Health & Nutrition

• Nutrients needed for a healthy diet

  • Carbohydrates
  • Lipids
  • Proteins
  • Vitamins
  • Minerals
  • Water
  • Fibre
• Carbohydrates


  Used for energy in respiration
• Lipids


  A store of energy, protection for organs, insulation from heat loss
• Proteins

  Used for growth and repair
• Vitamins


  Needed to keep you healthy
• Minerals


  Needed to keep you healthy
• Water


  Needed in all cells and body fluids
• Fibre


  To aid in digestion by providing bulk to keep food moving through the digestive system
• Foods high in carbohydrates

  • Bread, pasta, sugary foods (fruits and sugar)
• Foods high in lipids

  • Fats and oil like butter, margarine etc.
• Foods high in proteins


  • Meat, fish, eggs, beans
• Foods high in vitamins


  • Fruit, vegetables, meat
• Foods high in minerals


  • Milk, cheese, green vegetables and fruit
• Foods high in fibre


  • Cereals, fruit, nuts and vegetables
• Balanced diet


  A diet which contains all the different types of food groups, eaten in the right amounts
• Iodine solution


  Chemical used to test for starch
• Ethanol and water


  Chemicals/substances used to test for lipids
• Benedict's solution


  Substance used to test for sugar (pale blue)
• Biuret solution


  Substances used to test for protein (made from copper sulfate solution and sodium hydroxide)
• Iodine solution turns dark blue/black


  In the presence of starch
• Positive test for fats


  Two separated layers in the test tube with the top layer being cloudy white
• Positive test for sugar


  Solution starts blue then turns: Green for a low level, Orange for a medium level, Brick red for a high level
• Positive test for protein


  Begins with the biuret solution being blue then turns purple
• Preparing a food solution for solid food

  1. Crush sample of solid food in pestle and mortar

  2. Add distilled water to crushed food

  3. Mix

  4. Filter solution to remove all solid material, using funnel and filter paper
• Unbalanced diet


  A diet where one or more of the food groups is lacking or eaten in the wrong amounts
• It's unhealthy to be underweight as this can lead to: health problems such as a low immune system, a lack of energy and being too tired, more likely to suffer from lack of vitamins and minerals
• It's unhealthy to be overweight as it can lead to: Heart disease, Stroke, Diabetes, Some cancers
• Cause of overweight

  If a person eats too much fatty foods or takes in more energy than they use then their body stores the excess energy as fat
• Deficiency disease


  When someone is lacking in one or more vitamins or minerals and as a result suffers from health problems because of it
• Factors that can affect the amount of energy someone needs

  • Age (as it can affect growth rate)
  • Body size
  • How active they are (more exercise requires more energy)
• Digestion

  When large molecules of food are broken down into smaller molecules in order to be absorbed into the bloodstream by the body
• Main parts of the digestive system

  • Mouth
  • Gullet/oesophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus

  
• Functions of the main parts of the digestive system

  • Mouth – food is chewed and mixed with saliva
  • Gullet/oesophagus- tube which connects the mouth to the stomach
  • Stomach- churns/mixes chewed food with digestive juices and acid
  • Small intestine- where the majority of nutrients are absorbed into the bloodstream
  • Large intestine- where the excess water is absorbed back in to our bodies
  • Rectum- solid waste (faeces) is stored here before being expelled from the body
  • Anus- Muscular ring which the faeces passes through to get out the body

  
• Substances produced by the stomach to help digestion

  • Enzymes called protease to help digest protein
  • Hydrochloric acid (HCl) which kills microorganisms that might make us ill (and produces the correct pH for the protease enzymes to function)
• Small intestine adaptations to absorb nutrients

  • Thin walls to allow it to absorb nutrients quickly
  • Covered in tiny structures called villi which increase the surface area of the intestines
  • Good supply of blood to carry away absorbed food molecules
• Catalyst


  A substance that can speed up chemical reactions without being used up itself
• Enzymes


  Special proteins that can break large molecules into smaller ones, also known as biological catalysts
• Carbohydrase enzymes


  Break down carbohydrates
• Carbohydrates broken down into


  Sugars like glucose

  
• Protease enzymes


  Break down proteins