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?