Module 8: Food Chemistry, Nutrition, and Traditional FoodsFood: Any substances that can be metabolized by an organism to give energy and build tissueTypes: Carbohydrates, Proteins, Fats & OilsOthers: Vitamins, Minerals, Salts
Molecules of Food: Carbohydrates6-C rings, 5-C ringsMono-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
Molecules of Food: Lipids and FatsFats: 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
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)
Sterols• Multiple rings of carbon• Best-known sterols: cholesterol (the building block for all other sterols)• Bile acids, some hormones, Vitamin C
SterolsCholesterol 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
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 IntakeFats and Oils 9 30Carbohydrates 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.
ConceptsSubsistence 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 CharBody 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 Vitaminsdaily need) Good B Vitamins CalciumSource (15- 24% ofdaily need)Fair Source Vitamin C Vitamin A, Calcium (5-14% of Fat, Irondaily need)
Quality Food: Beluga Body Part Meat Blubber Skin Excellent Iron, Protein Fat ProteinSource (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, FatSource (25% Iron, or more of Vitamin daily need) AGood 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, Bdaily need) Vitamins, Calcium
Quality Food: Muskox Body Part Meat Excellent Protein, IronSource (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 acid24% 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 aciddaily need) Good Iron Vitamin C Iron, Fat Source Vitamin C(15-24% ofdaily need) Fair Fat Fat Protein FatSource (5- 14% ofdaily need)
What is special about asubsistence diet in the North?