Exam Notes - BIOL 203

Nutrition

The study of how organisms acquire and utilize food to maintain life.

Nutrition Involves

Digestion (breaking down food), absorption (taking up nutrients), storage (keeping nutrients for later use) metabolism (converting food into energy)

Food

Composed of essential nutrients and non-nutrients (e.g., fiber, phytochemicals) that provide biological activity and health benefits.

Essential Nutrients

Must be obtained from diet; deficiency can lead to diseases (carbohydrates, proteins, fats, vitamins, and minerals).

Non-essential Nutrients

Not critical for survival but beneficial for health (e.g., fiber, phytochemicals).

Carbohydrates

Main energy source. Examples: Glucose, starch, sucrose, fiber.

Proteins

Necessary for growth, repair, and maintenance.

Building blocks: Amino Acids (20 total, 9 essential).

Lipids

Provide long-term energy, vital for cell membranes.

Includes: Triglycerides, phospholipids, cholesterol.

Vitamins

Organic compounds required in small amounts.

Types:

Water-soluble (B-complex, Vitamin C)

Fat-soluble (Vitamins A, D, E, K)

Minerals

Inorganic elements essential for bodily functions.

Categories: Major minerals (e.g., calcium, potassium) and trace elements (e.g., iron, iodine).

Water

 Key for biochemical reactions and temperature regulation.

Factors Influencing Food Choices

• Biological: Hunger, appetite, taste preferences.

• Cultural and Social: Traditions, family influences, social networks.

• Economic and Practical: Cost, availability, convenience.

• Psychological: Emotional comfort, habits, health consciousness.

Dietary Reference Intakes (DRIs)

Quantitative estimates essential for nutrient intake; used for diet planning and assessment.

Goals of DRIs

1. Prevent Deficiency Diseases: Outline necessary amounts to prevent deficiencies.

2. Reduce Risks of Chronic Diseases: Promote health and prevent conditions such as cardiovascular disease.

3. Ensure Safety: Set upper intake levels to prevent toxicity.

Estimated Average Requirement (EAR)

• Meets nutrient needs of 50% of the population.

• Based on diagnostic measures of adequacy.

Recommended Dietary Allowance (RDA)

• Meets needs of 98% of the population.

• The gold standard for nutrient recommendations.

Adequate Intake (AI)

• Used when RDAs are unavailable.

• Based on observed intakes in healthy populations.

Tolerable Upper Intake Level (UL)

• Maximum safe daily intake level.

• Prevents adverse effects, particularly from supplements.

Estimated Energy Requirement (EER)

Calculated based on age, weight, height, and activity level.

Acceptable Macronutrient Distribution Ranges (AMDR)

• Specifies optimal macronutrient intake ranges as a percentage of total calories:

  • Carbohydrates: 45-65%

  • Fats: 20-35%

  • Proteins: 10-35%.

Application of DRIs

• Used by:

  • Health professionals for dietary planning.

  • Policy-makers to establish food guidelines.

• Nutrient recommendations vary by:

  • Gender

  • Life stage (e.g., pregnancy, childhood).

  • Example: Iron recommendations:

    • Women (ages 14-50): 15 mg/day.

    • Men: 8 mg/day.

Major Food Groups in Nutrient Guidelines

1. Grains: Rich in carbohydrates, fiber, vitamins (e.g., folate, thiamin).

2. Milk & Alternatives: Provide calcium, protein, and fortified vitamins.

3. Meat & Alternatives: Good sources of protein, iron, and zinc.

4. Fruits & Vegetables: High in fiber, vitamins (A, C), and potassium.

Atoms

Basic building blocks of matter.

Molecules

Groups of atoms bonded (e.g., water, glucose).

Compounds

Molecules with different elements (e.g., carbon dioxide).

Solutions

Homogeneous mixtures of solutes (minor) in solvents (major).

Aqueous solutions: Water as a solvent (e.g., blood plasma).

Enzymes

Proteins that catalyze biochemical reactions; highly specific.

pH Scale

Measures hydrogen ion concentration; crucial for enzyme activation and digestion.

Digestive System

• Functions: Digestion, absorption, elimination.

• Key organs: Stomach, small intestine, pancreas, liver, gallbladder.

• Villi aid in nutrient absorption.

Circulatory System

• Transports nutrients, oxygen to cells.

• Removes waste via blood and lymph.

Carbohydrates

• Types:

  • Simple: Monosaccharides (e.g., glucose, fructose).

  • Complex: Polysaccharides (e.g., starch, glycogen).

• Digestion and Absorption:

  • Broken down into glucose for energy.

  • Fiber aids digestive health.

• DRIs:

  • 45-65% of total calorie intake.

