week 8 - macronutrients

Question 1

what are the structural components of carbohydrates? `

Answer 1

1. Monosaccharide - 1 saccharide
   * Includes glucose, fructose, galactose
2. Disaccharide - 2 of the mono.S linked together
   * Includes maltose = glucose + glucose
   * Sucrose = glucose + fructose
   * Lactose = glucose + galactose
3. Ogliosaccarides = meaning “few”
4. Polysaccharides = meaning “many” monosaccharides linked together in long chains
   * Includes starch and fibres (cellulose)

Question 2

what is sucrose and lactose made up of?

Answer 2

• both are disaccharides
  1. sucrose = glucose + fructose
  2. lactose = glucose + galactose

Question 3

what is ogliosacchardies and polysacchardies?

Answer 3

oglio - means a “few”

poly - means many monosacchardies linked together in long chains

Question 4

what are the main functions of carbohydrates?

Answer 4

1. Main source of energy -> allows body to undertake biological work
   * CHO breaks down into glucose and transported in the bloodstream
   
   • The glucose is then synthesised to glycogen -> stored or used directly as energy
2. Glycogenesis
   * Formation of glycogen from glucose
   * This occurs if CHO ingested exceed the energy needs
   * Occurs In the liver
3. Glycogenolysis
   * Reformation of glucose FROM glycogen
   * This occurs when body is in a fasted state
   * Stores are relatively small and they dont last very long
4. gluconeogensis
   * Formation of glucose from AMINO ACIDS
5. Protein sparer
   * When individuals go on extremely low energy diet
   * LOWERS GLYCOGEN levels
   * This in turn put demands on body protein -> gluconeogensis via the action of cortisol
   * Result: loss of lean muscle tissue
6. Fuel for the CNS
   * The brain uses blood glucose almost exclusively at its fuel
   * Blood glucose is therefore regulated to narrow limits

Question 5

what happens when carbohydrates are consumed at too high amounts or too low?

Answer 5

• Hypoglycaemia: symptoms of dizziness, anxiety, tachycardia, impaired exercise performance
• Hyperglycaemia: often occurs in diabetes

Question 6

how many grams of CHO are recommended to avoid ketosis?

Answer 6

50-100g CHO a day

Question 7

What is the definition of fibre?

Answer 7

• No universally accepted definition
  
  • Plant material - mostly CHO
  • Resists digestion
  • Able to act as a substrate (food) for micro-organisms
    *

Question 8

what are the different types of fibre?

Answer 8

Many different types of fibre

* Non-starch polysaccharides 
* Resistant starch 
* Non digestible ogliosaccharides - has a role in functional foods (prebiotics) 
* Other

Question 9

what are the two broad categories of fibre?

Answer 9

1. soluble
   - slows down CHO digeston and increases fullness
2. insoluble fibre
   - absorbs water -> adding to faecal bulk
   - promites bowel movements

Question 10

Why is fibre needed to maintain bowel health?

Answer 10

• Increases stool bulk
• Binds toxins/carcnogens
• Production of short chain fatty aicds i.e. butyric acid
• Helps prevent: colon cancer, diverticular disease, constipation

Question 11

How does fibre help with chronic diseases?

Answer 11

• Affects carbohydrate absorption and transit time
• Affects satiety
• Displaces fats in the diet
• Binds Bile -> increasing extortion -> forces liver to use cholesterol to make new bile acids
• MAY assist in preventing: overweight, diabetes, cardiovascular disease

Question 12

What are lipids?

Answer 12

• Lipids are groups of compounds that dissolve in organic solvents such as petrol chloroform, but are insoluble in water
• Oils: liquid at room temperature
• Fats: solids at room temperature

Question 13

what are the structural compoennts of saturated fatty acids?

Answer 13

• when C is attached to the most possible no. of H atoms

Question 14

what are unsaturated fatty acids?

Answer 14

• monounsaturated fatty acid: contains 1 DB

* Polyunsaturated fatty acids: contains 2 or MORE DB

Question 15

What is the difference between the structure of trans fatty acids and naturally occurring fatty acids?

