EPHE 155 Introduction to Nutrition: Past Paper Spring 2025

EPHE 155 Introduction to Nutrition: Concepts & Controversies Macronutrients - Carbohydrate University of Victoria, School of Exercise Science, Physical and Health Education Dr.Kimberly McQueen, BSc ND Email: [email protected] Learning Goals...

EPHE 155 Introduction to Nutrition: Concepts & Controversies Macronutrients - Carbohydrate University of Victoria, School of Exercise Science, Physical and Health Education Dr.Kimberly McQueen, BSc ND Email: [email protected] Learning Goals ❏ Describe the major types of carbohydrates, and identify foods that are sources of carbohydrates. ❏ Describe the role of carbohydrates in the body ❏ Identify key differences between fibre and other types of carbohydrates. ❏ Explain how carbohydrates are broken down and absorbed in the body. ❏ Discuss the body's management glucose.  Vegetables Fruit Food Sources of Carbohydrates Whole Grains Carbohydrates Simple Carbohydrates Complex Carbohydrates 6 molecules in this group includes, Glycogen, Starch, and Fibre Chemical name ends in -ose Classified as Polysaccharides Classified as Monosaccharides and Disaccharides Simple Carbohydrates AKA Simple Sugars Table sugar is sucrose The words sugar can be used to mean table sugar, or glucose (in the body) Sugars can be naturally occuring in a food, or added in food processing Complex Carbohydrates Key Differences between Fibre and other Carbs Human digestion can not break the bonds in WHO (World Health Organization) fibre and so it yields little to no energy recommends more than 25g of fibre per day directly. However, digestive microbes can, ferment Health Canada recommends this AI fibre, to varying degrees, and produce SCFA (Adequate Intake): (Short Chain Fatty Acids) - butyrate, Women age 19-50: 25g propionate and acetate. These SCFA are used Women age 51+: 21g as a fuel by digestive cells and contribute to Men age 19-50: 38g good digestive health. Men age 51+ 30g Two main categories of fibres: 1. Soluble -absorbs water. Thickens 1. Insoluble -does not absorb water. Maintains shape Soluble and Insoluble Fibre Known Health benefits of Fibre Heart and Metabolic Health: Reduces the risk of heart disease, promotes normal blood cholesterol levels, and helps modulate blood glucose concentrations. Digestive Health: Supports gut microbiota, promotes regular bowel movements, and reduces the risk of constipation, hemorrhoids, diverticulosis, appendicitis, and colon cancer. Weight Management: Enhances satiety, helping to regulate appetite and prevent overeating. These benefits are mutually supportive, fostering a positive cycle of improved health and well-being across multiple systems. Cautions Digestive Issues: Too much fibre can cause bloating, gas, cramping, or diarrhea. Purified Fibers: Added fibres (e.g., inulin) may cause digestive discomfort in high amounts. Nutrient Absorption: Some compounds, like phytates and oxalates, naturally found in seeds, grains, and legumes, can reduce mineral absorption (e.g., calcium, iron) by binding to the mineral. This has given them the name anti-nutrients. However, proper preparation (e.g., soaking, sprouting, cooking) can minimize this effect by breaking down phytic acid, and remember that these compounds are naturally occurring.. Dehydration Risk: Soluble fibre absorbs water—insufficient hydration can lead to constipation.  Whole Grains The kernel is the part of the plant that can be milled into Whole Grain = the whole flour. kernel/seed minus the husk Its processing determines Refined = the process of removing the outcome: will it remain a the course parts of the grain whole grain or be refined? In refined wheat flour: The Kernel: Only the endosperm is 1. The Germ = nutrient rich, can retained. germinate into new plant, The husk, bran, and rich in vitamin and minerals germ are removed. 1. The Endosperm = contains starch and protein 1. The Bran = protective fibrous coating (comparable to the shell of a nut) 1. The Husk = indedible Terms that describe grain food Bread Brown bread = bread is brown colour, and may be made with any flour. The brown colour may be from molasses being added Stone ground = refers to a milling process using limestone. It can be any type of grain, including refined Unbleached flour = endosperm flour with texture and nutrient qualities similar to regular white flour Wheat flour = a flour made from wheat White flour = a refined endosperm flour that is bleached for maximum softness and whiteness Whole-wheat flour = flour made from whole wheat kernels, a whole-grain flour Digestion and Absorption of Carbohydrates Glucose Best known for its role in providing energy to most cells Body handles glucose judiciously ○ Maintains an internal supply ○ Tightly controls blood glucose concentrations At the Cell - Glucose Inside the cell glucose is broken in half, or lysed to release energy. This process is called glycolysis They can then either be put back together to create glucose again or broken into smaller pieces The smaller fragments can ○ yield even more energy by entering the Krebs cycle and the electron transport chain Glucose Storage The Liver, Muscle and Brain cells use some of the incoming glucose to build glycogen (the polysaccharide, storage form of carbohydrate). Muscles conserve glycogen for their own use - and hoard most of the body’s glycogen (2/3rds of it) The Liver is generous with its glycogen. If needed, Liver enzymes attack the ends of the highly branched glycogen to quickly release glucose back into the system to support other cells. This can happen in response to a drop in blood sugar, and signalled by the release of glucagon from the pancreas. The Liver stores enough glycogen to cover about 3-6 hours The Brain reserves a tiny amount of glycogen to cover its needs for 1-2 hours, in case severe deprivation occurs Blood Glucose Regulation Hypothalamus Role: The hypothalamus monitors blood glucose levels and signals the pancreas to respond as needed. Pancreas Response: Rise in Blood Glucose (BG): ○ The pancreas secretes insulin, prompting cells to take up glucose from the blood for energy or storage. Fall in Blood Glucose (BG): ○ The pancreas releases glucagon, signaling the liver to break down glycogen and release glucose into the bloodstream. Below a minimum The minimum daily intake of Carbohydrate has been set at 130g of digestible carbohydrate. Below a Healthy Minimum the body: Turns to protein to make Carb -so to be adequately nourished with carbohydrate, spares protein for its more important functions Changes Fat metabolism -fat fragment combine with each other to form Ketone bodies (vs combining with CHO) and this creates ketosis In a land of Glucose plenty Once muscle and liver glycogen stores are saturated, if there is still plenty of glucose available then the body prioritizes burning glucose over fat for energy. As a result, excess fat remains in circulation and is stored in adipose (fat) tissue. Liver’s Role: The liver converts excess glucose into fat, which is then sent to fat cells for storage. Fat Cells’ Role: If glucose levels remain high, fat cells also convert glucose into fat. This process requires multiple energy-intensive enzymatic steps. Glycemic Index & Glycemic load Glycemic Index (GI) measures how quickly a food raises blood sugar compared to glucose. Glycemic Load (GL) factors in both GI and carbohydrate content for a practical blood sugar impact measure. Managing GI/GL can support diabetes control and reduce insulin needs. Diabetes Prevalence of Diabetes A Leading Health Concern: One of the top 10 causes of death among adults. Canadian Impact: An estimated 2.4 million Canadians were living with diabetes as of 2016. Common Forms of Diabetes 1. Type 1 Diabetes: Autoimmune condition requiring insulin therapy. 2. Type 2 Diabetes: Often linked to lifestyle factors; can be managed with diet, exercise, and medication. 3. Gestational Diabetes: Develops during pregnancy and increases the risk of Type 2 diabetes later. 4. Type 3 Diabetes (Proposed):T Emerging research suggests a possible link between insulin resistance and dementia. Where do we find Carbohydrates Whole-Grain Foods Choose low-fat and low-sugar options to maximize nutrient density. Vegetables Non-Starchy Vegetables: Contain lower amounts of carbohydrates (e.g., leafy greens, peppers). Starchy Vegetables: Provide higher carbohydrate content (e.g., potatoes, corn). Fruits Vary in water, fiber, and sugar concentrations. Juice: A concentrated source of sugar with little to no fiber—limit intake or dilute with water. Non-Meat-Based Protein Foods Examples: Nuts, dried beans, and legumes contain both protein and carbohydrates. Milk and Milk-Substitute Protein Foods Look for higher protein options (e.g., Greek yogurt or fortified plant-based milk). Consider lower-fat choices to manage overall calorie intake. Sugary Drinks Contain added sugars and contribute to excess calorie intake without providing fiber or significant nutrients. Minimize consumption. Oils and Fats Do not contain carbohydrates. Naturally Occurring vs. Added Sugars Focus on foods with naturally occurring sugars (e.g., fruits, dairy) over those with added sugars. Sugars  Carbohydrate Targets Total Carbohydrate: AMDR (Acceptable Macronutrient Distribution Range) is 45-65% of calories DRI (Dietary Reference Intake) is 130g minimum My working target is 5-12g/kg Fibre: Women age 19-50 DRI: 25g Women age 51+ DRI: 21g Men age 19-50 DRI: 38g Men age 51+ DRI: 30g WHO (World Health Organization): 25g Added sugar Less that 10% of daily calories (keeping to 5% of daily calories might have added health benefits) The World Health Organization defines sugars as the mono- and disaccharides added by cooks, consumers, and food manufacturers, as well as the sugars found in honey, syrup, fruit juice, and fruit concentrates. For example, if your recommended intake is 2,500 Calories, 10% of that would be 250 Calories. Since each gram of sugar provides 4 Calories, dividing 250 Calories by 4 Calories per gram means your sugar intake should be 62 grams or less.