Page 27 - Biology Form Two

Biology for Secondary Schools

diarrhoea, anaemia, dry skin that cracks Nutritional disorders
easily, oedema due to accumulation of Nutritional disorders are conditions
excess fluid in the body, and short temper. that occur when a person’s dietary

Prevention of kwashiorkor: intake does not contain the right amount
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Kwashiorkor can be prevented by of nutrients for healthy functioning
providing a child with a diet that has of the body. They are caused by the
adequate amounts of protein and other imbalance of nutrients in the body
due to not having enough nutrients
food nutrients. or excess consumption of food. The
Rickets common nutritional disorders include
Rickets is a condition whereby the bones obesity, anorexia nervosa, and bulimia

of a child soften, leading to fractures nervosa.
and deformity. A lack of vitamin D,
phosphorus and calcium causes rickets. Obesity
Obesity is a nutritional disorder
Symptoms of rickets: A child suffering characterised by excess body fat leading
from rickets can be identified by to overweight. It mostly results from
observable skeletal deformities such as eating large quantities of high energy

bow legs, knock knees, an odd-shaped foods (carbohydrates and fats) and not
skull, and a deformed spine. The child exercising enough to sufficiently burn
feels bone pain, experiences dental the excess calories produced in the body.
problems such as weak teeth or delayed A person’s sex, age and level of activity
formation of teeth, and develops weak are among other factors that determine
muscles. The child’s bones can easily his or her ideal body fat. To maintain
be fractured and shows slow growth. fertility, women need more body fat than
The child also gets muscle spasms and men. Women also store more fat in their
muscle cramps. breasts, hips and thighs.

Body weight and health risks associated
Prevention of rickets: Rickets can be
prevented by increasing the amount of with it are expressed by the Body Mass
Index (BMI). It gives the relationship
vitamin D, phosphorus and calcium between the estimated body fat and the
in the diet. The condition can also be risk of certain diseases or conditions.
prevented by ensuring exposure to Based on height and weight ratio, people
sufficient amounts of sunlight, and can check their Body Mass Index (BMI).
providing the child with enough milk, The BMI is calculated by dividing a
sardines, and green vegetables. person’s weight in kilograms (kg) by

his or her height squared in metres (m).

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