Chapter 4 Dietary Requirements

• Food allergies and food intolerances are physiological conditions that dictate which foods should be excluded from someone's diet in order to stay healthy
• Physiology of food allergies and intolerances


  • How allergy and intolerance differ, their respective symptoms, causes and management, with a focus on allergies identified by Food Standards Australia New Zealand and lactose, gluten and FODMAP intolerances
• Osteoporosis

  The condition where bone deteriorates, becoming fragile and brittle, leading to a high risk of fracture and breakages
• The symptoms of osteoporosis and osteoarthritis present later in life but it is the consumption of the recommended dietary intake of calcium throughout life that can help in the prevention
• Sex


  The male and female bodies have a different structure and grow and develop differently
• Nutrient intakes


  Vary according to energy needs and the growth, maintenance and repair of the body cells at different stages of the lifespan
• Lactose


  The sugar found in milk and milk products
• Serving size


  The recommended amount of a food group to consume
• The Australian Dietary Guidelines recommend serving sizes for each food group
• A food allergy is the body's immune system reacting to a foreign substance, and an allergic reaction to food can be triggered by even very small amounts and the reaction can be mild to severe
• Common food allergens


  • Eggs
  • Milk
  • Shellfish
  • Sesame
  • Soy
  • Peanuts
  • Tree nuts (e.g. almonds, cashews)
• Food allergy


  An abnormal immunological reaction to food caused by a foreign substance, usually protein. Some severe food allergies can cause an anaphylactic reaction and as a result are life-threatening (for example, peanut allergy)
• Immune system


  The body's defence against infection. It is made up of cells and proteins that create a complex network that recognises a germ in the body and creates microbes to destroy the germ
• Allergic reaction


  When the body overreacts to an allergen and triggers a series of symptoms that vary for each individual and depend on the severity of the reaction. A reaction can be mild (sneezing) or life-threatening (anaphylaxis). An allergic reaction relates to the immune system
• Anaphylaxis


  Extreme sensitivity to a food product; can be life-threatening
• Consuming the allergen causes the body's immune system to produce antibodies to fight against the substance. Reactions are quick and can be severe, requiring urgent medical attention. An example of the body's immune response is impaired airways or swelling of the tongue.
• Allergen


  A substance that can cause an allergic reaction. There are many different allergens. When in the body, an allergen binds with a protein and triggers the allergic reaction
• Antibodies


  A protein produced by the body's immune system when the body detects a harmful substance. The harmful substance is referred to as an antigen. The body creates a unique antibody to defend against a specific type of antigen
• Symptoms of a mild allergic reaction


  • Swelling of the mouth, face, lips and eyes
  • Tingling sensation of the mouth
  • Redness or hives
  • Abdominal pain or vomiting
• Symptoms of a severe allergic reaction - anaphylaxis


  • Swelling of the tongue
  • Swelling/tightness of the throat
  • Difficulty breathing
  • Noisy breathing, wheezing or persistent cough
  • Pale complexion
  • Loss of consciousness
• Food intolerance


  A chemical reaction that occurs in the body when a particular food or drink is consumed. Different from a food allergy, a food intolerance is not an immune response and will not lead to anaphylaxis. A person who suffers an intolerance will find they can tolerate a certain amount of the trigger food, but when they have had too much, they become unwell with symptoms that vary for each person.
• Symptoms of food intolerance

  • Headaches
  • Bloating
  • Diarrhoea
  • Rash
  • Stomach cramps
• Coeliac disease


  A disease of the small intestine that results in a permanent intolerance to gluten, the protein found in wheat, oats, barley and rye cereals. Consuming gluten damages the villi or surface area of the small intestine, preventing the absorption of nutrients.
• Gluten


  A protein substance found in many cereal products, including wheat, rye, barley and oats, which gives dough its elastic texture
• Symptoms of coeliac disease


  • Cramping and bloating
  • Nausea
  • Flatulence
  • Diarrhoea
  • Constipation
  • Fatigue
  • Irritability
  • Anaemia
  • Weight loss
• The long-term effects of consuming gluten if a person is gluten-intolerant include osteoporosis, due to calcium being unable to be absorbed, and bowel damage and malnutrition, due to the prevention of nutrient absorption.
• Lactose intolerance


  A condition where the body is unable to digest lactose, the sugar found in milk and milk products. The body does not have sufficient amounts of the enzyme lactase to break the lactose down into simpler sugars.
• Symptoms of lactose intolerance


  • Abdominal swelling or bloating
  • Nausea
  • Flatulence
  • Diarrhoea
  • Abdominal pain
• Yoghurt is generally digested well by the body due to its natural bacteria cultures
• FODMAP intolerance


  Fermentable oligosaccharides, disaccharides, monosaccharides and polyols intolerance
• Symptoms of FODMAP intolerance

  • Excessive gas production
  • Bloating
  • Unpredictable bowel habits
  • Lower abdominal pain
• Microbiology of the gastrointestinal tract and accessory organs

  Tongue, salivary glands, pancreas, liver and gall bladder
• Macronutrient digestion, absorption and utilisation


  Sequential process including enzymatic hydrolysis
• Mechanical digestion


  Physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion
• Chemical digestion


  Breaking down of food, through the action of enzymes, into small molecules that can be absorbed and utilised by the body
• Absorption


  How the nutrients are absorbed by the digestive system. Where this occurs is different depending on the macronutrient
• Utilisation


  How the body uses nutrients
• Enzymatic hydrolysis


  The process in which enzymes break the bonds in molecules with the addition of water. This is an important role in the digestion of food
• Microbiota


  The wide variety of micro-organisms (microbiome), including fungi, yeast and bacteria, that live in the gut
• Microbiome


  Collective term that describes the many micro-organisms that live in the human body in different environments, including the gut