Lipids

• Types:

  • Triglycerides, phospholipids, cholesterol.

  • Essential fatty acids: Omega-3, Omega-6.

• Functions: Energy storage, insulation, cell membrane integrity.

• DRIs:

  • 20-35% of total calorie intake.

Proteins

• Structure:

  • Composed of amino acids (essential and non-essential).

• Functions:

  • Growth, repair, enzyme, and hormone production.

• Nitrogen Balance:

  • Positive: Growth, recovery.

  • Negative: Starvation, illness.

• DRIs:

  • 10-35% of total calorie intake.

Vitamins

• Classification:

  • Water-soluble: B-complex, Vitamin C.

  • B vitamins crucial for energy metabolism.

  • Deficiency symptoms include weakness, inflamed tongue, and sores.

  • Fat-soluble: Vitamins A, D, E, K.

  • Important for metabolic processes and physiological functions.

Vitamin B1 (Thiamin)

Important for metabolism; rare deficiencies.

Niacin (B3)

Can be synthesized from tryptophan; must be obtained from diet.

Vitamin B6

Coenzyme for over 100 enzymes; high doses can be toxic.

Folate

 Crucial for DNA metabolism; deficiency may lead to spina bifida.

Vitamin B12

Complex absorption process; absence leads to pernicious anemia.

Vitamin C

Essential for collagen synthesis; deficiency known as scurvy.

Vitamin A

Plays roles in vision and immune function.

Vitamin D

Critical for calcium absorption; lack leads to osteoporosis.

Vitamin E

Major fat-soluble antioxidant.

Vitamin K

Key for blood clotting factors.

Minerals

Classification

• Major Minerals: Calcium, potassium, magnesium, sodium.

• Trace Minerals: Iron, zinc, iodine, copper.

Major Minerals

• Calcium: Critical for bones and teeth; helps in nerve communication.

• Phosphorus: Important for bone structure; found in many foods.

• Magnesium: Influences bone formation; found in leafy greens and legumes.

• Sodium: Key for fluid balance, nerve function; excess linked to hypertension.

• Potassium: Associated with lowering blood pressure; found in real foods.

Trace Minerals

• Iron: Essential for oxygen transport; deficiency leads to anemia.

• Iodine: Crucial for thyroid hormone synthesis; deficiency results in goiter.

• Zinc: Important for enzyme function; deficiency affects growth and development.

Water Distribution

Intracellular and extracellular compartments.

Osmosis

Movement of water across membranes to balance solute concentrations.

Role of Water

Transport nutrients and waste; regulate body temperature; facilitate metabolic reactions.

Metabolism

• All chemical reactions in the body.

  • Anabolic: Builds molecules (requires energy).

  • Catabolic: Breaks down molecules (releases energy).

ATP

Energy currency of the cell, produced via glucose and fat metabolism.

Foodborne Illnesses and Pathogens

• Sources: Bacteria, viruses, parasites; Common pathogens include Salmonella, E. coli, Listeria.

• Prevention: Proper cooking, storage, and hygiene practices.

Food Preservation Techniques

Methods: Refrigeration, freezing, pasteurization, irradiation; aim to extend shelf life and reduce contamination.

Risk Management and Regulation

• Agencies: Health Canada, WHO.

• Guidelines: Set limits for pesticide residues and food additives.

Amino Acids

Building blocks of proteins, some are essential for nutrition.

ATP (Adenosine Triphosphate)

Energy storage and transfer molecule in cells.

Carbohydrates

Organic compounds for energy, including sugars and starches.

Cholesterol

A lipid essential for cell membranes and hormone production.

Deficiency Disease

Illness caused by a lack of a specific nutrient.

DRIs (Dietary Reference Intakes)

Nutrient reference values for diet planning.

Enzyme

Proteins that catalyze biochemical reactions.

Essential Nutrients

Nutrients that must be obtained through diet.

Fat-soluble Vitamins

Vitamins (A, D, E, K) stored in body tissues.

Fiber

Carbohydrate aiding digestion, not absorbed by the body.

Lipids

Compounds including fats, oils, essential for energy and structure.

Macronutrients

Nutrients needed in large amounts: carbohydrates, proteins, fats.

Micronutrients

Nutrients required in smaller amounts, such as vitamins and minerals.

Minerals

Inorganic elements key for bodily functions.

Non-essential Nutrients

Beneficial compounds not required in diet.

Phytochemicals

 Bioactive compounds in plants promoting health.

Protein

Essential nutrient for growth, repair, composed of amino acids.

Recommended Dietary Allowance (RDA)

 Nutrient intake level for nearly all healthy individuals.

Solubility

The ability of a substance to dissolve in a solvent.

Vitamins

Organic compounds necessary for metabolic processes.