BiologyICSE Class 9 · Nutrition and the Digestive System

Vitamins, Balanced Diet and Malnutrition (ICSE Class 9 Biology)

Updated 17 October 2026 · Fact-checked

Food contains carbohydrates, proteins, fats, vitamins, minerals, water and roughage. Vitamins are needed in small amounts, and a lack causes deficiency diseases such as night blindness (A), scurvy (C) and rickets (D). A balanced diet has all nutrients in the right proportion; protein deficiency causes kwashiorkor and marasmus.

Match each vitamin to its disease when it is missing: A with night blindness, C with scurvy, D with rickets; lack of protein causes kwashiorkor, and lack of foo

Illustration drawn for QuestionBuddy.

Understand Vitamins, Balanced Diet and Malnutrition

1. Classes of food. *Carbohydrates* give energy (1 g gives about 17 kJ); *fats* give concentrated energy and insulation; *proteins* build and repair the body; *vitamins* and *minerals* regulate body processes; *water* is the medium for reactions; *roughage* (dietary fibre) prevents constipation.

2. Vitamins.

*A (retinol)*: carrots, liver, milk; vision. Deficiency: night blindness, xerophthalmia.
*B complex*: whole grains, pulses, yeast; B1 deficiency causes beriberi.
*C (ascorbic acid)*: citrus fruits, amla; scurvy (bleeding gums).
*D*: sunlight, fish liver oil, eggs; helps absorb calcium; rickets in children, osteomalacia in adults.
*E*: vegetable oils, nuts; protects cells.
*K*: green vegetables; blood clotting; deficiency causes excess bleeding.

Vitamins A, D, E and K are fat-soluble; B and C are water-soluble.

3. Balanced diet. It supplies all nutrients, adequate water and roughage in proportion to age, sex, activity and health. A growing child, a pregnant woman and a heavy worker need more.

4. Malnutrition. Poor diet. *Kwashiorkor*: lack of protein with enough calories; swollen belly and swollen (oedematous) face, feet and legs, thin wasted muscles, skin and hair changes. *Marasmus*: lack of both calories and protein; severe wasting, a very thin body. Both are seen mostly in children.

Vitamins, Balanced Diet and Malnutrition: key facts

Fat soluble: $A ∣ D ∣ E ∣ K$
Deficiency: A: night blindness
B1: beriberi
C: scurvy
D: rickets
K: poor clotting
Malnutrition: Kwashiorkor: protein deficiency, swollen body | Marasmus: lack of food energy, wasting
Food roles: Carbohydrate energy
Protein growth
Fat reserve
Roughage bowel movement

Carbohydrate	energy
Protein	growth
Fat	reserve
Roughage	bowel movement

Vitamins, Balanced Diet and Malnutrition in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Planning a school lunch box

Suppose a student eats only rice and potatoes for lunch every day and feels tired with bleeding gums.

Suggest changes.

Try it first, then show the solutionSolution

Rice and potato give mainly carbohydrate.
Bleeding gums suggest a lack of vitamin C.
Add pulses for protein and citrus fruits or amla.

Answer: Add pulses, vegetables and citrus fruit.

Memory hook: Colourful plate.

Tricks to remember Vitamins, Balanced Diet and Malnutrition

Short memory aids. Say each one aloud once, then use it on a question the same day.

ADEK in fat
A, D, E, K dissolve in fat.
Use it when: Vitamin solubility.
C scurvy
C for gums: scurvy.
Use it when: Vitamin C.

Vitamins, Balanced Diet and Malnutrition: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Match · 3 marks · Short answerBoard level

Name the deficiency disease of vitamins (a) A, (b) C, (c) D. [3]

Try it first, then show the solutionSolution

(a) Night blindness.
(b) Scurvy.
(c) Rickets.

Answer: (a) Night blindness (b) Scurvy (c) Rickets.

Example 2: Kwashiorkor vs marasmus · 3 marks · Short answerHarder board level

Give three differences between kwashiorkor and marasmus. [3]

Try it first, then show the solutionSolution

Cause: protein lack versus lack of overall food.
Body: swollen belly versus severe wasting.
Calories: adequate versus very low.

Answer: Kwashiorkor: protein deficiency with enough calories, swollen belly and limbs. Marasmus: deficiency of both calories and protein, severe wasting.

Example 3: Why sunlight · 3 marks · Short answerHarder board level

Why do children living indoors with little sunshine develop rickets? [3]

Try it first, then show the solutionSolution

Sunlight helps the skin make vitamin D.
Vitamin D helps absorb calcium.
Without it the bones become soft and bent.

Answer: Less sunlight means less vitamin D, calcium absorption falls and bones soften.

Example 4: Diet table · 3 marks · Short answerHarder board level

A diet gives 60 g carbohydrate, 15 g protein and 10 g fat. Estimate the energy if 1 g of carbohydrate or protein gives 17 kJ and 1 g of fat gives 37 kJ. [3]

Try it first, then show the solutionSolution

Carbohydrate: 60 x 17 = 1020 kJ.
Protein: 15 x 17 = 255 kJ.
Fat: 10 x 37 = 370 kJ. Total = 1645 kJ.

