1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 04 *Lecture Outline *See separate Image PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes.

Photosynthesis

Monosaccharides Simple sugar units Simple sugar units Glucose Glucose Fructose Fructose Galactose Galactose

Glucose Major monosaccharide in the body Major monosaccharide in the body Also known as dextrose Also known as dextrose In bloodstream called blood sugar In bloodstream called blood sugar Breakdown of starches and sucrose Breakdown of starches and sucrose Source of fuel for cells Source of fuel for cells

Fructose (fruit sugar) In sucrose In sucrose In fruit, honey, and high-fructose corn syrup In fruit, honey, and high-fructose corn syrup Converted into glucose in the liver Converted into glucose in the liver

Galactose In lactose In lactose Converted to glucose in the liver Converted to glucose in the liver

Disaccharides

Disaccharides “Simple sugars” “Simple sugars” Sucrose (Glucose + Fructose) Sucrose (Glucose + Fructose) –Sugar Lactose (Galactose + Glucose) Lactose (Galactose + Glucose) –Milk products Maltose (Glucose + Glucose) Maltose (Glucose + Glucose) –Fermentation –Alcohol production

Complex Carbohydrates Polysaccharides: Starch & Glycogen Polysaccharides: Starch & Glycogen Amylose Amylose Amylopectin Amylopectin Dietary fiber Dietary fiber

Polysaccharides: Starch 3,000 or more monosaccharides 3,000 or more monosaccharides Starch Starch –Amylose--straight chain polymer –Amylopectin--highly branched polymer

Common Starches

Glycogen Storage form of carbohydrate for animals and human Storage form of carbohydrate for animals and human Structure similar to amylopectin Structure similar to amylopectin More sites for enzyme action More sites for enzyme action Found in the liver and muscles Found in the liver and muscles

Dietary Fiber Undigested starch Undigested starch Body cannot break the bonds Body cannot break the bonds Insoluble or Non-fermentable fiber Insoluble or Non-fermentable fiber –Cellulose, hemicellulose, lignin –Not fermented by the bacteria in the colon Soluble or Viscous fiber Soluble or Viscous fiber –Gum, pectin, mucilage –Fruit, vegetable, rice bran, psyllium seed

Functional Fiber Fiber added to food Fiber added to food –Provides health benefits Prebiotics – Type of functional fiber Prebiotics – Type of functional fiber –Stimulate growth or activity of beneficial bacteria in the large intestine

Viscous and Non-Fermentable Fiber

Benefits of Dietary Fiber

Carbohydrates in Foods Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. MyPlate: Sources of Carbohydrates Grains Vegetables Fruits Dairy Protein 15 grams per serving 5 grams per serving 18 grams per serving Milk Yogurt Beans Nuts 12 grams per serving 4-10 grams per serving Choose Myplate.gov All varieties (grains): Keith Weller/USDA; (vegetables): © Mitch Hrdlicka/Getty Images RF; (fruits): © Ingram Publishing/SuperStock RF Grains Fruits Protein Vegetables Dairy Grains Fruits Protein Vegetables Dairy

Sweeteners

High-fructose Corn Syrup Made from corn Made from corn 55% fructose 55% fructose Cornstarch mixed with acid and enzymes Cornstarch mixed with acid and enzymes Starch is broken down to glucose Starch is broken down to glucose Some glucose is converted to fructose Some glucose is converted to fructose Improved shelf-stability and food properties Improved shelf-stability and food properties

Other Types of Sweeteners Brown sugar Brown sugar Turbinado sugar (raw sugar) Turbinado sugar (raw sugar) Maple syrup Maple syrup Honey Honey

Sugar Alcohols Sorbitol, Xylitol Sorbitol, Xylitol ~2.6 kcals/gram ~2.6 kcals/gram “Excess consumption may have a laxative effect” “Excess consumption may have a laxative effect” Do not promote tooth decay Do not promote tooth decay

Sugar Substitutes

Saccharin ( Sweet ‘N Low  ) First produced in 1879 First produced in x sweeter than sucrose x sweeter than sucrose No potential risk in humans No potential risk in humans

Aspartame (Equal , NutraSweet  ) Composed of phenylalanine, aspartic acid, and methanol Composed of phenylalanine, aspartic acid, and methanol x sweeter than sucrose x sweeter than sucrose 4 kcal/gm – only small amount needed 4 kcal/gm – only small amount needed Not heat stable Not heat stable Complaints of sensitivity Complaints of sensitivity –Headaches, dizziness, seizures, nausea, etc. Acceptable daily intake: 50 mg per kg body weight (FDA) (~14 cans of diet soda for average adult per day) Acceptable daily intake: 50 mg per kg body weight (FDA) (~14 cans of diet soda for average adult per day) Warning label for Phenylketonuria (PKU) Warning label for Phenylketonuria (PKU)

