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Chapter 4: Sugars, Starches and Fibers Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. Student learning outcomes: At the end of this chapter, you should be able to: Compare and contrast whole grains and refined sugars Compare and contrast types of carbohydrates Describe the role of carbohydrates in health and disease Plan a diet to meet carbohydrate recommendations © 2012 John Wiley & Sons, Inc. All rights reserved. THINK about this – then share within a PAIR – then SHARE with the class What do you know about sugars, starches, and fibers? What are whole grains and refined sugars? How whole grains and refined sugars important for your health? © 2012 John Wiley & Sons, Inc. All rights reserved. Whole grains vs. refined grains Whole grains: contain the whole kernel, including the brain, germ, and endosperm Refined grains: foods processed to remove course parts such as the bran and germ which removes the fiber and some vitamins and minerals © 2012 John Wiley & Sons, Inc. All rights reserved. Whole grains vs. refined grains © 2012 John Wiley & Sons, Inc. All rights reserved. Enrichment Legislation requires the fortification of grains with some of the nutrients removed during processing © 2012 John Wiley & Sons, Inc. All rights reserved. Enrichment © 2012 John Wiley & Sons, Inc. All rights reserved. Empty calories Refined sugars contain calories but lack fiber and other nutrients Sugars from whole foods such as fruit and vegetables are more nutrient dense © 2012 John Wiley & Sons, Inc. All rights reserved. Empty calories © 2012 John Wiley & Sons, Inc. All rights reserved. Concept check How are whole grains and refined sugars similar and different? How are hole grains and refined sugars important for your health? © 2012 John Wiley & Sons, Inc. All rights reserved. Concept check In a refined grain, which part remains? a) b) c) d) Germ Bran Endosperm All of the above © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrates Carbohydrates (CH2O) n C = carbo; H2O = hydrate Simple Complex Polysaccharides (poly means many) Disaccharide (di means two) Monosaccharide (mono means one) Animal Storage Glycogen Lactose Galactose Plant Storage Starch Maltose Glucose Plant Structure Fiber Sucrose Fructose Soluble Insoluble © 2012 John Wiley & Sons, Inc. All rights reserved. Disaccharides vs. Monosaccharides © 2012 John Wiley & Sons, Inc. All rights reserved. Complex carbohydrates Excess glucose is linked together for storage Glycogen: storage in animal skeletal muscles and the liver Starch: storage in plants Fiber: a different type of bond links glucose molecules to make plant support structures Humans cannot break this type of bond © 2012 John Wiley & Sons, Inc. All rights reserved. Complex carbohydrates Glycogen Starch Fiber © 2012 John Wiley & Sons, Inc. All rights reserved. Excess glucose in animals Glycogen: limited storage polymer of glucose in skeletal muscles and liver Once glycogen storage capacity reached then glucose must be converted into fat Fat: unlimited storage in adipose tissue © 2012 John Wiley & Sons, Inc. All rights reserved. Complex carbohydrates © 2012 John Wiley & Sons, Inc. All rights reserved. Photosynthesis sunlight C6H12O6 + O2 CO2 + H2O energy carbon + water glucose + oxygen dioxide Starch Fiber © 2012 John Wiley & Sons, Inc. All rights reserved. Photosynthesis © 2012 John Wiley & Sons, Inc. All rights reserved. Soluble fiber vs. insoluble fiber Soluble fiber: Dissolves in water Partially digested by bacteria in large intestine Helps lower cholesterol Examples: pectins, gums, & some hemicelluloses © 2012 John Wiley & Sons, Inc. All rights reserved. Soluble fiber vs. insoluble fiber Insoluble fiber: Does not dissolve in water Not digested by bacteria in large intestine Examples: cellulose, some hemicelluloses, & lignin © 2012 John Wiley & Sons, Inc. All rights reserved. Soluble fiber vs. insoluble fiber © 2012 John Wiley & Sons, Inc. All rights reserved. What are similarities and differences between: Glucose and maltose? Maltose and starch? Starch and fiber? Starch and glycogen? Glucose and glycogen? © 2012 John Wiley & Sons, Inc. All rights reserved. Concept check Amylase breaks down starch into which disaccharide? a) b) c) d) Glycogen Maltose Glucose Sucrose © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrate digestion © 2012 John Wiley & Sons, Inc. All rights reserved. Lactose intolerance Low levels of small intestine enzyme lactase The disaccharide lactose cannot be broken down into monosaccharides Lactose passes into the large intestines where it is digested by bacteria Symptoms: gas, abdominal distension, cramping, diarrhea Obtain