Carbohydrates Learning Session Notes Spring 20 PDF

01/27/2020 CARBOHYDRATES Learning Objectives 1. Identify primary monosaccharides and disaccharides in foods and dietary sources of each. 2. Define nutritive and non-nutritive sweeteners and provide examples of each. 3. List potential negative health impacts of nutritiv...

01/27/2020 CARBOHYDRATES Learning Objectives 1. Identify primary monosaccharides and disaccharides in foods and dietary sources of each. 2. Define nutritive and non-nutritive sweeteners and provide examples of each. 3. List potential negative health impacts of nutritive sweeteners. 4. List and describe the types of complex carbohydrates. 1  01/27/2020 Learning Objectives 5. Identify components of whole grains and list the components removed during processing. 6. Define gluconeogenesis and ketosis. 7. Discuss the roles of insulin and glucagon in regulating blood glucose. 8. Describe the three categories of diabetes mellitus and associated complications. Learning Objectives 9. Distinguish between soluble and insoluble fiber and resistant starch; List food sources and benefits of each. 10. Define celiac disease and identify foods appropriate for those with the disease. 11. Explain the etiology of tooth decay. 12. Discuss the pros and cons of low-carbohydrate diets. 13. Define lactose intolerance. 2  01/27/2020 Carbohydrates: A Diverse Class of Nutrients Carbohydrates are a diverse class of nutrients, and each specific carbohydrate has unique health properties Major function of carbohydrates: Supply energy or calories 4 kcal per gram AMDR: 45-65% of total daily calories How are carbohydrates produced? Carbohydrates are produced by photosynthesis in plants process in which carbon dioxide from the atmosphere, water from soil, and energy from the sun interact in a biochemical reaction to produce glucose 3  01/27/2020 How do we define a carbohydrate? Scientists coined the term carbohydrate based on its chemical composition Only three elements are contained Carbon Hydrogen Oxygen The term literally means “carbon with water” Types of carbohydrates Carbohydrates are chemically categorized as either simple or complex based on number of single units (monosaccharides) they contain Simple: less than 10 monosaccharide units Complex: more than 10 (up to thousands) units Chemical classification does not always help us understand health impact 4  01/27/2020 Simple carbohydrates: Monosaccharides Group of single sugar molecules used to assemble all carbohydrates Consists of one basic chemical ring Glucose Most common form Circulates in blood Fructose Found abundantly in fruits, honey Simple carbohydrates: Monosaccharides Galactose Rarely exists as individual compound in foods Component of lactose in milk Found in pectin and other dietary fibers http://www.danisco.com/product-range/pectin/ 5  01/27/2020 Simple carbohydrates: Disaccharides Composed of two monosaccharides linked together by a chemical bond Flavoring and Sweetening Foods Sweeteners used to flavor foods may be classified into two different categories. Non-nutritive sweeteners May be natural or synthetic and do not provide calories Aspartame (Equal) Acesulfame-K (Sunnett) Saccharin (Sweet’n Low) Sucralose (Splenda) 6  01/27/2020 Flavoring and Sweetening Foods Nutritive sweeteners Can be digested and yield calories Includes sucrose, fructose, honey, molasses, high fructose corn syrup Does high fructose corn syrup cause obesity? 55% fructose, 45 % glucose Found in many foods May contribute to excess calories Simple Carbohydrates: Flavoring and Sweetening Foods Is honey healthier for you than sugar? Honey is composed of fructose and glucose Reduced impact on blood glucose Has 21 kcal per teaspoon vs 15 kcal per teaspoon for table sugar Not recommended for infants may contain Clostridium botulinum spores 7  01/27/2020 Complex Carbohydrates Polysaccharides Composed of chain with thousands of glucose molecules linked together 1. Starch The storage form of carbohydrate found in plants Generally either long, straight chains or are branched chains Complex Carbohydrates 2. Glycogen Storage form of carbohydrate found in liver and muscle of animals DietaryFiber Composed of repeating units of glucose and other monosaccharides that cannot be digested by human enzymes 8  01/27/2020 Recommended carbohydrate intake Types of carbohydrates consumed may affect health. The