Sucralose ( Splenda  ) 600x sweeter than sucrose 600x sweeter than sucrose Substitutes chlorines for hydroxyl groups on sucrose Substitutes chlorines for hydroxyl groups on sucrose Heat stable Heat stable Tiny amount digested Tiny amount digested Excreted in the feces Excreted in the feces

Neotame FDA approved for general-purpose sweetener FDA approved for general-purpose sweetener Similar structure to Aspartame Similar structure to Aspartame Is not broken down in the body Is not broken down in the body 7,000-13,000x sweeter than sucrose 7,000-13,000x sweeter than sucrose Heat stable Heat stable Safe for use Safe for use

Acesulfame-K (Sunette  ) Approved by FDA Approved by FDA 200x sweeter than sucrose 200x sweeter than sucrose Not digested by the body Not digested by the body Heat stable Heat stable Can be used in baking Can be used in baking

Tagatose (Naturlose  ) Altered form of fructose Altered form of fructose 1.5 kcals/gram 1.5 kcals/gram Does not increase glucose level Does not increase glucose level Does not cause tooth decay Does not cause tooth decay Is fermented by large intestine Is fermented by large intestine

Stevia (Sweet Leaf ® ) X sweeter than sucrose X sweeter than sucrose Provides no energy Provides no energy Generally recognized as safe (GRAS) Generally recognized as safe (GRAS) Can not be used as additive in food products Can not be used as additive in food products

Carbohydrate Digestion

Effects of Cooking Softens fibrous tissues Softens fibrous tissues Easier to chew and swallow Easier to chew and swallow

Digestion of Carbohydrate in the Mouth Salivary amylase Salivary amylase –Breaks starch to shorter saccharides –Prolonged chewing Short duration in the mouth Short duration in the mouth

Digestion of Carbohydrate in the Stomach Acidic environment Acidic environment No further starch digestion No further starch digestion

Digestion of Carbohydrate in the Small Intestine Pancreas releases enzymes Pancreas releases enzymes –Pancreatic amylase Absorptive cells release Absorptive cells release –Maltase –Sucrase –Lactase Monosaccharides are absorbed Monosaccharides are absorbed

Carbohydrate Digestion

Lactose Maldigestion Reduction in lactase Reduction in lactase –Lactose is undigested and not absorbed –Lactose is metabolized by large intestinal bacteria  Causes gas, bloating, cramping, discomfort Primary lactose maldigestion Primary lactose maldigestion Secondary lactose maldigestion Secondary lactose maldigestion Severe cases are called lactose intolerance Severe cases are called lactose intolerance

What To Do if You Have Lactose Maldigestion or Lactose Intolerance Determine amount you can tolerate Determine amount you can tolerate Eat dairy with fat Eat dairy with fat Cheese & yogurt are usually well tolerated Cheese & yogurt are usually well tolerated Use Lact-Aid  Use Lact-Aid 

Absorption Glucose and Galactose Glucose and Galactose –Active absorption –Energy is expended Fructose Fructose –Facilitated absorption using a carrier –No energy expended

After Absorption Portal vein to the liver Portal vein to the liver Liver can: Liver can: –Transform monosaccharide into glucose –Release glucose back into the bloodstream –Store as glycogen (or fat)

Undigested Carbohydrates Only a minor amount escapes digestion Only a minor amount escapes digestion Travels to the colon Travels to the colon Fermentation by the bacteria Fermentation by the bacteria Acids and gases produced are absorbed Acids and gases produced are absorbed May promote health of the colon May promote health of the colon

Functions of Carbohydrate Supplies energy Supplies energy Protein sparing Protein sparing Prevents ketosis Prevents ketosis

Regulation of Blood Glucose Hyperglycemia Hyperglycemia Hypoglycemia Hypoglycemia

Blood Glucose Control Role of the liver Role of the liver –Regulates glucose that enters bloodstream Role of the pancreas Role of the pancreas –Release of insulin –Release of glucagon

Functions of Insulin Promotes glycogen synthesis Promotes glycogen synthesis Increases glucose uptake by the cells Increases glucose uptake by the cells Reduces gluconeogenesis Reduces gluconeogenesis Net effect: lowers blood glucose Net effect: lowers blood glucose

Functions of Glucagon Breakdown glycogen Breakdown glycogen Enhances gluconeogenesis Enhances gluconeogenesis Net effect: raises blood glucose Net effect: raises blood glucose

Epinephrine / Adrenaline “Fight or flight” response “Fight or flight” response Breakdown glycogen Breakdown glycogen Raises blood glucose Raises blood glucose

Regulation of Blood Glucose

Glycemic Response Glycemic Index Glycemic Index –Ratio of blood glucose response to a given food Glycemic Load Glycemic Load –Grams of carbohydrate in a food multiplied by the glycemic index of that food –Divide result by 100

High Glycemic Load Large release of insulin Large release of insulin –Increase blood triglycerides level –Increase fat deposits –Increase clotting –Increase fat synthesis in liver –Rapid return of hunger Insulin resistance develops (Type 2 diabetes) Insulin resistance develops (Type 2 diabetes)