calcium from: tofu, legumes, dark green vegetables, canned salmon and sardines, calciumfortified foods, calcium supplements, lactasetreated milk © 2012 John Wiley & Sons, Inc. All rights reserved. Lactose intolerance © 2012 John Wiley & Sons, Inc. All rights reserved. Indigestible carbohydrates Fiber: not broken down by human enzymes Oligosaccharides: 3–10 sugar units; some are not broken down by human enzymes Resistant starch: natural structure of the grain protects the starch molecules or cooking and processing alter digestibility Examples: legumes, unripe bananas, and cold cooked potatoes, rice, and pasta © 2012 John Wiley & Sons, Inc. All rights reserved. Indigestible carbohydrates © 2012 John Wiley & Sons, Inc. All rights reserved. Indigestible carbohydrates © 2012 John Wiley & Sons, Inc. All rights reserved. Glycemic index vs. load vs. response Glycemic index: ranking of how a food affects blood glucose relative to an equivalent amount of carbohydrate from a reference food, such as white bread or pure glucose Examples: white bread = 100, kidney beans = 25 © 2012 John Wiley & Sons, Inc. All rights reserved. Glycemic index vs. load vs. response Glycemic load: compares the effect of typical portions of food on blood glucose Glycemic response: measures how quickly and how high blood glucose levels rise after carbohydrate consumption © 2012 John Wiley & Sons, Inc. All rights reserved. Glycemic index © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrate functions Energy! Lactose: used by nerve cells and to make milk Ribose & deoxyribose: in DNA & RNA Ribose: in B vitamin riboflavin Cell membrane signaling Cushioning and lubrication © 2012 John Wiley & Sons, Inc. All rights reserved. Insulin vs. glucagon Increased blood glucose Decreased blood glucose Insulin secretion Glucose taken into cells Decreased blood glucose Glucagon secretion Glucose released from liver Increased blood glucose © 2012 John Wiley & Sons, Inc. All rights reserved. Insulin vs. glucagon © 2012 John Wiley & Sons, Inc. All rights reserved. Digestion & cellular respiration Starch amylase Maltose amylase C6H12O6 + O2 glucose + oxygen CO2 + H2O + ATP carbon + water + energy dioxide © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrate metabolism Glucose (6 carbons) Aerobic (requires oxygen) Glycolysis Anaerobic (without oxygen) Mitochondria Pyruvate (3 carbons) Cytosol Cellular Respiration Carbon dioxide 32-36 ATP per glucose Lactic Acid Fermentation Lactic acid © 2012 John Wiley & Sons, Inc. All rights reserved. 2 ATP per glucose Cellular respiration © 2012 John Wiley & Sons, Inc. All rights reserved. Protein & fat breakdown © 2012 John Wiley & Sons, Inc. All rights reserved. Ketones Ketones or ketone bodies = acidic molecules produced by fat breakdown when carbohydrates are not available to cells Heart, muscle and kidneys use for energy Brain adapts after 3 days to use ketones Produced with starvation, low-carb diets, diabetes © 2012 John Wiley & Sons, Inc. All rights reserved. Ketones Ketosis: increased ketones in blood Ketoacidosis: acidic blood from increased ketones © 2012 John Wiley & Sons, Inc. All rights reserved. Concept check Which hormone is secreted when blood glucose is low? a) b) c) d) Insulin Glycogen Ketones Glucagon © 2012 John Wiley & Sons, Inc. All rights reserved. THINK about this – then share within a PAIR – then SHARE with the class What do you know about diabetes? © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus Diseases characterized by high blood glucose Type I: decreased insulin secretion Autoimmune destruction of insulin-secreting cells in the pancreas Type II: insulin resistance Gestational: first observed during pregnancy © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus signs & symptoms High blood glucose since insulin does not signal cells to take up glucose Causes weight loss since the body breaks down fat Causes increased hunger © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus signs & symptoms Increased glucose in urine Water tries to dilute glucose causing increased excretion of water causing dehydration and thirst Blurred vision Water tries to dilute glucose in the eye © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus complications © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus management Control blood sugar levels Limit carbohydrate intake Increase whole grains, decrease refined sugars Type I & some Type II patients need insulin injections Type II patients often take oral drugs © 2012 John Wiley & Sons, Inc. All rights reserved. Diabetes mellitus management Exercise Exercise and weight loss in Type II helps prevent, reverse, and manage the disease Low saturated