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What are deficiency diseases? Give examples.

Class 6 ScienceNCERT chapter: Mindful Eating: A Path to a Healthy Bodyइसे हिंदी में पढ़ें

Exam-ready answer

Deficiency diseases are diseases caused by a lack of one or more nutrients in the diet over a long period. Examples are night blindness (vitamin A), beriberi (vitamin B1), scurvy (vitamin C), rickets (vitamin D), anaemia (iron) and goitre (iodine). They can be prevented by eating a balanced diet that includes a variety of foods.

Explanation

Each nutrient does a particular job in the body. When a person's diet lacks a nutrient for a long time, the body cannot carry out that job properly and shows certain symptoms. A disease caused in this way is called a deficiency disease. It is not caught from another person; it develops because of what is missing from the diet.

Lack of vitamin A causes poor vision, especially night blindness. Lack of vitamin B1 causes beriberi, with weak muscles and very little energy. Lack of vitamin C causes scurvy, in which gums bleed and wounds heal slowly. Lack of vitamin D causes rickets, in which bones become soft and bent. Lack of iron causes anaemia, with tiredness, and lack of iodine causes goitre, a swelling in the neck.

Most of these diseases can be prevented by eating a balanced diet. Green leafy vegetables, carrots, milk, citrus fruits like amla and lemon, whole grains, pulses and iodised salt supply these nutrients. The skin also makes vitamin D in sunlight. A person who shows signs of a deficiency should see a doctor, who decides the right treatment.

Points to remember

  1. Deficiency disease: a disease caused by the lack of a nutrient in the diet over a long period.
  2. Vitamin A: night blindness; vitamin B1: beriberi; vitamin C: scurvy; vitamin D: rickets.
  3. Iron deficiency causes anaemia; iodine deficiency causes goitre.
  4. Deficiency diseases are not passed from one person to another.
  5. They can be prevented by a balanced diet; iodised salt helps prevent goitre.

Exam tip

Give the definition first, then a neat table with three columns: nutrient, deficiency disease and symptoms. Match each vitamin with the correct disease carefully, as this is often asked as a matching question.

Questions students also ask

Are deficiency diseases infectious?
No. Deficiency diseases do not spread from one person to another through air, water or touch. They are caused by a lack of nutrients in a person's own diet over a long time, so they can be prevented by improving the diet.
Why is iodised salt recommended?
Iodine is a mineral the body needs in small amounts, and its lack causes goitre, a swelling of the neck. Common salt is used daily by almost everyone, so adding iodine to it is an easy way to make sure people get enough iodine.
Which foods help prevent anaemia?
Anaemia is often caused by too little iron. Foods rich in iron include green leafy vegetables such as spinach, jaggery, pulses, amla and other fruits. Anyone who feels very tired or looks pale for a long time should see a doctor.

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