The Carbohydrates Sugars Starches and Fibers Chapter 4 Introduction Brain Muscles Glucose Glycogen Sources of carbohydrates Fattening mistaken thinking Chemist s View of Carbohydrates Carbohydrate family Monosaccharides single Glucose fructose galactose Disaccharides pair Maltose sucrose lactose Polysaccharides long chains Chemist s View of Carbohydrates Monosaccharides three Same numbers and kinds of atoms Differing sweetness Glucose blood sugar Fructose fruit sugar Sweetest of the sugars Part of every disaccharide and poly Galactose not really accessible in food Only in a few foods Chemist s View of Carbohydrates Disaccharides Pairs of two monosaccharides Maltose glucose glucose Sucrose fructose glucose Lactose glucose galactose Hydrolysis and Condensation Chemist s View of Carbohydrates Polysaccharides Glycogen animal storage form of carbs The body breaks up glycogen into glucose to produce energy Starch plant storage from of carbs Chemist s View of Carbohydrates Polysaccharides Fibers Differ from starches Soluble fibers Insoluble fibers Functional fibers Resistant starches Phytic acid Carbohydrate Digestion Specific disaccharide enzymes Starts in mouth Small intestine Maltase Sucrase Lactase Large intestine Fibers Carbohydrate Absorption Active transport Glucose Galactose Facilitated diffusion Fructose Liver Conversion of fructose and galactose Lactose Intolerance Lactase activity Symptoms of intolerance Causes of intolerance beyond age Prevalence Lactose Intolerance Dietary changes Individualized diets Potential nutrient deficiencies Lactose in Selected Foods Carbohydrate Metabolism Glucose is key player Storing glucose as glycogen stored in liver and muscles Liver storage Condensation into glycogen to store Hydrolysis for release of glucose when needed for energy Muscle storage they don t share Selfishly hoards glycogen Carbohydrate Metabolism Glucose for energy Gluconeogenesis the making glucose from protein Carbohydrate Metabolism Ketone bodies Fat metabolism shifts Ketone bodies form Ketosis acid base balance body becomes acidic CHO needs for protein sparing and prevention of ketosis 50 100 g daily Using glucose to make fat extra glucose fat storage is unlimited The Constancy of Blood Glucose Steady supply in blood stream of glucose Intestines small mainly glucose from food Liver converts glucose into glycogen Blood glucose homeostasis Insulin signals glucose to move from blood into cells Glucagon epinephrine are hormones that signal glucose to come out of liver glucagon when BG is low epinephrine with stress The Constancy of Blood Glucose Balancing within the normal range Balanced meals at regular intervals not fasting Diabetes Type 1 diabetes Type 2 diabetes Hypoglycemia low blood sugar Symptoms fatigue passing out crankiness The Constancy of Blood Glucose Glycemic response Speed of glucose absorption level of blood glucose and return to normal glucose levels High low glycemic response Glycemic index Alternative Sweeteners Artificial sweeteners Non nutritive sweeteners no kcal Large doses and adverse effects Stevia an herbal product Generally recognized as safe GRAS Sugar alcohols Provide kcalories less than sugar Benefits gum and side effects laxative effect Health Effects of Starch and Fibers Heart disease Whole grains contain soluble fibers Diet composition for reducing heart disease risk Health Effects of Starch and Fibers Diabetes GI health Cancer Weight management Health Effects of Starch and Fibers Excessive fiber Insufficient energy or nutrient needs Abdominal discomfort gas diarrhea GI obstruction Nutrient absorption can become blocked Dietary goals Balance moderation variety Characteristics Sources Health Effects of Fibers Recommended Intakes of Starch Fibers DRI for carbohydrates 45 to 65 of energy requirement carbs RDA for carbohydrates 130 grams per day Fiber guidelines Fiber in Selected Foods Fibers in Selected Foods From Guidelines to Groceries Grains 1 ounce provides about 15g of carbohydrate Vegetables Starch content Fruits Milk and milk products Protein foods no carbs From Guidelines to Groceries Read food labels Total carbohydrate Starch fibers sugars Sugars Added and natural sugar Bread Labels Compared Carbs kCalories and Controversies Highlight 4 Carbohydrates kCalorie Contributions Obesity and the link to carbohydrates Total daily energy intakes have increased Activity levels have declined Increase in body weight Epidemiological studies Inverse relationship between carbs weight Weight loss kCalorie intake Energy Nutrients over Time Daily Energy Intake Increases in Adult Body Weight over Time Sugars Share in the Problem Increase in consumption of added sugars High fructose corn syrup does not cause you to release insulin Body fat stores Carbohydrate cravings Self imposed labeling of foods Carbohydrate addictions Not physiological or pharmacological Sugars Share in the Problem Appetite control Fructose and insulin Flaws in plausibility Food form liquid or solid Simple to swallow Energy regulation Insulin s Response Surge of insulin levels Glycemic effect Factors impacting glycemic effect Glycemic index and body weight Insulin resistance Fructose Prediabetes and metabolic syndrome Body s insulin response
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