fat, low trans fat, low cholesterol © 2012 John Wiley & Sons, Inc. All rights reserved. What are similarities and differences between: Insulin and glucagon? Type I and Type II diabetes? © 2012 John Wiley & Sons, Inc. All rights reserved. Hypoglycemia Low blood sugar levels Caused by: Overmedication with insulin Abnormal insulin or other hormone secretion or response © 2012 John Wiley & Sons, Inc. All rights reserved. Hypoglycemia Fasting hypoglycemia: when a person has not eaten and usually has some other condition Reactive hypoglycemia: too much insulin response after a highcarbohydrate meal © 2012 John Wiley & Sons, Inc. All rights reserved. Dental caries (cavities) Bacteria in mouth digest carbohydrates and produce acid which damages tooth enamel Increased risk: Increased intake of sucrose and starch Frequent exposure © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrates & calorie intake © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrates & weight loss © 2012 John Wiley & Sons, Inc. All rights reserved. Debate Should You Avoid High-Fructose Corn Syrup? © 2012 John Wiley & Sons, Inc. All rights reserved. Nonnutritive (artificial) sweeteners Replace sugar in the diet Pros and cons: + + − − − Decrease dental caries Control blood sugar Associated with weight gain Present in low nutrient density foods Toxic at high doses © 2012 John Wiley & Sons, Inc. All rights reserved. Cardiovascular disease High-sugar diets increase blood lipids High blood glucose damages blood vessels Soluble fiber decreases cholesterol absorption and synthesis High-fiber diets decrease blood pressure, weight, blood glucose, and heart disease Diets high in fruits and vegetables increase fiber and protective antioxidants © 2012 John Wiley & Sons, Inc. All rights reserved. Soluble fiber & cholesterol © 2012 John Wiley & Sons, Inc. All rights reserved. Bowel health High-fiber diets decrease: Constipation (if adequate water is consumed) Hemorrhoids (varicose veins in the anus and rectum) Diverticula (outpouching of the large intestines) Colon cancer?? © 2012 John Wiley & Sons, Inc. All rights reserved. Diverticulosis © 2012 John Wiley & Sons, Inc. All rights reserved. Applications What advice could you give to a loved on about carbohydrate consumption to decrease disease risk? © 2012 John Wiley & Sons, Inc. All rights reserved. Carbohydrate recommendations Enough carbohydrate to meet glucose needs Choosing types for health & disease prevention RDA for carbohydrate =130 g/day Acceptable Macronutrient Distribution Range for carbohydrate = 45–65% of total calorie intake Adequate Intake for fiber = 38 g/day for men & 25 g/day for women © 2012 John Wiley & Sons, Inc. All rights reserved. How much carbohydrate do you eat? © 2012 John Wiley & Sons, Inc. All rights reserved. Calculate Total calories = 3000 Total carbohydrates = 500 grams Carbohydrates = 4 calories/gram Fiber = 20 grams Does this diet meet the RDA and AMDR for carbohydrate intake and the AI for fiber? © 2012 John Wiley & Sons, Inc. All rights reserved. Put it together What is the percentage of calories from carbohydrate in a diet that provides 240 grams of carbohydrate and 2400 Calories? a) b) c) d) 10 40 50 60 © 2012 John Wiley & Sons, Inc. All rights reserved. Thinking it through © 2012 John Wiley & Sons, Inc. All rights reserved. Choosing carbohydrate wisely 2010 Dietary Guidelines and MyPlate: increase whole grains, fruits and vegetables, and reduced-fat dairy products limit foods high in refined grains and added sugars Dietary Guidelines specifically recommend reducing intake of sugar-sweetened beverages © 2012 John Wiley & Sons, Inc. All rights reserved. Choosing carbohydrate wisely MyPlate recommends for a 2000 calorie diet 6 oz of grains (half should be whole grains) 2 cups of fruit 21/2 cups of vegetables © 2012 John Wiley & Sons, Inc. All rights reserved. ChooseMyPlate.gov © 2012 John Wiley & Sons, Inc. All rights reserved. Interpreting food labels © 2012 John Wiley & Sons, Inc. All rights reserved. Interpreting food labels © 2012 John Wiley & Sons, Inc. All rights reserved. Interpreting food labels © 2012 John Wiley & Sons, Inc. All rights reserved. Nutrition in the news Low-carb diets High-fructose corn syrup Vending machines in schools Artificial sweeteners Taxes on sugar-sweetened beverages © 2012 John Wiley & Sons, Inc. All rights reserved. Checking student learning outcomes How are whole grains and refined sugars similar and different? How do they contribute to health and disease? How are types of carbohydrates similar and different? What advice would you give to a loved one about carbohydrate consumption? © 2012 John Wiley & Sons, Inc. All rights reserved.
