HSB NUTRITION PT 1

• Nutrition


  The process by which living organisms obtain or make food
• Nutrients humans need


  • Provide energy
  • Enable growth and development
  • Keep healthy
• Diet


  The food an animal eats
• Nutrients required in the human diet

  • Carbohydrates
  • Proteins
  • Lipids (macronutrients)
  • Vitamins
  • Minerals
  • Water
  • Dietary fibre
• Carbohydrates


  • Molecules composed of carbon, hydrogen and oxygen atoms
  • Can be classified into monosaccharides, disaccharides and polysaccharides
• Monosaccharides


  The simplest carbohydrate molecules, have the formula C6H12O6, are all reducing sugars
• Disaccharides


  Formed by chemically joining two monosaccharide molecules, have the formula C12H22O11, are all reducing sugars except sucrose
• Polysaccharides


  Formed by joining many monosaccharide molecules into straight or branched chains, include starch, cellulose and glycogen
• Proteins


  Molecules composed of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur and phosphorus atoms, form small molecules known as amino acids
• Proteins


  • Their chemical structure can be changed by heat or certain other chemicals (denatured)
  • Some are globular and soluble in water, others are fibrous and insoluble
  • They react with biuret reagent
• Lipids


  Fats and oils, molecules composed of carbon, hydrogen and oxygen atoms, each made up of three fatty acid molecules and one glycerol molecule
• Recognizing carbohydrates, proteins and lipids

  1. Reducing sugars test: add Benedict's solution, heat

  2. Non-reducing sugars test: add acid, heat, add Benedict's solution, heat

  3. Starch test: add iodine solution

  4. Protein test: add sodium hydroxide, copper sulfate

  5. Lipid tests: emulsion test, grease spot test
• Functions of carbohydrates


  Provide energy, for storage (glycogen)
• Sources of proteins


  • Fish, lean meat, milk, cheese, eggs, peas, beans, nuts
• Functions of proteins


  • Make new cells for growth and repair tissues
  • Make enzymes that catalyse reactions
  • Make hormones that control processes
  • Make antibodies to fight disease
  • Provide energy
• Sources of lipids


  • Butter, vegetable oils, margarine, nuts, fatty meats
• Functions of lipids


  • Make cell membranes of new cells
  • Provide energy
  • For storage
  • For insulation
• Vitamins required


  • Fat soluble: A, D, E, K
  • Water soluble: B group, C
• Minerals required


  • Calcium, iron, phosphorus, iodine, sodium, potassium, fluorine
• Functions of vitamins and minerals for healthy growth and development
• Vitamins and minerals are only required in small amounts but are essential
• Vitamin A functions


  • Keeps skin, cornea and mucous membranes healthy
  • Helps vision in dim light
  • Strengthens immune system
• Vitamin B1 functions


  • Aids respiration to produce energy
  • Needed for proper nervous system functioning
• Vitamin C functions


  • Keeps tissues healthy
  • Strengthens immune system
  • Helps absorb iron
• Vitamin D functions


  • Promotes calcium absorption
  • Builds and maintains strong bones and teeth
  • Strengthens immune system
• Calcium functions


  • Builds and maintains healthy bones and teeth
  • Helps blood clot
• Iron functions


  • Makes haemoglobin to transport oxygen for respiration
• Deficiency diseases


  Caused by shortage or lack of essential vitamins or minerals in the diet
• Deficiency diseases


  • Night blindness (vitamin A)
  • Rickets (vitamin D and/or calcium)
  • Anaemia (iron)
• Water


  Essential in the diet, makes up about 65% of the human body, acts as a solvent, reactant, and coolant
• Dietary fibre


  Food that cannot be digested, consists mainly of plant cell walls, husks and bran, adds bulk to stimulate peristalsis and prevent constipation
• Constipation


  Condition where faeces are dry, hard, difficult and painful to pass, and passed infrequently
• Diarrhoea


  Condition where faeces are passed frequently and in liquid form, usually a symptom of gastroenteritis
• Causes of constipation


  • Not enough dietary fibre
  • Not enough water/fluids
  • Lack of exercise
  • Change in diet/routine
  • Ignoring urge to defecate
  • Stress, anxiety, depression, medications
• Effects of constipation


  • Bloating
  • Abdominal pain
  • Haemorrhoids
  • Faecal impaction
  • Colorectal cancer
• Causes of diarrhoea


  • Viral infections (e.g. norovirus)
  • Bacterial infections (e.g. Salmonella, E. coli, Shigella)
  • Parasitic infections (e.g. Giardia)
  • Conditions like IBS, colorectal cancer, coeliac, Crohn's
• Effects of diarrhoea


  • Dehydration
  • Electrolyte imbalance
  • Impaired kidney function
  • Malnutrition (severe cases)
• Food poisoning is a common cause of diarrhoea from eating contaminated food
• Diarrhoea is usually a symptom of gastroenteritis
• Causes of Constipation


  • Not eating enough dietary fiber
  • Not drinking enough water or other fluids
  • Not exercising or being inactive
  • A change in diet or daily routine
  • Ignoring the urge to defaecate
  • Stress, anxiety or depression, and certain medications