minimum carbohydrate intake to spare protein and avoid ketosis is about 130 g/day Complex carbohydrates recommended: Whole grains Vegetables Fruit Legumes Nuts and seeds Recommended carbohydrate intake What are whole grains? All components of grain kernel present Endosperm Bran Germ 9  01/27/2020 Recommended carbohydrate intake Refinedgrains germ and bran removed nutrients lost o fiber o B-vitamins o healthy fats o some minerals: iron, magnesium Enrichment of refined grains Thiamin, riboflavin, niacin, *folic acid, iron What are primary sources of carbohydrates? Sugar comprises ~25% of total calorie intake in Western diets Sugars in foods may occur naturally or can be added to a food product: How to know if food has added sugars? Look at ingredient list 10  01/27/2020 Dietary role of carbohydrates Speed with which we obtain energy depends on how quickly digestion occurs o Simple sugars easily digested and absorbed quick energy source o Slowly digested and absorbed carbohydrates provide a sustained level of energy Protein sparing Sufficient amount of carbohydrates consumed - proteins and amino acids spared for growth and repair Insufficient amount of carbohydrates consumed - body begins to use protein as a source of energy Gluconeogenesis The synthesis of new glucose from non- carbohydrate sources 11  01/27/2020 Preventing ketosis Fat, carbs, and protein converted to acetyl CoA, which is eventually broken for energy Oxaloacetate a chemical derived from carbohydrates and certain amino acids needed to fully break down fats Ketone bodies Acidic fat byproducts that arise from the incomplete breakdown of fat Ketosis Acid-base imbalance, dehydration, dizziness, fainting Regulating blood glucose levels Normal blood glucose levels: 70-99 mg/dL After eating foods with carbohydrates o Blood glucose elevated Long periods between meals o Blood glucose drops The body has mechanisms to maintain a stable level of glucose in the blood using hormones: oinsulin o glucagon and epinephrine 12  01/27/2020 Regulating blood glucose levels The fate of glucose due to insulin: o Meet immediate energy needs o If glucose concentrations exceed energy requirements 1. Stored as glycogen in liver and muscle 2. Stored as fat The fate of glucose due to glucagon: o Glycogen broken down for glucose o Triggers gluconeogenesis Regulating blood glucose levels When blood When blood glucose glucose elevates normalizes When blood When blood glucose glucose drops normalizes 13  01/27/2020 Glycemic Response Glycemic index measure of how fast blood glucose levels rise after ingestion of a food compared to ingestion of glucose. For a single food eaten alone, not as part of meal Glycemic load mathematical score that adjusts glycemic index to the total carbohydrate in a mixture of food consumed Do low glycemic index foods help with weight loss? - No strong, research-based evidence in literature Glycemic Index of Common Foods Diabetes Care 31:2281–2283, 2008 14  01/27/2020 CARBOHYDRATES: In Health and Disease Diabetes Mellitus Diabetes mellitus (DM) o inability of the body to regulate blood glucose levels within normal limits Hyperglycemia o elevated blood glucose Categories of diabetes: o Type 1 diabetes mellitus o Type 2 diabetes mellitus o Gestational diabetes mellitus 15  01/27/2020 Categories of diabetes Pre-diabetes o state of impaired glucose tolerance leading to elevated blood glucose; left untreated, can progress to diabetes Type 1 Diabetes Mellitus o Most often diagnosed in children or adolescents o Pancreas is unable to produce insulin o It is thought to be an autoimmune disease Categories of diabetes Type 2 Diabetes Mellitus oAccounts for more than 90% of all cases of diabetes mellitus o Cells are insulin resistant o Typically over age 40 and overweight or obese when diagnosed - Increasing numbers of diagnosis at younger ages 16  01/27/2020 Differences in ethnicities of DM diagnosis Source: National Diabetes Statistics Report. CDC. http://www.cdc.gov/diabetes/pubs/statsreport14/national-diabetes-report-web.pdf. Risk factors for Type 2 DM Overweight or obese Older age Prior elevated glucose Family history – close relative with type 2 DM Previous gestational DM diagnosis or have given birth to infant > 9 pounds Physical inactivity Polycystic ovary syndrome Acanthosis nigricans 17  01/27/2020 Complications of diabetes Water loss as kidneys try to