Food and Nutrients Notes

Learning Outcomes

• Define and Contextualize Food and Nutrients
  • Biological and cultural definitions of food and nutrients
  • Food as sustenance and a cultural/social identity symbol
• Understand the Scientific Basis of Nutrition
  • Major macronutrients and micronutrients and their biological roles
  • How the human body processes food to extract energy and nutrients
  • Application of the Atwater General Factor System for food energy content
• Reflect on Broader Implications of Food Choices
  • Environmental, ethical, and societal factors influencing food production and consumption
  • Individual food choices and their contribution to global challenges (sustainability, food equity)

Definition of a Nutrient

• Nutrient
  • Adjective: "Conveying or supplying nourishment"
  • Noun: "A nutritious substance"
  • Source: Oxford English Dictionary

What is Food?

• Food
  • Origins: Germanic
  • Definition: "Any nutritious substance that people or animals eat or drink to maintain life and growth."
  • Alternative definition: Matter that contains energy which can be extracted to sustain life.
  • Note: Water is matter but does not provide energy, hence not technically classified as food.

Major Nutrients

• What Nutrients Are In Our Foods?
  • Macronutrients:
  • Carbohydrates: Main source of energy
  • Protein: Key for tissue formation and repair, hormone/enzyme production
  • Fat: Stored energy, structural components, signaling molecules
  • Water: Essential for transportation of nutrients and waste
  • Micronutrients:
  • Vitamins: Regulate body processes
  • Minerals: Essential for cellular functions and body tissue

Functions of Nutrients

• Protein: Builds strong muscles, supports the immune system
• Carbohydrates: Quick energy source, structural functions in cells
• Fat: Stored energy, insulation, structural roles
• Vitamins and Minerals: Essential for various body functions
• Water: Maintains hydration, aids digestion, transports nutrients

Energy Content of Food - The Atwater General Factor System

• Developed by Wilbur Olin Atwater, USDA
• Based on heats of combustion for nutrients:
  • Proteins: 17 kJ/g (4.0 kcal/g)
  • Fats: 37 kJ/g (9.0 kcal/g)
  • Carbohydrates: 17 kJ/g (4.0 kcal/g)
• Offers a simple way to understand energy values of foods

Influences on Food Choices

• Factors affecting food choices include:
  • Individual tastes
  • Family
  • Culture
  • Health considerations
  • Age, financial circumstances, and social environment

Digestive Processes

• Accessory Organs (Aid Digestion):
  • Salivary Glands: Produce enzymes for starch and fat digestion
  • Liver: Produces bile for fat digestion
  • Pancreas: Produces digestive enzymes
• Digestive Tract Major Organs:
  • Mouth: Chews food, begins digestion
  • Stomach: Mixes food, begins protein digestion
  • Small Intestine: Main site for nutrient absorption
  • Large Intestine: Absorbs water, forms waste for elimination

Achieving a Healthy Diet

• Five key factors for a healthful diet:
  1. Adequacy: Sufficient amounts of nutrients
  2. Balance: Appropriate amounts of different nutrients
  3. Calorie Control: Energy intake must meet energy expenditure
  4. Moderation: Avoid extreme eating practices
  5. Variety: Consume a range of foods from all food groups

Summary of Healthy Eating Recommendations

• Eat a variety of healthy foods daily, including:
  • Plenty of vegetables, fruits, whole grains, and protein foods (preferably plant-based).
  • Choose healthy fats, limit processed foods
  • Be mindful of food marketing influences on choices.
  • Use food labels to inform decisions on food products.