TEACHGYAN • CLASS 8 SCIENCE • CURIOSITY
Chapter 3: Health: The Ultimate Treasure
Health • Nutrition • Disease • Prevention • Community well-being
❤️ 1. Is Health Only the Absence of Disease?
Being healthy is broader than simply “not being sick”. Health includes physical well-being and also mental and social dimensions. A person’s surroundings, nutrition, hygiene, activity, rest and access to health services can influence health.
nutrition • activity • rest
emotional well-being • coping
relationships • safe community
🥗 2. Balanced Nutrition
The body needs different nutrients for energy, growth, repair and regulation. A balanced diet is not a single “perfect food”; it is a suitable combination and quantity of foods that supplies essential nutrients, water and fibre.
| Nutrient | Main role | Common sources |
|---|---|---|
| Carbohydrates | Major energy source | Rice, wheat, potatoes |
| Proteins | Growth and repair | Dal, beans, milk, eggs |
| Fats | Energy and other body functions | Nuts, seeds, oils |
| Vitamins & minerals | Support body processes | Fruits, vegetables, varied foods |
| Water | Essential for body processes | Water and water-rich foods |
| Fibre | Supports healthy digestion | Whole grains, fruits, vegetables |
🧩 3. Nutrient Deficiency
If the body does not receive enough of an essential nutrient over time, deficiency problems can develop. For example, vitamin C deficiency can cause scurvy and vitamin D deficiency can contribute to rickets. The key idea is to connect the condition with the nutrient and understand prevention through adequate nutrition.
🦠 4. Communicable vs Non-Communicable Diseases
| Communicable | Non-communicable |
|---|---|
| Can spread through infectious agents or routes of transmission. | Do not spread directly from one person to another. |
| Examples may include influenza or some diarrhoeal infections. | Examples include many forms of diabetes and hypertension. |
| Prevention includes hygiene, safe water, vaccination where appropriate and reducing exposure. | Risk may be influenced by genetics, lifestyle and environment. |
🛡️ 5. Prevention Is a Chain
🧠 Concept MCQs
- Health includes: A) only absence of fever B) physical, mental and social well-being C) only body weight D) only exercise
- Proteins are especially important for: A) growth and repair B) only thirst C) only vision D) only digestion
- A communicable disease can: A) never spread B) spread through infectious agents and routes of transmission C) always be inherited D) always be caused by diet
- Which is a preventive public-health measure? A) unsafe water B) handwashing C) sharing contaminated food D) ignoring symptoms
Answers: 1-B, 2-A, 3-B, 4-B.
📌 Case Study
A school notices that several students have repeated stomach infections. Investigation shows that some students drink untreated water and food is sometimes left uncovered.
- Which factors may contribute to transmission?
- Which observations or evidence should the school collect?
- Suggest practical preventive measures.
- Why is community cooperation important?
🔥 HOTS
- Explain why a person can be free from an infectious disease and still have poor health.
- Why is “eat more of one nutrient” not the same as having a balanced diet?
- Design a one-week school health-awareness plan based on prevention.
✍️ Exam Practice
- Explain the broad meaning of health.
- What is a balanced diet? Why is variety important?
- Differentiate communicable and non-communicable diseases.
- Explain two ways to prevent infectious disease transmission.
- Explain deficiency disease with one example.
🎯 Quick Revision Map
Health → Nutrition → Body functions → Disease → Transmission/Risk → Prevention → Community well-being.
🏆 Mastery Checklist
- ☐ I can explain health beyond absence of disease.
- ☐ I can explain nutrient functions.
- ☐ I can identify deficiency examples.
- ☐ I can distinguish communicable and non-communicable diseases.
- ☐ I can suggest evidence-based preventive measures.