Essential Idea:
A balanced diet is
essential to human health
Understandings:
- Essential nutrients cannot be synthesised by the body, therefore they have to be included in the diet
- Dietary minerals are essential chemical elements
- Vitamins are chemically diverse carbon compounds that cannot be synthesised by the body
- Some fatty acids and some amino acids are essential
- Lack of essential amino acids affects the production of proteins
- Malnutrition may be caused by a deficiency, imbalance or excess of nutrients in the diet
- Appetite is controlled by a centre in the hypothalamus
- Overweight individuals are more likely to suffer hypertension and type II diabetes
- Starvation can lead to breakdown of body tissue
Applications:
- Production of ascorbic acid by some mammals, but not others that need a dietary supply
- Cause and treatment of phenylketonuria (PKU)
- Lack of Vitamin D or calcium can affect bone mineralization and cause rickets or osteomalacia
- Breakdown of heart muscle due to anorexia
- Cholesterol in blood as an indicator of the risk of coronary heart disease
Skills:
- Determination of the energy content of food by combustion
- Use of databases of nutritional content of foods and software to calculate intakes of essential nutrients from a daily diet