Answer: 1020 + 255 + 370 = 1645 kJ. (Energy values are assumed standard figures.)

Example 5: Case: the hostel · 5 marks · Case-basedHOTS / competency

Case. A hostel gives only polished rice and boiled potatoes for months, and students show weakness and tingling in the legs. (i) Name the vitamin lacking and the disease. [2] (ii) Which food would help? [1] (iii) Why does polishing rice cause the problem? [2]

Try it first, then show the solutionSolution

(i) B1; beriberi.
(ii) Whole grains, pulses or yeast.
(iii) Polishing removes the bran (outer layer) of the grain, which holds vitamin B1.

Answer: (i) Vitamin B1; beriberi (ii) Whole grains (iii) Polishing removes the vitamin-rich outer layer.

Where students lose marks in Vitamins, Balanced Diet and Malnutrition

The slips examiners see most often, and what to write instead.

Mistake: Writing that vitamins give energy
Confusion with carbohydrates.
Do this: Vitamins regulate; they do not provide energy.
Usually costs: 1 mark.
Mistake: Saying scurvy is caused by lack of D
Letters are mixed.
Do this: C: scurvy; D: rickets.
Usually costs: 1 mark.
Mistake: Forgetting units in energy sums
Units omitted.
Do this: Write kJ with every step.
Usually costs: 1 mark.

Exam tips

Memorise vitamin, source and deficiency as one row.
Show working in energy questions.
Distinguish protein deficiency from calorie deficiency.
Mention age and activity in balanced diet answers.

Practice questions on Vitamins, Balanced Diet and Malnutrition

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Which vitamin is needed for blood clotting?
(a) A
(b) C
(c) K
(d) D
Hint
K for Koagulation.
Answer
(c) K.
Q2 · 2 marks · Very short answerBoard level
Name two sources of vitamin C. [2]
Hint
Citrus.
Answer
Orange (citrus fruits) and amla.
Q3 · 2 marks · Very short answerBoard level
Why is roughage necessary although it is not digested? [2]
Hint
Fibre.
Answer
It adds bulk and helps the movement of food and prevents constipation.
Q4 · 1 mark · Assertion-reasonHarder board level
Assertion (A): A pregnant woman needs extra protein in her diet.
Reason (R): The growing baby needs materials for body building.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Growth.
Answer
(a).
Q5 · 2 marks · Very short answerHarder board level
Explain why night blindness occurs in vitamin A deficiency. [2]
Hint
Vision.
Answer
Vitamin A is needed for the pigment in the eye that works in dim light.
Q6 · 3 marks · Short answerBoard level
Differentiate between fat-soluble and water-soluble vitamins with two examples each. [3]
Hint
Storage.
Answer
Fat-soluble vitamins (A and D) are stored in the body; water-soluble ones (B and C) are not stored and are needed regularly.
Q7 · 3 marks · Short answerHarder board level
A diet is rich in energy but poor in protein. Predict the likely disease in a child and give two signs. [3]
Hint
Swelling.
Answer
Kwashiorkor; swollen belly and oedema (swollen face, feet and legs), and skin or hair changes.
Q8 · 3 marks · Short answerHarder board level
Why are cooking practices that boil vegetables for long hours harmful to vitamin C? Suggest an alternative. [3]
Hint
Heat.
Answer
Vitamin C is water-soluble and destroyed by heat, so it is lost; steam or lightly cook, and eat some fruits raw.
Q9 · 4 marks · Case-basedHOTS / competency
Case. A girl eats a diet rich in fruit and vegetables but never takes milk or goes in the sun and has weak bones. (i) Name the vitamin and mineral involved. [2] (ii) Give two remedies. [2]
Hint
D and calcium.
Answer
(i) Vitamin D and calcium. (ii) Take milk or fish and spend time in sunlight.
Q10 · 4 marks · Case-basedHOTS / competency
Case. Two children: A has a swollen belly and swollen feet; B is extremely thin with visible ribs. (i) Name each condition. [2] (ii) Which is due to a severe overall shortage of food (calories and protein)? [1] (iii) Suggest a treatment. [1]
Hint
Compare.
Answer
(i) A: kwashiorkor; B: marasmus. (ii) Marasmus. (iii) A balanced diet rich in protein under medical advice.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Vitamin for night vision?Show answer
A.
2.Disease of vitamin C lack?Show answer
Scurvy.
3.Fat soluble vitamins?Show answer
A, D, E, K.
4.Marasmus is due to?Show answer
Lack of food energy and protein.
5.Roughage is?Show answer
Dietary fibre.

Vitamins, Balanced Diet and Malnutrition: frequently asked questions

Can we make any vitamin?

Skin makes vitamin D with sunlight.

What is malnutrition?

A diet lacking or excess in nutrients.

Is water a food?

Water is essential though not a source of energy.