Answer 15

• Most naturally occurring fatty acids are cis conformation

* Trans fatty acids have at least one double bond in the trans conformation

Question 16

What are the main functions of lipids in the body?

Answer 16

1. Energy source and reverse
   * One of the main storage forms of energy in the body
   
   • Well nourished person -> 80-90% approx. of ER are composed of lipids
     * Human body males (12-20%) and females (18-30%) fats
   • Provides long term reverses for metabolic fuels
   • Triglyceride is most important storage form
   • Adipose tissue is the biggest resivour of storage fats
2. Provides essential nutrients
   * 20g of fat needed per day to meet suffiecnt needs of vitamin A, K , D, E
3. Protection and insulation
   * Protects against trauma to organs
   * Fat below skin provides insulation
   * Excess body fat hinders in heat
4. Palatibility and satiety
   * Can add texture and flavour to foods
   * Can assist in transporting flavours

Question 17

What are lipoproteins?

Answer 17

• Major lipid transporters in the blood
  1. LDL (low density lipoprotein) = delivers cholesterol to arterial tissue “bad” cholesterol
• When you eat saturated/trans fat -> LDL generated -> clumps of cholesterol developed and binds with calcium -> soapy textured material (calcification) which is really hard to break down -> therefore blocks arteries
  1. HDL (high density lipoprotein) = removes cholesterol from arterial walls and delivers it to the liver for excretion in bile - aka “good cholesterol”
• HDL removes cholesterol from arterial walls
• HDL delivers these to the liver for excretinon in bile “good cholesterol”

Question 18

What are the health effects of consuming trans fatty acids?

Answer 18

• Increases amount of low-density lipoprotein cholesterol (LDL)
• Decreases amount of beneficial high-density lipoprotein cholesterol (HDL)
• Therefore increases the risk of atherosclerosis even in comparison to saturated fats which increases HDL

Question 19

what is the structure of proteins?

Answer 19

• Amino acids
  
  • Each protein has its own specific sequence of amino acids
  • The 20 amino acids are like an alphabet
  • All amino acids have the same basic structure
    
    • A C with 3 groups attached to it
    • An amine group (-NH2)
    • An acid group (-COOH)
    • Hydrogen atom(H)

Question 20

what is a peptide, dipeptide, tripeptide, polypeptide?

Answer 20

A protein consisting of one AA = peptide (adrenaline) 
Two AA’s = dipeptide 
Three AA’s = tripeptide
4 + AA’s = polypeptide 
Most proteins have more than 50

Question 21

What is the importance of proteins in the body?

Answer 21

• Protein forms muscle, bone, skin and other tissues
• Enzymes, blood transport molecules, intracellular matrix, hair, finger nails
• Hormones

Question 22

what are the main functions of proteins in the body?

Answer 22

1. Growth and maintainiance
   * Anabolism = growth maintenance
   * Cells are constantly growing and degrading (breaking down) their proteins, therefore important to be constantly replaced
   * Protein forms integral parts of most body structure: skin, hair, fingernails, muscles, organs
2. Transportation
   * Haemoglobin (protein) found in red blood cells -> carries oxygen from lungs to body’s cells
   * Lipoproteins: transport lipids around the body
3. Fluid-electrolyte and acid-base balance
   * We have proteins in our cell wall structure that can active or passively transport fluid between inside and outside environment of cell
   * Increase in protein intake -> increase protein production -> increases osmotic pressure
   * Acid base balance: blood proteins (albumin) can accept or release H ions to keep blood PH under control
4. Enzymes, hormones and anti-bodies
   * Enzymes are made up of globular proteins
   
   • They are protein catalysts -> essential for all life processes; digestive and cellular
     * Antibodies: screasted in response to foreign particles
   • They form the immune system response
     * Hormones:
   • chemical messengers - regulate body processes
   • Thyroid and insulin
5. Energy source
   * Protein is only used in the body’s energy production (5-10%) when required
   * Amino aids will be scarified for energy and glucose if necessary (while maintaining glucose priority of brain function)
   * When glucose and fatty acids are limited - gluconeogenesis forms glucose FROM amino acids
   * Overtime: low energy results in wasting of lean body tissue (i.e. muscle)

Question 23

What are the health effects of inadequate protein?