eliminate excess glucose Increased risk for coronary heart disease Kidney disease High blood pressure Damage to the eyes and blood vessels o blindness Damage to nervous system otingling and numbness Gestational diabetes Type of diabetes that occurs in some women during pregnancy. Resolves after pregnancy Complications for infant: o can cause fetal or infant illness or death o high birth weight (macrosomia) of infant o low blood glucose post-delivery o diagnosis of DM later in life 18  01/27/2020 Gestational diabetes Complications for mother: oGreater likelihood of developing DM within 5 to 10 years Geneticsusceptibility: o Hispanics and Native Americans have higher susceptibility Dietary fiber Resistant to digestion by human enzymes Associated with the prevention of several chronic diseases Mostly composed of polysaccharides o exception is lignin; not technically a carbohydrate A more accurate term to use instead of dietary fiber is non-starch polysaccharide 19  01/27/2020 Dietary Fiber Two types o Soluble fiber o Insoluble fiber 1. Soluble fiber o can dissolve in water o jellylike material that acts like a cement in plants o Health benefits: Binds to bile in intestine Can aid in lowering blood cholesterol May reduce risk of heart disease Soluble Fiber o Common dietary sources Fruit Legumes Oat bran Potatoes Peas 20  01/27/2020 Dietary Fiber 2. Insoluble fiber o cannot be dissolved in water o composed of cellulose, hemicellulose, and lignin o May soften stools and accelerate passage of contents through the gastrointestinal tract decreasing transit time Insoluble Fiber Common dietary sources: oCereals oWhole grains oWheat bran oLegumes oBrown rice 21  01/27/2020 Health Benefits of Dietary Fiber Assists with bowel regularity oReduced constipation oHemorrhoids Reduces risk of diverticulosis Reduces contact of toxic materials with intestinal wall oReduced risk of colon cancer May aid in weight control Reduces risk of heart disease Improves blood glucose control Dietary fiber intake Need to increase fiber slowly in diet o Drink adequate fluids Overconsumption of fiber carries some health risks o Decreased absorption of some minerals: calcium, zinc, copper, and iron Excess fiber intake causes an increased number of bowel movements o diarrhea and dehydration 22  01/27/2020 Is there a problem with wheat? Some of the most widely consumed grains in the United States are wheat, rye and barley Grains provide o fiber o calories o protein o micronutrients Is there a problem with wheat? Some people have intolerance to the protein gluten. Celiac disease: intolerance to gluten that results in autoimmune response o Flattens inside of intestinal wall oReduces ability to absorb some nutrients o Response to gluten from: wheat, barley, rye and some oats oTreatment: Eliminate sources of gluten from diet 23  01/27/2020 Sugar Intake and Dental Decay Process by which dietary sugar can lead to dental decay o carbohydrate can adhere to enamel of teeth o bacteria metabolize carbohydrate in mouth o lactic acid produced by bacterial fermentation degrades tooth enamel allows for further bacterial infiltration and growth Prevention Adequate oral hygiene Fluoridation of water Low-Carbohydrate Diets and Weight Loss Low-carbohydrate diets proposed as a great way to lose weight oForces fat to be metabolized for energy, producing ketones o Muscle glycogen also broken down to glucose Water is released when glycogen broken down 24  01/27/2020 Low Carbohydrate Diet and Weight Loss Low-carbohydrate diets also high in fat, particularly saturated fat o Potential increased risk for heart disease Low-carb diets associated with various issues: o Bad breath due to increase of ketone bodies o Constipation due to low dietary fiber intake o Dehydration from induced water loss o Difficult to maintain long-term Lactose Intolerance Lactoseis the sugar in milk and milk products o Galactose and glucose o Disaccharide must be broken down to be absorbed Some people unable to digest lactose due to loss of function of enzyme lactase: o Lactose intolerance May be due to genetics, aging, illness, or medications Symptoms include: o diarrhea, bloating, and flatulence 25  01/27/2020 Lactose Intolerance *May not need to avoid lactose entirely: oSmallerportions at one time oLactose-hydrolyzed milk oYogurt o Lactase drops or pills *Soy milk and other non-dairy milk alternatives 26