Deficiency Disorders
~7 min read
- Vitamin: A — Night blindness; B₁ — Beriberi; C — Scurvy; D — Rickets; K — Bleeding.
- Protein: Kwashiorkor (protein deficient diet); Marasmus (calorie + protein).
- Mineral: Iron — Anaemia; Iodine — Goitre; Fluoride — Dental caries; Calcium — Tetany.
Deficiency disorders link specific nutrients to specific diseases — a CDS/OTA staple with predictable patterns.
Vitamin Deficiencies
| Vitamin | Chemical name | Deficiency disease |
|---|---|---|
| A | Retinol | Night blindness, xerophthalmia |
| B₁ | Thiamine | Beriberi |
| B₂ | Riboflavin | Cheilosis, glossitis |
| B₃ | Niacin | Pellagra (3 D's: dermatitis, diarrhoea, dementia) |
| B₁₂ | Cobalamin | Pernicious anaemia |
| C | Ascorbic acid | Scurvy — bleeding gums, falling teeth, fragile bones, delayed wound healing |
| D | Calciferol | Rickets (children), Osteomalacia (adults) |
| E | Tocopherol | Sterility (in animal studies) |
| K | Phylloquinone | Defective blood clotting |
Protein-Energy Malnutrition
- Kwashiorkor: caused by sufficient carbohydrates and fats but deficient proteins. Common in young children weaned to starchy diets. Signs: pot belly (oedema), thin hair, irritability.
- Marasmus: deficiency of both proteins and calories. The child is severely underweight, all body fat lost.
- Both reflect the broader problem of malnutrition. India runs Mid-Day Meal and ICDS programmes to combat it.
Mineral Deficiencies
| Mineral | Deficiency disease |
|---|---|
| Iron (Fe) | Anaemia — low haemoglobin |
| Iodine (I) | Goitre, cretinism (iodised salt prevents both) |
| Calcium (Ca) | Tetany, weak bones |
| Fluoride (F) | Tooth caries (deficit); Mottling of teeth and fluorosis (excess) |
| Sodium | Hyponatraemia — cramps, confusion |
Radioactive Substances in Food Chain
- Strontium-90, Iodine-131, Cesium-137 can enter the body through the food chain and cause physiological disorders.
- Strontium mimics calcium and lodges in bones; iodine-131 concentrates in thyroid causing cancer; cesium spreads through soft tissues.
- This is the danger of nuclear fallout — long-lived isotopes in soil contaminate crops for decades.
CDS/OTA PYQ Examples
Q: Vitamin-disease pairs: 1. Vit A — Rickets; 2. Vit B₁ — Beriberi; 3. Vit C — Scurvy. Which are correctly matched?
(a) 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3
Answer: (b) 2 and 3 — Vitamin A deficiency causes night blindness, not rickets (which is Vitamin D). [CDS-I 2016]
Q: Deficiency of fluoride leads to:
(a) Tooth caries (b) Mottling of tooth (c) Bending of bones (d) Stiffening of joints
Answer: (a) Tooth caries — fluoride strengthens enamel. [CDS-II 2016]
Q: Bleeding of gums, fragile bones and delayed wound healing occur due to deficiency of:
(a) Vitamin C (b) Vitamin K (c) Vitamin D (d) Vitamin B
Answer: (a) Vitamin C — scurvy. [CDS-I 2017]
Q: Kwashiorkor in children is caused by:
(a) Sufficient carbohydrates but less fats (b) Sufficient carbohydrates and fats but deficient proteins (c) Sufficient vitamins but deficient fats (d) Sufficient fats but deficient vitamins
Answer: (b) Deficiency of protein in an otherwise adequate-calorie diet. [CDS-I 2017]
Q: Rickets develops in children due to deficiency of:
(a) Vitamin C (b) Vitamin D (c) Vitamin A (d) Vitamin B
Answer: (b) Vitamin D — needed for calcium absorption. [CDS-I 2022]
Q: Deficiency of iron causes:
(a) Anaemia (b) Scurvy (c) Rickets (d) Cholera
Answer: (a) Anaemia. [CDS-II 2022]
Drill Deficiency Disorders for CDS/OTA
CDS/OTA-pattern items on Deficiency Disorders with answer keys and explanations.
Start Free Mock TestFrequently Asked Questions
Why is iodised salt important?
Iodine is needed to make thyroxine. Deficiency causes goitre (enlarged thyroid) in adults and cretinism (stunted growth, mental retardation) in children. Iodised salt has prevented millions of cases.
How does rickets actually develop?
Vitamin D enables calcium absorption from food. Without it, bones can't mineralise and become soft, leading to bow legs and skull deformities in children.
Why is sunlight important for Vitamin D?
UV-B in sunlight converts a cholesterol derivative in skin to vitamin D₃ (cholecalciferol). 15–20 min daily exposure provides most of what the body needs.