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					  Module 8: Food Chemistry,
 Nutrition, and Traditional Foods
Food: Any substances that can be metabolized
 by an organism to give energy and build
 tissue

Types: Carbohydrates, Proteins, Fats & Oils

Others: Vitamins, Minerals, Salts
 Molecules of Food: Carbohydrates

6-C rings, 5-C rings
Mono-saccharides (sugar, fructose)
 Dissacharides (lactose, sucrose)
 Polysaccharides (starch, fibre, glycogen)
Carbohydrates are assimilated in the body
 as “mono-saccharides” following digestion
       Glucose: Body’s Primary Fuels
                                           Lactic Acid + ATP + H2O
     Glycogens            Glucose                  (anaerobic)
 (Branched polymers      (monomers)
for short-term storage    (soluble)
       in liver)                    Pyruvic Acid  CO2 + H20 + ATP
                                                 (aerobic)

  •Glucose level in blood stream is highly regulated
  •Aerobic respiration is releasing 90% of the energy stored in
  glucose
Glycogen
Anaerobic
Metabolism



 Aerobic     Pyruvic Acid  CO2 + H20 + 32ATP
Metabolism
 Molecules of Food: Lipids and Fats
Fats: Large biological molecules, diverse
  compositions, insoluble in water (i.e. non-polar in
  nature)
Types:
   –   Fatty acids (assimilable form)
   –   Triglycerides (in blood)
   –   Phospholipids (cell membranes)
   –   Sterols (e.g. cholesterol)
Roles:
   – Source of energy (during sustained activity)
   – Structure of cell membrane
   Free Fatty Acids (one chain)




• Saturated
• Unsaturated (e.g. Omega-3, Omega-6)
                Fatty Acids
• Long-chain fatty acids (12+ carbons) are abundant
  in meats and fish
• Short-chain fatty acids (12 carbons or less) are
  abundant in dairy products
• Cold-water fish are rich in essential omega fatty
  acids
• Unsaturated fatty acids, when cooked, change
  conformation to a “trans” shape (which tend to
  accumulate in blood vessels)
• Unsaturated fats are more prone to react with
  oxygen, causing rancidity (common in stored fish)
Triglycerides
             Phospholipids
• Phospholipids are “modified” triglycerides
  where one fatty acid chain is replaced by a
  phosphate group
• Soluble in water
• Important in cell membrane
Phospholipids
                 Sterols

• Multiple rings of carbon
• Best-known sterols: cholesterol (the
  building block for all other sterols)
• Bile acids, some hormones, Vitamin C
              Sterols




Cholesterol             Sitosterol (the most
                    abundant and common plant
                               sterol)
         Absorption of Lipids
• Fat breakdown occurs in intestines
• Smaller units: fatty acids, glycerol, and
  sterols
• Cholesterol and triglycerides are non-polar,
  hence need “lipoproteins” to carry them in
  the bloodstream
   Molecules of Food: Proteins
• Chains of Amino Acids
• Diverse roles: enzymes, hormones,
  regulators, molecular transports, antibodies,
  building tissue like muscles, and energy
• Made up of C, H, O, N, other ions
               Amino Acids
• Four components
  around a central
  carbon (C)
• One hydrogen
• An amino group (-
  NH2)
• An acid (-COOH)
                             Glycine
• A functional group
           Amino Acids




Essential Amino     Non-essential
 Acid: Leucine      Amino Acid:
                    Asparagine
   Molecules of Food: Vitamins
• Essential organic compounds to ensure
  proper metabolism
• Little caloric value
• Water-soluble vitamins (enter directly into
  bloodstream)
• Fat-soluble vitamins (must be transported
  by carrier proteins)
• Several diseases are associated with vitamin
  deficiencies
Caloric Contents of Food Molecules
 Food Type         Caloric             %
                Content (Cal/g)   Recommended
                                  Caloric Intake
Fats and Oils         9                30

