Which vitamin is produced by the body when exposed to sunlight?

Vitamin D (Calciferol) is produced by the skin when exposed to sunlight (UV rays). Its deficiency causes Rickets in children (soft, deformed bones) and Osteomalacia in adults.

What is the difference between communicable and non-communicable diseases?

Communicable (infectious) diseases spread from person to person through pathogens — bacteria, viruses, parasites (e.g., tuberculosis, malaria, COVID-19). Non-communicable diseases (NCDs) do not spread and are caused by lifestyle, genetics, or environment (e.g., diabetes, heart disease, cancer).

Which mosquito spreads malaria and dengue?

Malaria is spread by the female Anopheles mosquito (Plasmodium parasite). Dengue is spread by the Aedes aegypti mosquito (dengue virus). Both require standing water to breed.

BMI (Body Mass Index) = Weight (kg) ÷ Height² (m²). Normal BMI = 18.5–24.9. Below 18.5 = Underweight. 25–29.9 = Overweight. 30+ = Obese.

Health, Nutrition and Diseases — TNPSC Group 4 Science Notes

Overview

Health and nutrition is a consistently high-scoring area in TNPSC Group 4 science. Questions typically cover vitamins and their deficiency diseases, communicable vs non-communicable diseases, mosquito-borne diseases, vaccines, and government health schemes. Memorise the vitamin table — it appears almost every year.

Nutrients and Their Functions

Macronutrients (needed in large amounts)

Nutrient	Functions	Sources
Carbohydrates	Primary energy source (4 kcal/g)	Rice, wheat, potato, sugar
Proteins	Growth, repair, enzymes, antibodies (4 kcal/g)	Pulses, meat, egg, milk, soy
Fats	Energy storage (9 kcal/g); fat-soluble vitamins	Ghee, oil, nuts, butter
Water	Transport, temperature regulation	Drinking water, fruits
Dietary Fibre	Digestive health; prevents constipation	Vegetables, whole grains

Vitamins

Vitamins are micronutrients needed in small amounts. They are organic compounds that the body cannot make in sufficient quantities.

Fat-Soluble Vitamins (A, D, E, K)

Stored in body fat and liver — excess can be toxic.

Vitamin	Chemical Name	Deficiency Disease	Sources
A	Retinol	Night blindness; Xerophthalmia (dry eyes)	Carrot, sweet potato, liver, egg yolk
D	Calciferol	Rickets (children), Osteomalacia (adults)	Sunlight, fish liver oil, fortified milk
E	Tocopherol	Anaemia in premature babies; infertility	Nuts, seeds, vegetable oils
K	Phylloquinone	Excessive bleeding; poor blood clotting	Green leafy vegetables, broccoli

Water-Soluble Vitamins (B complex, C)

Not stored — must be consumed daily; excess excreted.

Vitamin	Chemical Name	Deficiency Disease	Sources
B1	Thiamine	Beriberi (nerve and heart damage)	Whole grains, legumes
B2	Riboflavin	Ariboflavinosis (cracked lips, sore throat)	Milk, meat, eggs
B3	Niacin	Pellagra (4Ds: Dermatitis, Diarrhoea, Dementia, Death)	Meat, peanuts, whole grains
B6	Pyridoxine	Anaemia, nerve damage	Poultry, fish, potatoes
B9	Folic Acid	Neural tube defects in foetus; megaloblastic anaemia	Green leafy vegetables, legumes
B12	Cobalamin	Pernicious anaemia; nerve damage	Meat, dairy, eggs (not in plants)
C	Ascorbic acid	Scurvy (bleeding gums, slow healing)	Citrus fruits, amla, guava

TNPSC Memory Trick: - Night blindness → A - Beriberi → B1 - Rickets → D (sunDight) - Scurvy → C

Minerals

Mineral	Function	Deficiency	Sources
Calcium	Bones, teeth, blood clotting	Osteoporosis, weak bones	Milk, dairy, ragi
Iron	Haemoglobin (carries oxygen)	Iron-deficiency anaemia	Spinach, liver, jaggery
Iodine	Thyroid hormone	Goitre (swollen thyroid gland)	Iodised salt, seafood
Phosphorus	Bones, teeth, DNA	Weakness	Dairy, meat, nuts
Potassium	Nerve and muscle function	Muscle weakness	Banana, potato
Fluoride	Tooth enamel	Dental cavities	Fluoridated water, tea
Sodium	Fluid balance, nerve function	Hyponatraemia (muscle cramps)	Salt
Zinc	Immune system, wound healing	Growth retardation	Meat, nuts, whole grains

