Human nutrition - CS Biology

• A balanced diet should contain carbohydrate, fat,

  protein, fibre, vitamins, minerals and water.
• Different foods contain different kinds of sugar.

  Eg fruit contains fructose or glucose. Lactose is in

  milk. Table sugar is sucrose.

  Sugar gives us energy, so we call it an energy food.
• Starch is found particularly in bread, potatoes and cereals.

  Starch is a storage molecule, but it does provide us with energy.
• Cellulose is found in plant cell walls

  It is a structural molecule, and supports the plant cell.
• Fats also contain C, H and O, but relatively less

  O. Fats occur in both plant and animal foods.

  Fats – solid at room temperatures.

  Oils - liquid at room temperatures.
• Fats also give us energy. They also provide

  insulation in humans and other mammals, and are

  energy stores.
• Proteins contain C, H and O, and also some

  nitrogen (N) and a little suplhur (S).

  Proteins are found in milk, eggs, meat and fish.
• Proteins are needed for growth and body-building (muscles and skin), and they are also used to make enzymes.
• Minerals contain certain elements essential for

  the proper functioning of our bodies.
• Calcium is needed for hardening our bones and teeth.

  Occurs in foods such as milk, cheese and fish

  Deficiency results in rickets
• Iron is present in haemoglobin, the red pigment in blood used to carry oxygen

  Occurs in a number of foods, especially liver and kidneys

  Deficiency results in anaemia
• Vitamins: a collection of organic substances needed in small quantities in the body. Their overall function is to help control the chemical reactions taking place in the body.
• Vitamin A is Important for our eyes – helps protect their surfaces

  Found in fish liver oil, and carrots.

  Deficiency makes it difficult to see in dim light
• Vitamin C is needed for strong gums

  Found in citrus fruits, green vegetables and blackcurrants

  Deficiency results in scurvy
• Vitamin D is necessary for bones to take up calcium (with the need

  of sunlight)

  Occurs in fish liver oil, and can be made in the skin provided sunlight is

  present.

  Deficiency results in rickets.
• Fibre is necessary for a healthy balanced diet, but the body can’t absorb it. It helps our digestive system to process food and absorb nutrients. It helps your bowel to pass food by making stools soft and bulky. It helps prevent constipation.

  Fibre is found in foods such as brown rice, oats, wholegrain breads and cereals.
• Water makes up more than two-thirds of the weight of the human

  body. It serves as a lubricant, helps regulate body temperature, prevents and relieves constipation. Without enough water we can become dehydrated.
• Nutrients related to different conditions such as In relation to age, In relation to sex, Pregnant females and breastfeeding women.
• Problems cause by unbalanced diets are malnutrition, starvation, constipation, Coronary heart disease (CHD) and obesity.
• A balanced diet for different people is slightly different

  because our energy and nutrient requirements vary

  from person to person.