Answer 23

• Protein-energu malnutrition (PEM) = lack of insufficient dietary protein and or energy
  
  • Examples of this: marasmus or kwashiorkor
  • Marasmus: is a form of malnutrition. Can occur in anyone who has severe malnutrition
    
    • Tends to occur in children
    • Children with this condition have lost alot of muscle mass and subcutaneous fat
  • Kwashiorkor: form of severe protein malnutrition
    
    • Characterised by edema - accumulation of fluids around the body
    • People with kwashiorkor have sufficient carloeis intake but INSUFFICIENT amounts or protein (therefore different from marasmus)

Question 24

In Australia where does majority of malnurishment come from?

Answer 24

Majority of malnurishment in Australia is disease related

Question 25

What are the health effects of excess protein?

Answer 25

* Increase in urea excretion * Obligatory H2O loss may -> dehydration * Risk groups are athletes, elderly age group and infants * Elderly usually not from excess protein intake but when their kidneys are not func. Properly t.f. cannot digest protein properly * Infants excess protein intake usually from when formula fed and when formula made not by instructions * Osteoporosis * Ca excretion increases with high protein intakes * Heart disease - homocysteine * Cancer - limited evidence * Kidney disease (listen to the lecture) * Difficult to determine the effects of protein intake from a diet that is high in meat

Question 26

What is the difference between essential and non-essential amino acids?

Answer 26

* Essential amino acids: amino acids that you get from foods because your body cannot make them * 9/20 amino acids are essential BUT adults ONLY NEED 8 of them * 9th essential amino acid = histidine -> only essential for infants * Non-essential amino acids: amino acids which are synthesised by your body - so it is not essential to be part of the diet * But they do HAVE ESSENTIAL ROLES IN THE BODY

Question 27

What is complete protein and protein quality?

Answer 27

* Complete protein: food sources that contain all of the 9 essential amino acids (remember adults only need 8 of the 9 essential amino acids) in the quantities and correct ratio to facilitate healthy development and growth * Protein quality: level of protein completeness * Most protein from animal sources - meat, poultry, fish, eggs are complete proteins * Gelatin is a type of animal protein that is NOT complete * Incomplete protein: protein food sources that do NOT contain all 9 essential amino acids * Usually from plant sources

Question 28

Because most plant based protein foods are incomplete proteins, what can vegetarians/vegans do to compensate for this?

Answer 28

Protein complementation: combing 2 incomplete protein foods that supply the amino acids missing in the other, combined to yield a complete protein profile.

Question 29

What is limiting amino acids (AA’s)? Give an example of a food source that contains a limiting AA’s.

Answer 29

* Limiting amino acids: is a essential amino acid that is not found in food (listen to lecture for more explanation) -> it is in insufficient amounts in a type of food * Most/all plant based protein sources are incomplete protein as they have limiting amino acids (are deficient in some essential amino acids) * Example: cereals * Although they contain SOME amounts of lysine -> NOT suffiencent enough to FORM A PROTEIN * Therefore lysine is the limiting protein in cereals * To obtain adequate amounts of lysine: combine cereals with lysine-rich foods (vegetables, eggs, dairy, fish, meat)

Question 30

What are complementary AA’s?

Answer 30

* Complementary AA: 2 or more protein sources that complement each other to create a complete protein profile * Examples * Grains + legumes e.g. rice + beans * Grains + dairy e.g. cheese sandwich, pasta/cheese * Legumes + seeds e.g. hummus, falafel

Question 31

How can individuals that follow a vegetarian/vegan diet ensure they are getting adequate amounts of protein?

Answer 31

* Diversity is key * When there is variation: plant sources can successfully meet protein needs * Consuming a diverse range of plant sources allows for protein complementation