Communicable (Infectious) Diseases

Bacterial Diseases

Disease	Bacteria	Spread	Key Facts
Tuberculosis (TB)	Mycobacterium tuberculosis	Airborne (coughing)	BCG vaccine; affects lungs mainly
Cholera	Vibrio cholerae	Contaminated water/food	Severe diarrhoea; ORS treatment
Typhoid	Salmonella typhi	Contaminated water/food	High fever; TAB vaccine
Leprosy	Mycobacterium leprae	Prolonged close contact	Affects skin and nerves; curable
Plague	Yersinia pestis	Flea bite (from rats)	Bubonic plague; historical epidemics
Tetanus	Clostridium tetani	Wound infection	Lockjaw; DPT vaccine

Viral Diseases

Disease	Virus	Spread	Key Facts
Polio	Poliovirus	Oral-faecal route	OPV (oral) and IPV vaccines; India polio-free since 2014
Measles	Paramyxovirus	Airborne	MMR vaccine
Rabies	Rhabdovirus	Animal (dog/bat) bite	Always fatal once symptoms appear; post-exposure vaccine works
Dengue	Dengue virus	Aedes aegypti mosquito	No specific antiviral; manage fever, fluids
Hepatitis B	HBV	Blood, sexual contact	HBV vaccine; can cause liver cancer
HIV/AIDS	HIV	Blood, sexual contact, mother to child	No cure; antiretroviral therapy (ART)
Influenza	Influenza virus	Airborne	Annual flu vaccine

Parasitic/Protozoan Diseases

Disease	Parasite	Vector	Key Facts
Malaria	Plasmodium (4 species)	Female Anopheles mosquito	P. falciparum most dangerous; chloroquine treatment
Filariasis (Elephantiasis)	Wuchereria bancrofti	Culex mosquito	Swelling of limbs
Kala-azar (Leishmaniasis)	Leishmania	Sandfly bite	Affects liver, spleen
Amoebiasis	Entamoeba histolytica	Contaminated water	Amoebic dysentery

Non-Communicable Diseases (NCDs)

Disease	Cause	Key Facts
Diabetes Mellitus	Insulin deficiency/resistance	Type 1 (childhood onset), Type 2 (lifestyle); India is "diabetes capital of the world"
Hypertension	High blood pressure	Normal BP = 120/80 mmHg; increases risk of heart attack, stroke
Cardiovascular Disease	Lifestyle, genetics	Leading cause of death in India; atherosclerosis (artery blockage)
Cancer	Abnormal cell growth	Carcinogens (tobacco, radiation); common types: oral, lung, breast, cervical
Asthma	Inflammation of airways	Allergens, pollution trigger attacks
Obesity	Excess body fat (BMI > 30)	Increases risk of diabetes, heart disease

Vaccines and Immunisation

Universal Immunisation Programme (UIP) — India

Vaccine	Disease Protected	Route
BCG	Tuberculosis	Intradermal
OPV / IPV	Polio	Oral / Injection
DPT	Diphtheria, Pertussis, Tetanus	Injection
Hepatitis B	Hepatitis B	Injection
MMR	Measles, Mumps, Rubella	Injection
JE vaccine	Japanese Encephalitis	Injection

TNPSC Tip: Edward Jenner developed the first smallpox vaccine (1796) — the first vaccine in history. Smallpox was eradicated globally in 1980.

Types of Immunity

Type	Description
Innate	Born with it; non-specific (skin, mucus)
Acquired Active	Body makes antibodies after infection or vaccination
Acquired Passive	Antibodies received from mother (breast milk) or injection

Important Health Indicators

Indicator	India (Approximate)
Life expectancy	~70 years
Infant Mortality Rate (IMR)	~28 per 1,000 live births
Maternal Mortality Rate (MMR)	~97 per 1,00,000 live births
Total Fertility Rate (TFR)	~2.0

Government Health Programmes

Programme	Purpose
National Health Mission (NHM)	Rural + urban health infrastructure
Ayushman Bharat (PM-JAY)	Health insurance ₹5 lakh/family for poor
Pulse Polio Programme	Eradicate polio
National TB Elimination Programme	Eliminate TB by 2025
RNTCP	Revised National TB Control Programme
DOTS	Directly Observed Treatment Short-course (TB)
Mission Indradhanush	Full immunisation for children

Previous Year TNPSC Questions (Pattern)

1. Q: Deficiency of Vitamin C causes → Scurvy 2. Q: Malaria is caused by → Plasmodium (spread by Anopheles mosquito) 3. Q: Goitre is caused by deficiency of → Iodine 4. Q: Which vaccine is given at birth? → BCG (and Hepatitis B, OPV) 5. Q: Smallpox vaccine was discovered by → Edward Jenner 6. Q: Night blindness is caused by deficiency of → Vitamin A 7. Q: Dengue is transmitted by → Aedes aegypti mosquito 8. Q: Beriberi is caused by deficiency of → Vitamin B1 (Thiamine)

Frequently Asked Questions

Scurvy is caused by Vitamin C (Ascorbic acid) deficiency. Symptoms include bleeding gums, slow wound healing, and joint pain. Found in citrus fruits, amla, and guava.