Nutrition Edited by K. Elder and J. Kalweit Edited (2010) by C. Mullin This lecture will cover the essential aspects of nutrition. The subject of nutrition is very deep so it cannot be expected for students to get all the information they need to know. This lecture should instill in them some basic information and motivate them to seek additional information on their own. Created by Gregory Welk Edited by K. Elder and J. Kalweit Edited (2010) by C. Mullin 2

Food Food is any substance that is ingested (“eaten”) and sustains life Food is usually grouped into the following categories: Meats and Alternatives Dairy Products Fruits and Vegetables Breads, Cereals, Rice and Pasta Fats, Oils and Sweets

Classes of Nutrients Nutrients are essential dietary factors Carbohydrates Proteins Fats Vitamins Minerals Water These are the 6 classes of nutrients. Each nutrient plays a different role and is required for life.

Types of Carbohydrates (2 types) Provide energy (E) for the body Simple Sugars Have 1-2 sugar molecules together (faster to digest) pop, candy, sweets, fruit Complex Carbohydrates Have 3+ sugar molecules (longer to digest) grains, vegetables, legumes There are two different types of carbohydrates. Simple and complex carbohydrates are both composed of glucose or fructose molecules but they differ in how they are put together. Simple carbohydrates exist as independent glucose or fructose molecules whereas complex carbohydrates are connected in chains. Because of these differences simple and complex carbohydrates are processed very differently by the body (discuss insulin effect from simple carbos) With the exception of fruit simple carbohydrates are typically known as “empty calories” because they contain nothing but calories. Complex carbohydrates, on the other hand, contain a variety of vitamins, minerals and fiber.

Explain the trend and suggest why it is happening. 20 40 60 80 100 C A R B O H Y D T E S SIMPLE COMPLEX 1910 1950 1980 P N 65% 35% 50% 45% 55% This chart shows the trends in carbohydrate consumption over time. Note the progressive decline in the consumption of carbohydrates

Types of Protein Sources of Protein Proteins are chains of amino acids Used in growth and repair of tissue Sources of Protein Animal (complete) everything our bodies need meats, dairy Vegetable (incomplete) need to combine to get a complete source beans, nuts, legumes, grains There are two primary sources of protein. Animal protein is considered “complete” because it has all of the essential amino acids and other non-essential ones. Vegetable protein is considered an “incomplete” source because it doesn’t contain all of the essential amino acids. This is why vegetarians must consume a variety of foods to get the protein they need. This slide shows conceptually how amino acids are linked together to make proteins. By linking the amino acids in different orders the protein takes on different properties.

Types of Fats Used as energy storage for the body Saturated -Solid at room temperature Animal sources Leads to increased cholesterol levels in blood Unsaturated -Liquid at room temperature Vegetable sources Linked to lowering cholesterol These are the major sources of fat in the body. The difference between saturated and unsaturated fats can be explained with the diagram. The diagram shows an unsaturated fat because the carbon chain can accept hydrogen bonds instead of the carbon-carbon double bond.

Low Fat?

List Ways that you can Reduce your Fat Consumption Low fat cooking methods Minimize processed foods Use better cuts of meats Use low fat alternatives Decrease use of condiments White rather than red meat Follow these steps to reduce fat content in the diet.

Burning Calories

Vitamins Used to regulate metabolism Two types: Fat Soluble – dissolved by and stored in fat - e.g. Vit A, K Water Soluble – dissolved in water, extra excreted in urine- e.g. Vit B, C Vitamins

Minerals Inorganic elements found in food that are essential to life processes e.g. Calcium, Potassium, Sodium, Phosphorus, Iron Minerals

Water Vital to life Drink 6-8 glasses a day Water is the most important nutrient in our diet. We would die much quicker without water than we would without food. Drink at least 8 glasses per day. 9

Functions of Water Comprises about 55-60 % of body weight Major part of blood plasma Lubricates joints Shock absorber in eyes, spinal cord, and amniotic sac (during pregnancy) Active participant in many chemical reactions Water serves a variety of functions in the body

Review

The Body’s Needs

The body’s energy needs Every individual has his or her energy requirements Basal metabolism - energy needed by the body to when at rest (heart, respiration, cellular activity. Physical activity – walking, running, moving Digestion and absorption- breaking down food

Daily Energy Requirements Depends on: Age Sex Weight Level of physical activity Overall state of health

Measuring Energy in Food SI unit = joule (J) More common = dietary calorie (Cal) 1 Cal = 4000 J OR 4 kilojoules (kJ) Avg teen girl requires between 1800 & 2400 Cal / 7200 & 9600 kJ per day Avg teen boy requires between 2200 & 3200 Cal / 8800 & 12800 kJ per day

Recommended Dietary Intake Protein PROTEIN (17% or 2g/kg) (varies by weight) Fat FAT (11% or 75g) Carbs CARBS (72% or 500g) Recommended levels

Function of Food Carbohydrates All food has a function. Different foods give us different nutrients and have different functions Nutrient Function Carbohydrates 1st energy source Fat 2nd energy source Protein 3rd energy source Heal and grow muscles/bones Vitamins, Minerals, Water (& Fibre) Regulate Metabolism

Regulate Metabolism: Rate the body digests foods Regulate Metabolism: Rate the body digests foods. Some foods increase met., while others lower it. Generally genetic and lowers with age

How can you make sure you are eating properly?

Canada’s Food Guide A government document designed to assist Canadians in making a more informed decision on food choices and combinations. If Canadians can be taught to eat healthy foods and exercise mildly, it will reduce the strain on the Health Care System that is in place (Medicare)

This is an additional image of the CFG

Reading Nutrition Labels By law, food labels must contain certain things. Some of the legal requirements are:

List of ingredients List starts with the ingredient of the largest amount and continues to the ingredient of the smallest amount. Must list (may contain...) for potential allergens like peanuts

Nutrition Label Only became law as of December 2005 Displays the nutritional information contained in the product in grams and % of the Recommended Daily Intake (RDI) that is in one serving of that product.

Nutrition Label looks like this Size of recommended portion Number of servings per package Calories per serving Amount of nutrients by weight and % of RDI % of RDI for vitamins

Energy Value of Foods

Caloric Content of Foods The energy that the body gets from food: Carbohydrates 4 cal/g 17 KJ/g Protein 4 cal/g 17 KJ/g Alcohol 7 cal/g 29 KJ/g Fats 9 cal/g 37 KJ/g This slide shows the calorie content of different food stuffs