Module 8: Food Chemistry, Nutrition, and Traditional Foods

1. 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

2. 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

4. Glucose: Body’s Primary Fuels Lactic Acid + ATP + H2O (anaerobic) Glycogens (Branched polymers for short-term storage in liver) Glucose (monomers) (soluble) 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

5. Glycogen

6. Anaerobic Metabolism Aerobic Metabolism Pyruvic Acid CO2 + H20 + 32ATP

7. 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

8. Free Fatty Acids (one chain) • Saturated • Unsaturated (e.g. Omega-3, Omega-6)

9. 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)

10. Triglycerides

11. Phospholipids • Phospholipids are “modified” triglycerides where one fatty acid chain is replaced by a phosphate group • Soluble in water • Important in cell membrane

12. Phospholipids

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

14. Sterols Cholesterol Sitosterol (the most abundant and common plant sterol)

15. 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

16. 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

17. Amino Acids • Four components around a central carbon (C) • One hydrogen • An amino group (-NH2) • An acid (-COOH) • A functional group Glycine

18. Amino Acids Essential Amino Acid: Leucine Non-essential Amino Acid: Asparagine

19. 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

21. Caloric Contents of Food Molecules

22. 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.

23. 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.

24. Example of Subsistence Food Economy Inupiat households in Barrow, Alaska

29. 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

30. Quality Food: Arctic Char

31. Quality Food: Beluga

32. Quality Food: Caribou

33. Quality Food: Muskox

34. Quality Food: Polar Bear

35. Quality Food: Ring Seal

36. What is special about a subsistence diet in the North?