Lecture 1

Question 1

• Explain what carbohydrates are and the main source

Answer 1

are polyhdroxy aldehydes or ketones or subtances that yield such compouns on hydrolysis

the main source comes from plants as starch

Question 2

• Name 3 foods which contain little or no carbohydrates

Answer 2

1. meats
   
   2. egg
   3. non-starchy veggies like leafy greens

Question 3

• Distinguish between the categories of carbohydrates based on
  nutritional versus chemical perspectives.

Answer 3

• Nutritional Perspective:
  - three categories: sugar, starches and dietary fibre
  - Simple Carbohydrates: These are sugars, both natural (found in fruits, honey, and milk) and added sugars (found in processed foods and sweets). They provide a quick source of energy but can lead to rapid blood sugar spikes.
  - Complex Carbohydrates: Found in foods like whole grains, legumes, and starchy vegetables, these carbohydrates take longer to digest, providing a more sustained release of energy.
  -
  
  • Chemical Perspective:
    
    • Monosaccharides: contain a single polyhdyoxy aldehyde or ketone unit (ex: glucose or fructose)
    • Disaccharides: made of two monosacchride units linked together by a covalent bond (ex: sucrose)
    • oligosacchrides: have from 3-19 monosacchride units (raffinose)
    • polysaccharides: has very long chains of hundreds/thousands of monosacchride units, which are either straight or branched (ex: cellulose, gylcogen, starch)

Question 4

• Explain the reasons that nutritional and chemical perspectives
  are different

Answer 4

• Nutritional Perspective:
  - Focus on Health Effects: Nutritional perspectives often categorize carbohydrates based on their impact on health. Nutritional perspectives are concerned with how different carbohydrates affect the body, including aspects like digestion, blood sugar levels, and overall health.
  • Chemical Perspective:
    
    • Structural Characteristics: The chemical perspective classifies carbohydrates based on their molecular structures. Monosaccharides, disaccharides, and polysaccharides have distinct chemical compositions and arrangements of sugar molecules. Chemical perspectives, on the other hand, focus on the structural composition and properties of carbohydrates without necessarily emphasizing their physiological effects.

Question 5

• What are the function of carbohydrates in the body?

Answer 5

1. energy production: through oxidation they provide energy, in our body the bonds are broken and the energy is captured to preform cellular respiration
   
   2. energy storage: if the body has enough energy then excess is stored as glycogen, the long chains of glucose allow for rapid dissemination of glucose when need to make cellular energy
   3. building macromolecules: some glucose that is not absorbed to make energy is converted to ribose/deoxyribose which are important building blocks for macromolecules
   4. role in lipid metabolism: fat sparing effect since as blood glucose levels rise, the use of lipids as energy is inhibited since insulin is released

Question 6

• what foods are not on the health canada plate?

Answer 6

• white bread
  
  • pizza
  • cakes
  • pastry
  • candy
  • milk
  • juice
  • sweetned beverages

Question 7

• what is the amount of fibers people shpild eat and what do they eat?
  -

Answer 7

around 25g/d (women 19-50) but avergely only eat 14-15 g/day

Question 8

• what are the trends in sugar and beverages?

Answer 8

• sugar consumption is decreasing
  
  • juice consumption is much lower and keeps falling

Question 9

• what are the trends in cereal consumption

Answer 9

• oat,barley and rye consumption remain low
  
  • corn flour and meal production peaked in 1997
  • rice consumption is increasing
  • wheat consumption peaked in 2002

Question 10

• what are the vegatble consumption trends

Answer 10

• broccoli, mushrooms, spinach increasing
  
  • tomatoes, carrots fairly stable
  • lettuce, cabbage decreasing

Question 11

• fruit consumption trends

Answer 11

• increases in tropical fruit (bananas, pineapples, mangos)
  
  • increase in melons and strawberries
  • apples and citrus fairly stable
  • decreases in peaches and pears