the retina. A lack of Vitamin A in the diet can severely impair night vision and overall eye health.
Life Stages and Growth: Young individuals require significantly more energy and protein per unit of body mass compared to older adults to support the rapid synthesis of new cells during growth. As humans age, their basal metabolic rate typically slows, reducing total energy demand.
Activity Levels and Respiration: Individuals with high physical activity levels require a greater caloric intake of carbohydrates to fuel the increased rate of muscular contraction and aerobic respiration. Metabolic demand scales directly with the intensity and duration of physical exertion.
Pregnancy and Lactation: During pregnancy, energy requirements increase to support fetal development and the additional maternal mass. Similarly, breastfeeding mothers require extra energy and calcium to produce nutrient-rich breast milk without depleting their own bodily reserves.
| Feature | Macronutrients | Micronutrients |
|---|---|---|
| Quantity Needed | Grams (large) | Milligrams/Micrograms (small) |
| Primary Function | Energy & Structure | Co-factors & Regulation |
| Examples | Proteins, Lipids | Iron, Vitamin C |
Identify Deficiency Correlations: Exams often ask to link a specific symptom to a nutrient. Always remember the logical chain: Nutrient Biological Function Deficiency Symptom. For example, Iron Haemoglobin Fatigue.
Energy Demand Variables: When analyzing energy needs, always check for Age, Activity, and Reproductive Status (Pregnancy). These are the three primary factors used to explain why two individuals have different caloric requirements.
Precise Definitions: Ensure you define a 'balanced diet' by mentioning 'all food groups' and 'correct proportions'. Missing either term often results in partial marks.
Sanity Check for Sources: When listing food sources, prioritize general groups. For example, cite 'citrus fruits' for Vitamin C rather than just 'an orange' to demonstrate broader botanical knowledge.
