N1015 Nutrition - Class 8

Nutrition: Science and Impact

Definition and Importance

Nutrition is the science of optimal cellular metabolism and its impact on health and disease. It encompasses the processes by which food and nutrients affect growth and development, cellular function and repair, health promotion, and disease prevention.

• Nutrition affects multiple aspects of health, including hormonal regulation, glucose regulation, immunity, tissue integrity, thermoregulation, development, and cultural practices.

• Understanding nutrition is essential for self-management of health, especially in chronic disease contexts.

Categories of Nutrients

General Overview

Nutrients are substances in food that provide energy, form body structures, and regulate biochemical reactions. There are six general categories:

• Carbohydrates

• Proteins

• Fats

• Vitamins

• Minerals

• Water

Carbohydrates

Structure and Function

Carbohydrates are compounds of carbon, hydrogen, and oxygen. Through photosynthesis, plants convert CO2 and H2O into glucose, the most basic unit of carbohydrates. Most carbohydrates are plant-derived, except lactose (milk sugar).

• Body's preferred source of energy

• Storage form: Glycogen

• Energy value: 1 gram = 4 kcal

• Recommended intake: 55% of daily calories (6-10 g/kg body weight per day)

Types of Carbohydrates

• Simple Carbohydrates: Monosaccharides (glucose, fructose, galactose) and disaccharides (lactose, maltose, sucrose)

• Complex Carbohydrates: Starches (pasta, rice, breads, potatoes) are chains of glucose molecules

• Fibre: Includes both soluble and insoluble types, important for digestive health

Fibre

• Insoluble Fibre: Wheat, rice, bran, whole grain cereals and breads

• Soluble Fibre: Oats, oat bran, peas, beans, root vegetables, citrus fruits

• Both Types: Apples, pears, barley, bananas, prunes, cabbages

Glycemic Index

The glycemic index (GI) measures how quickly carbohydrates in food raise blood glucose levels. Foods with a low GI turn slowly into glucose, while high GI foods turn quickly into glucose. This is especially relevant for diabetes management.

• Low GI: Less than 55

• High GI: Greater than 70

Protein

Structure and Function

Proteins are essential for structure and function in the body. They are made up of amino acids, including 9 essential and 11 nonessential amino acids. High-quality proteins contain all essential amino acids.

• Energy value: 1 gram = 4 kcal

• Recommended intake: 10-35% of daily calories (0.8 g/kg body weight per day)

• High-quality sources: Meat, fish, poultry, cheese, milk, eggs, soybean products, quinoa

Vegetarian Protein

Vegetarians can obtain protein through mutual supplementation, combining foods with different amino acid profiles (e.g., grains and legumes).

• Examples: Soup, chili, hummus with veggies, granola

Protein and Muscle Growth

Exercise, not excess protein intake, stimulates muscle growth. Adequate protein is necessary for tissue repair, but excess protein leads to increased metabolic waste and potential weight gain.

Fat

Types and Functions

Fats are a storage form for energy and are part of cell structures. They are also necessary for the absorption of fat-soluble vitamins (A, D, E, K).

• Energy value: 1 gram = 9 kcal

• Recommended intake: Less than 30% of daily calories

Unsaturated Fats (The Good)

• Mainly from vegetable sources

• Liquid at room temperature

• Examples: Olive oil, safflower oil, soybean oil, nuts, seeds, omega-3 (canola oil, walnuts, fish), omega-6 (leafy veggies, seeds, nuts, grains)

Saturated Fats (The Bad)

• Mainly from animal sources

• Solid at room temperature

• Examples: Butter, cream, lard, fatty meats, cheeses, tropical oils

• Recommended: Less than 10% of daily calories

Trans Fats (The Ugly)

Trans fats are created by hydrogenation, making unsaturated fats act like saturated fats. They are found in processed foods and increase cardiovascular risk.

• Examples: Margarines, shortenings, peanut butter, cookies, donuts, crackers, cakes, fried foods

Cholesterol

Role and Health Impact

Cholesterol is essential for cell membranes, hormone synthesis, and vitamin D production. Genetics influence cholesterol metabolism. High blood cholesterol increases cardiovascular disease risk.

Vitamins

Types and Functions

Vitamins are organic compounds that assist other nutrients in digestion, absorption, metabolism, and excretion. They provide no energy but are vital for health.

• Water-soluble: B vitamins, vitamin C

• Fat-soluble: Vitamins A, D, E, K

Minerals

Types and Functions

Minerals are inorganic compounds serving structural purposes in bones and teeth and are found in body fluids, influencing muscle and nervous system function.

• Major (macro) minerals: Needed in larger amounts

• Trace (micro) minerals: Needed in smaller amounts

Water

Importance

Water is a major component of all body tissues and is essential for survival. It transports nutrients and waste products and is a constituent of blood.

Food Labelling

Required Information

Federal law requires most packaged foods to be labelled with a nutrition facts table, including serving size, calories, nutrients, percent daily values (% DV), and an ingredient list.

• Helps consumers make informed choices about their diet

Nutrition Issues: Past and Present

Historical Deficiencies

In the past, nutritional deficiencies led to diseases such as rickets, scurvy, beriberi, and night blindness.

• Rickets: Vitamin D deficiency

• Scurvy: Vitamin C deficiency

• Beriberi: Thiamine (B1) deficiency

• Night Blindness: Vitamin A deficiency

Current Nutrition-Related Diseases

Today, nutrition issues are linked to chronic diseases such as diabetes, hypertension, metabolic syndrome, hypercholesterolemia, and cancer.

Nutrition Strategies: Local and National Perspectives

Canada's Food Guide

Canada's Food Guide provides recommendations for healthy eating, emphasizing variety and balance across food groups.

Local Initiatives

• Mother Baby Nutrition Supplement: Financial support for low-income expectant women and families with infants

• Poverty Reduction Initiatives: Programs to improve access to healthy food

• School Lunch Programs: Promote healthy eating among children

Food Environment and Food Deserts

Challenges

Food deserts are areas with limited access to affordable and nutritious food. Residents may need to travel long distances or rely on public transportation.

• Contributes to food insecurity and poor nutrition

Solutions

• Community gardens

• Local markets

• Support for neighborhood convenience stores

• Mobile markets

Current Food Context

Issues

• Food insecurity

• Lack of cooking and food preparation skills

• Portion distortion

• Targeted marketing to children

• Sugar-sweetened beverages

Provincial Priorities and Vision

Healthy Eating Plan

The vision is for all residents to have reasonable access to an adequate, nutritious, and safe food supply, supported by a comprehensive network of food and nutrition services.

Self-Management in Nutrition

Concept and Components

Self-management is the ability to engage in daily tasks required to maintain health and well-being, or to manage chronic disease, based on knowledge and collaboration with healthcare teams.

• Includes patient education, person-centered care, health promotion, care coordination, collaboration, and addressing health disparities and equity.

Summary Table: Nutrient Categories and Functions

Nutrient	Main Function	Energy Value	Examples
Carbohydrates	Energy, metabolism	4 kcal/g	Bread, rice, fruits
Protein	Structure, function, repair	4 kcal/g	Meat, eggs, legumes
Fat	Energy storage, cell structure	9 kcal/g	Oils, nuts, butter
Vitamins	Regulation, metabolism	0 kcal/g	Fruits, vegetables
Minerals	Structure, regulation	0 kcal/g	Vegetables, dairy
Water	Transport, regulation	0 kcal/g	Water, fruits

Additional info: Academic context was added to clarify the role of nutrients, the impact of food environment, and the importance of self-management in health.