7.1 Diet & Nutrients
The 7 Essential Nutrients for Human Health
🎯 Examiner Focus: A balanced diet contains all 7 nutrients in the correct proportions for the individual's needs. Know the specific deficiency diseases: Scurvy (Vitamin C) and Rickets (Vitamin D).
The 7 Essential Nutrients
🍚 Carbohydrates
Function: Main source of energy
Sources: Rice, Potatoes, Bread, Pasta
🔬 Biochemistry: Broken down into glucose during digestion for cellular respiration
🧈 Fats (Lipids)
Function: Energy storage, insulation, protection of organs
Sources: Butter, Oil, Nuts, Avocado
⚠️ Excess Risk: Too much fat → Obesity → Coronary Heart Disease
🥩 Proteins
Function: Growth and repair of tissues
Sources: Meat, Fish, Eggs, Beans
🔬 Structure: Made of amino acids - the building blocks of life
🍊 Vitamin C
Function: Healthy skin, gums, and blood vessels
Sources: Citrus fruits (oranges, lemons), tomatoes
⚠️ Deficiency: SCURVY - bleeding gums, easy bruising
☀️ Vitamin D
Function: Strong bones and teeth (helps absorb calcium)
Sources: Sunlight (skin synthesis), Milk, Eggs
⚠️ Deficiency: RICKETS (children) - soft, bowed bones
🦴 Calcium
Function: Strong bones and teeth, blood clotting
Sources: Milk, Cheese, Yogurt, Leafy greens
🔬 Partners: Works with Vitamin D for bone health
🩸 Iron
Function: Makes haemoglobin in red blood cells
Sources: Red meat, Spinach, Liver
⚠️ Deficiency: ANEMIA - tiredness, pale skin, breathlessness
🥦 Fibre
Function: Aids peristalsis (gut movement), prevents constipation
Sources: Vegetables, Whole grains, Fruits
🔬 Note: Not digested but essential for gut health
💧 Water
Function: Solvent for chemical reactions, transport medium
Sources: Drinking water, Fruits, Vegetables
🔬 Essential: 60-70% of body mass is water
🎯 What is a "Balanced Diet"?
A balanced diet contains all 7 nutrients in the correct proportions for the individual's age, sex, activity level, and health status.
Cambridge IGCSE Learning Objectives
- ✓ Define a balanced diet as containing all 7 nutrients in correct proportions
- ✓ Identify sources and functions of: Carbohydrates, Fats, Proteins, Vitamin C, Vitamin D, Calcium, Iron, Fibre, Water
- ✓ Describe deficiency diseases: Scurvy (Vitamin C), Rickets (Vitamin D), Anemia (Iron)
- ✓ Explain why excess fat consumption increases risk of Coronary Heart Disease
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