Module 8 food chemistry, nutrition, and traditional foods

Module 8: Food Chemistry, Nutrition, and Traditional FoodsFood: Any substances that can be metabolized by an organism to give energy and build tissue Types: Carbohydrates, Proteins, Fat

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

(anaerobic)

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 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 are “modified” triglycerides where one fatty acid chain is replaced by a phosphate group

• Soluble in water

• Important in cell membrane

Phospholipids

• Multiple rings of carbon

• Best-known sterols: cholesterol (the building block for all other sterols)

• Bile acids, some hormones, Vitamin C

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

Essential Amino

Acid: Leucine

Non-essential Amino Acid:

Asparagine

Amino Acids

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

Caloric Contents of Food Molecules

Food Type Caloric

Content (Cal/g) Recommended %

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 op” or “Bay” stores, and an increasing cash

“Co-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

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

Body Part Meat Skin Head Eggs

Protein, Iron Protein, Iron,

Fat, Iron, B Vitamins

Quality Food: Arctic Char

Quality Food: Beluga

Quality Food: Caribou

Marrow Contents Stomach Fat

Fair Source

(5-14% of

daily need)

Fat, Calcium VitaminsB CalciumFat, Protein, Fat, Vitamin A Protein, Fat, B

Vitamins, Calcium

Protein

Quality Food: Muskox

Excellent Source (25% or

Quality Food: Polar Bear

Quality Food: Ring Seal

Fat, Vitamin A, Omega-3 fatty acid

Iron, Protein, B Vitamins

Iron, Protein Vitamin A, Protein,

What is special about a subsistence diet in the North?