Deficiency
Comprehensive notes, formulas, and practice questions for Deficiency.
Deficiency
Deficiency Diseases
What you'll learn
- Deficiency diseases caused by lack of specific nutrients over time.
- Key examples — Vitamin A (night blindness), Vitamin C (scurvy), Vitamin D (rickets), iron (anaemia), iodine (goitre).
- How balanced diet and fortified foods (iodised salt) prevent deficiencies.
- Difference between malnutrition (undernutrition) and overnutrition (obesity intro).
Key concepts
Level 1 — Nutrient → deficiency link
Verbal: When the body does not get enough of a vitamin or mineral for long periods, specific deficiency diseases appear.
| Deficiency | Disease / symptom | Rich food sources |
|---|---|---|
| Vitamin A | Night blindness, dry eyes | Carrot, papaya, milk, green leafy vegetables |
| Vitamin C | Scurvy (bleeding gums) | Amla, citrus fruits, guava |
| Vitamin D | Rickets (soft bones) | Sunlight, milk, fish |
| Iron | Anaemia (weakness, pale) | Spinach, jaggery, liver, pulses |
| Iodine | Goitre (swollen neck) | Iodised salt, seafood |
Visual: Long-term lack → body cannot perform function → visible symptoms.
Level 2 — Prevention and public health
Balanced diet: Primary prevention — include fruits, vegetables, pulses daily.
Fortification: Iodised salt prevents goitre at population level (India's salt iodisation programme).
Sunlight: Body makes Vitamin D when skin exposed to morning sun — important for bone strength.
Protein-energy malnutrition (intro): Kwashiorkor and marasmus in severe undernutrition — need medical care and proper food.
Obesity (overnutrition): Excess fats and sugars → weight gain, linked to lifestyle diseases later.
Worked example
A child eats mostly polished rice and tea, avoids vegetables. Predict possible deficiencies.
Step 1 — Low iron & Vitamin A from missing greens → risk of anaemia, poor vision in dim light
Step 2 — Low Vitamin C → weak gums if no fruits
Step 3 — Low protein if no dal/milk/egg → poor growth
Step 4 — Prevention: add dal, seasonal vegetables, fruit, iodised salt
Common mistakes
| Mistake | Why it happens | Fix |
|---|---|---|
| All weakness = lack of sleep only | Ignoring anaemia | Pale skin + tiredness may signal iron deficiency |
| Carrots alone cure everything | Oversimplified advice | Vitamin A helps vision but diet needs balance |
| Goitre only in mountains | Iodine myth | Can occur anywhere without iodised salt |
| Vitamin pills replace meals | Supplement hype | Whole foods provide multiple nutrients together |
Quick check
- Which vitamin deficiency causes night blindness?
- Name the disease caused by lack of Vitamin C.
- Why is iodised salt used in households?
- How does sunlight help prevent rickets?
Open the Practice tab for graded questions on Deficiency Diseases.
Key Takeaways (TL;DR)
- What you'll learn
- Key concepts
- Worked example
- Common mistakes
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