Carbohydrates         4                58

  Proteins            4                10

  Vitamins          Trace         Not Applicable
  Subsistence Food Provisioning
• Nutrition for indigenous people in the Arctic is
  changing rapidly; from 100% to <50% “country
  food”.
• Presence of larger communities, presence of “Co-
  op” or “Bay” stores, and an increasing cash
  economy contribute to changes in feeding habits.
• Lastly, hunting activities are costly when modern
  technologies are used  the “pay off” of
  traditional food provisioning is decreasing.
                   Concepts
Subsistence activities: The hunting, fishing, and
  gathering of local foods for consumption, sharing,
  and trade or barter.

e.g. caribou, whales, seals, marine birds, waterfowls,
   eggs, fruits (largely a carnivore diet)

Note: Commercial trapping or fishing is generally
 not viewed as traditional food gathering; although
 they could be traditional activities.
Example of Subsistence Food
        Economy
  Inupiat households in Barrow, Alaska
       Production vs. Sharing
• Food provisioning is crucial, but sharing is
  an intricate part of subsistence
• Sharing touches upon all members of a
  community, and represents a way of
  establishing and maintaining ties to family
  and within the community at large (e.g.
  support of elders, non-hunting members)
• Sharing is viewed as part of the “culture” of
  indigenous society
       Quality Food: Arctic Char
Body Part       Meat            Skin          Head          Eggs


 Excellent    Protein, Iron Protein, Iron,   Protein, B    Protein,
  Source                    Calcium, Fat     Vitamins     Vitamin C,
 (25% or                                                  Fat, Iron, B
  more of                                                  Vitamins
daily need)
   Good       B Vitamins                      Calcium
Source (15-
  24% of
daily need)

Fair Source    Vitamin C                     Vitamin A,    Calcium
 (5-14% of                                    Fat, Iron
daily need)
            Quality Food: Beluga
 Body Part           Meat           Blubber             Skin

  Excellent       Iron, Protein         Fat            Protein
Source (25% or
 more of daily
    need)
 Good Source                      Protein, Omega-
  (15-24% of                        3 fatty acid
  daily need)

Fair Source (5-       Fat              Iron         Fat, Vitamin A
 14% of daily
     need)
               Quality Food: Caribou
 Body Part      Meat       Blood      Liver       Bone          Stomach      Fat
                                                 Marrow         Contents

  Excellent    Protein      Iron     Protein,                                Fat
Source (25%                           Iron,
 or more of                          Vitamin
 daily need)                            A
Good Source     Iron, B   Protein                Iron, Fat         Iron,     Iron
(15-24% of     Vitamins                                         Vitamin A
daily need)


Fair Source      Fat,         B       Fat,      Protein, Fat,   Protein,    Protein
 (5-14% of     Calcium    Vitamins   Calcium     Vitamin A       Fat, B
daily need)                                                     Vitamins,
                                                                Calcium
     Quality Food: Muskox
 Body Part           Meat

  Excellent       Protein, Iron
Source (25% or
 more of daily
    need)
 Good Source      B Vitamins
  (15-24% of
  daily need)

Fair Source (5-    Vitamin C
 14% of daily
     need)
       Quality Food: Polar Bear
   Body Part            Meat             Blubber

 Excellent Source    Iron, Protein     Vitamin A, Fat
 (25% or more of
    daily need)

 Good Source (15-                    Omega-3 fatty acid
24% of daily need)


Fair Source (5-14%       Fat            Iron, Protein
   of daily need)
                Quality Food: Ring Seal
 Body         Intestine    Liver      Blubber        Meat        Brain      Eyes
 Part
 Excellent     Protein       Iron,        Fat,        Iron,       Iron,    Vitamin A,
  Source                   Protein,   Vitamin A,    Protein, B   Protein    Protein,
 (25% or                  Vitamin A    Omega-3      Vitamins                  Iron
 more of                               fatty acid
daily need)
   Good         Iron      Vitamin C      Iron,                    Fat
  Source                              Vitamin C
(15-24% of
daily need)


   Fair          Fat         Fat       Protein         Fat
Source (5-
  14% of
daily need)
   What is special about a
subsistence diet in the North?

				
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