Dietary Fiber and Health

Hemorrhoids Swelling of a large vein Swelling of a large vein Result from excessive straining Result from excessive straining

Diverticula

Colon Cancer and Fiber Controversial Controversial Focus on fruits, vegetables, beans, and whole grains Focus on fruits, vegetables, beans, and whole grains Higher-fiber foods are more nutrient dense Higher-fiber foods are more nutrient dense

Reducing Obesity Risk Filling Filling Low in kcal Low in kcal Satisfied after eating Satisfied after eating

Enhancing Glucose Control Soluble fiber slows glucose absorption Soluble fiber slows glucose absorption Better blood glucose regulation Better blood glucose regulation

Cholesterol and (Soluble) Fiber Absorption of cholesterol inhibited Absorption of cholesterol inhibited Bile acid absorption reduced Bile acid absorption reduced Risk for cardiovascular disease and gallstones reduced Risk for cardiovascular disease and gallstones reduced Insulin release decreased Insulin release decreased –Decrease cholesterol synthesis in the liver Blood cholesterol lowered Blood cholesterol lowered

Carbohydrate Needs RDA is 130 grams/day for adults RDA is 130 grams/day for adults Average U.S. intake is grams Average U.S. intake is grams Recommendations vary Recommendations vary –FNB: 45%-65% of total calories –Nutrition Facts panel: 60% Focus on fruits, vegetables, whole grains Focus on fruits, vegetables, whole grains

Recommended Dietary Fiber Intake AI is 25 grams/day for women AI is 25 grams/day for women AI is 38 grams/day for men AI is 38 grams/day for men Goal of 14 grams/1000 kcal Goal of 14 grams/1000 kcal DV is 25 grams for 2000 kcal diet DV is 25 grams for 2000 kcal diet Average U.S. intake: Average U.S. intake: –14 grams/day for women –17 grams/day for men

Too Much Fiber > 60 grams/day > 60 grams/day Extra fluid needed Extra fluid needed May decrease availability of some minerals May decrease availability of some minerals Unmet energy needs in children Unmet energy needs in children

Recommendation for Simple Sugar Intake Low nutrient density Low nutrient density Dental caries Dental caries Added to food and beverages Added to food and beverages < 10% of total kcal/day with a maximum of 50 grams (12 tsp) per day--WHO < 10% of total kcal/day with a maximum of 50 grams (12 tsp) per day--WHO Average U.S. intake: 16% of total kcal/day Average U.S. intake: 16% of total kcal/day –~82 grams per day

Dietary Sources of Added Sugars Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Soda, energy drinks, sports drinks 35.7% Grain-based desserts 12.9% Fruit drinks 10.5% Dairy desserts 6.5% Candy 6.1% Ready-to-eat cereals 3.8% Sugars and honey 3.5% Tea 3.5% Yeast breads 2.1% All other food categories 15.4%

Diabetes Type 1 Diabetes Type 1 Diabetes Type 2 Diabetes Type 2 Diabetes Gestational Diabetes Gestational Diabetes

Glucose Tolerance Test

Type 1 Diabetes Occurs often in children Occurs often in children Genetic link Genetic link Body stops producing insulin Body stops producing insulin Treatment Treatment –Insulin Therapy –Diet Therapy

Type 2 Diabetes Generally in people > 40 years of age Generally in people > 40 years of age Increasing rates in younger individuals Increasing rates in younger individuals Obesity Obesity Treatment Treatment –Weight loss –Oral medications –Diet therapy –Insulin

Hypoglycemia Reactive hypoglycemia Reactive hypoglycemia –Occurs 2-4 hours after eating a meal –Possibly due to over-secretion of insulin Fasting hypoglycemia Fasting hypoglycemia –Usually caused by pancreatic cancer –Leads to overproduction of insulin

Metabolic Syndrome (Syndrome X) 25% of adults have it 25% of adults have it High blood triglycerides High blood triglycerides Poor blood glucose regulation Poor blood glucose regulation Hypertension Hypertension Risk factors Risk factors –Obesity –Lack of physical activities –High simple/refined sugar intake –Low fiber intake

Metabolic Syndrome (Syndrome X) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Metabolic Syndrome Risk Indicators High blood pressure 130/85 mmHg or higher Low HDL cholesterol Men with HDL level less than 40 mg/dl Women with HDL level less than 50 mg/dl Elevated glucose Fasting level of 100 mg/dl or higher Elevated triglycerides (blood fat) 150 mg/dl or higher Abdominal obesity Men with waist circumference greater than 40 inches Women with waist circumference greater than 35 inches Medical Conditions Related to Metabolic Syndrome Type 2 diabetesCoronary artery diseaseStroke Over time, insulin resistance can increase blood glucose levels, which can lead to type 2 diabetes. Elevated blood pressure and cholesterol levels can cause plaque to build up inside coronary arteries, which may eventually lead to a heart attack. Plaque buildup in arteries can lead to blood clots that prevent blood flow to the brain, causing damage to brain tissue.