According to the World Health Organisation (WHO), health is defined as:

Health is a state of complete physical, mental, and social well being and not merely absence of disease or infirmity.

Disease

Disease is a malfunctioning process related to a certain part of the whole body in which normal functions are disturbed or damaged. Disease literally means not at ease (dis = not)

Deficiency Diseases

The diseases which occur due to deficiency of one or more nutrients (proteins,carbohydrates, vitamins and minerals) in our diet are called deficiency diseases.

Malnutrition: The condition resulting from lack of nutrients in the diet is called malnutrition. Malnutrition affects the health of the children adversely as it results in physical and mental retardation.

The deficiency diseases are of three types:

  1. Protein Energy Malnutrition (PEM)
  2. Mineral deficiency diseases
  3. Vitamin deficiency diseases