Module 8 Food Chemistry Nutrition and Traditional Foods

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 v 6 -C rings, 5 -C rings v. Mono-saccharides (sugar, fructose) Dissacharides (lactose, sucrose) Polysaccharides (starch, fibre, glycogen) v. Carbohydrates are assimilated in the body as “mono-saccharides” following digestion

Glucose: Body’s Primary Fuels Lactic Acid + ATP + H 2 O Glycogens (Branched polymers for short-term storage in liver) Glucose (anaerobic) (monomers) (soluble) Pyruvic Acid CO 2 + H 20 + 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 Metabolism Pyruvic Acid CO 2 + H 20 + 32 ATP

Molecules of Food: Lipids and 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 (NH 2) • An acid (-COOH) • A functional group Glycine

Amino Acids Essential Amino Acid: Leucine Non-essential 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) Fats and Oils 9 % Recommended Caloric Intake 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 “Coop” 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 Excellent Source (25% or more of daily need) Meat Skin Protein, Iron, Calcium, Fat Head Eggs Protein, B Vitamins Protein, Vitamin C, Fat, Iron, B Vitamins Good Source (1524% of daily need) B Vitamins Calcium Fair Source (5 -14% of daily need) Vitamin C Vitamin A, Fat, Iron Calcium

Quality Food: Beluga Body Part Meat Blubber Skin Excellent Source (25% or more of daily need) Iron, Protein Fat Protein Good Source (15 -24% of daily need) Fair Source (514% of daily need) Protein, Omega 3 fatty acid Fat Iron Fat, Vitamin A

Quality Food: Caribou Body Part Meat Blood Liver Excellent Source (25% or more of daily need) Protein Iron Protein, Iron, Vitamin A Good Source (15 -24% of daily need) Iron, B Vitamins Protein Fair Source (5 -14% of daily need) Fat, Calcium B Fat, Vitamins Calcium Bone Marrow Stomach Contents Fat Iron, Vitamin A Iron Protein, Fat, Vitamin A Protein, Fat, B Vitamins, Calcium Protein

Quality Food: Muskox Body Part Meat Excellent Source (25% or more of daily need) Protein, Iron Good Source (15 -24% of daily need) B Vitamins Fair Source (514% of daily need) Vitamin C

Quality Food: Polar Bear Body Part Meat Blubber Excellent Source (25% or more of daily need) Iron, Protein Vitamin A, Fat Good Source (1524% of daily need) Fair Source (5 -14% of Omega-3 fatty acid Fat Iron, Protein

Quality Food: Ring Seal Body Part Intestine Liver Blubber Excellent Source (25% or more of daily need) Protein Good Source (15 -24% of daily need) Iron Vitamin C Iron, Vitamin C Fair Source (514% of daily need) Fat Protein Iron, Fat, Protein, Vitamin A Omega-3 fatty acid Meat Brain Eyes Iron, Protein, B Vitamins Iron, Protein Vitamin A, Protein, Iron Fat

What is special about a subsistence diet in the North?