Introduction to Nutrition - Third Grade

Course Information

• University: University of Baghdad
• College: College of Medicine
• Year: 2024-2025
• Title: Introduction to Nutrition
• Grade: Third Grade
• Module: Introduction to Nutrition
• Speaker: Dr. Ola Hussein Jasim
• Date: 16-9-2024

Objectives

• Know the relevant definitions
• Understand food and diet, including staple foods
• List and classify the main nutrients in food
• Describe energy and nutrient density
• Differentiate between four sets of Dietary Reference Intakes (DRIs)
• Understand dietary guidelines

Definitions of Nutrition

• The science of foods and nutrients, including ingestion, digestion, absorption, transport, metabolism, interaction, storage, and excretion.
• The science that deals with the processes making food components available to an organism for energy needs, growth, maintenance, and optimal health.

Clinical Nutrition

• A medical specialty dealing with the link between disease and nutrition.
• Acute and chronic illnesses can be caused by deficiencies or excesses of dietary components.

Nutrients

• Substances from food used for energy, structure, and regulation of body functions like growth, maintenance, and repair.

Food

• All solid and liquid materials taken by the mouth and utilized by the body to maintain and build tissues.

Diet

• All nutrients entering the body, orally or parenterally (e.g., glucose water, normal saline, parenteral feeding of amino acids and fatty acids).

Staple Foods

• Foods forming the basis of diets, in terms of quantity and frequency of consumption, providing the highest proportion of energy. Examples vary geographically (e.g., cereals, rice, wheat).

Six Classes of Nutrients

• Carbohydrates
• Proteins
• Fats
• Vitamins
• Minerals
• Water

Classifying Nutrients

• Organic: Contain carbon-carbon or carbon-hydrogen bonds (carbohydrates, fat, protein, vitamins).
• Inorganic: Do not contain carbon (minerals, water).
• Essential: Cannot be produced by the body and must be obtained from food (e.g., certain amino acids, vitamins).
• Non-essential: Can be produced by the body (e.g., certain amino acids, cholesterol).
• Macronutrients: Needed in large amounts (carbohydrates, proteins, fats).
• Micronutrients: Needed in smaller amounts (vitamins, minerals).
• Energy-yielding: Provide energy (carbohydrates, proteins, fats).
• Non-energy-yielding: Do not provide energy (vitamins, minerals, water).

Essential Nutrients (Examples)

• Carbohydrates (CHO): Glucose
• Lipids: Linoleic acid, linolenic acid
• Proteins: Amino acids (Lysine, leucine, isoleucine, threonine, phenylalanine, tryptophan, methionine, valine, arginine, histidine)
• Vitamins: Fat-soluble (A, E, K1, and others), Water-soluble(C, B-complex vitamins)
• Minerals: Macrominerals (Ca, Na, K, and others), Microminerals (Fe, Zn, and others).

Non-Essential Nutrients (Examples)

• Biotin: Produced by the GI tract bacteria.
• Cholesterol: Produced by the liver
• Vitamin D: Produced by sunlight
• Vitamin K2: Produced by intestinal bacteria (although Vitamin K1 is not produced by infants)

Dietary Reference Intakes (DRIs)

• A set of four nutrient intake reference standards:
  • Estimated Average Requirements (EAR)
  • Recommended Dietary Allowances (RDA)
  • Adequate Intakes (AI)
  • Tolerable Upper Intake Levels (UL)

Levels of Nutritional Status

• Ideal: Intake sufficient to meet daily needs and keep nutritional stores full.
• Borderline: Intake sufficient for daily needs but reserves may be low
• Malnourished: Insufficient intake; nutrient stores are empty. Can be life threatening and may require medical intervention.
• Overnutrition: Excessive caloric intake leading to obesity and increasing risk of obesity-related diseases (e.g., heart disease, diabetes) and/or vitamin toxicity.

Diet – Planning Principles

• Adequacy
• Balance
• Energy control.
• Nutrient density
• Moderation
• Variety

Food Guide Pyramid (and MyPyramid/MyPlate)

• A visual representation of optimal serving sizes from various food groups.
• USDA-created tool that has evolved and become MyPlate over time.