Carbohydrates 4 5 4 7 4 9 4 10 and Nutrition and your Health Section January 21st 2011 Carbohydrates in Foods Starches and fiber Grains Fruits fiber Starchy Vegetables Starch and fiber Milk lactose Digestion of Carbohydrates GOAL 1 Break down CHO into smallest parts monosaccharides 2 Absorb 3 Convert to glucose for energy Digestion of Carbohydrate Mouth Salivary amylase Partial digestion of starch Breaks starch to shorter saccharides Prolonged chewing Short duration in mouth Stomach Acidic environment HCl No further starch digestion salivary amylase inactivated Digestion Small Intestine Food enters from stomach pyloric sphincter Hormone secretin is secreted in presence of CHO Pancreas produces pancreatic amylase Digests starch to di saccharides ex maltose Enzymes on intestinal wall Maltase sucrase lactase Split dissaccharides to monosaccharides Absorption of monosaccharides on intestinal wall villi microvilli enter circulation to liver Presence of fiber slower digestion absorption Carbohydrate Digestion Effects of Cooking Softens fibrous tissues Easier to chew and swallow Lactose Maldigestion Reduction in lactase Lactose is undigested and not absorbed Lactose is metabolized by large intestinal Causes gas bloating cramping discomfort Primary lactose maldigestion Secondary lactose maldigestion Severe cases are called lactose intolerance What To Do if You Have Lactose Maldigestion or Lactose Intolerance Determine amount you can tolerate Eat dairy with fat Cheese yogurt are usually well tolerated Use Lact Aid Absorption of Carbohydrates Glucose and Galactose Active absorption Energy is expended Fructose Facilitated absorption using a carrier No energy expended Fate of Glucose liver and beyond Portal Circulation to liver Used for energy immediately after absorption Glucose released into bloodstream from liver Protein sparing Prevents ketosis Stored as glycogen future energy Liver 1 3 and Muscle 2 3 Converted to fat When would this happen Carbohydrate Needs RDA is 130 grams day for adults Average U S intake is 180 330 grams Recommendations vary FNB 45 65 of total calories Nutrition Facts panel 60 Dietary Guidelines Focus on fruits vegetables whole grains Recommended Dietary Fiber Intake DRI 14 g 1000 kcal day 28g day for 2000 diet DV is 25 grams for 2000 kcal diet AI is 25 grams day for women 38 grams day for men ADA 20 35g day Average U S intake 13 grams day for women 17 grams day for men ADA American Dietetic Association Too Much Fiber 60 grams day Extra fluid needed May decrease availability of some minerals Unmet energy needs in children Recommendation for Simple Sugar Intake added sugars Low nutrient density Dental caries Added to food and beverages 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 82 grams per day High fructose Corn Syrup 55 fructose Cornstarch mixed with acid and enzymes Starch is broken down to glucose Some glucose is converted to fructose Cheaper than sucrose Does not form crystals Other Types of Sweeteners Brown sugar Turbinado sugar raw sugar Maple syrup Honey Sugar alcohols sorbitol xylitol 2 6 kcal g partially digested Absorbed and metabolized slower Excess consumption may have a laxative effect Sugar Substitutes not gonna be on our test yeah yeah Sugar Alcohols Sorbitol Xylitol 2 6 kcals gram Large quantities can cause diarrhea Do not promote tooth decay Saccharin First produced in 1879 180 200x sweeter than sucrose No potential risk in humans Sweet and Low Aspartame Equal NutraSweet Composed of phenylalanine aspartic acid and methanol 180 200x sweeter than sucrose 4 kcal gm Not heat stable 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 Warning label for Phenylketonuria PKU Sucralose Splenda 600x sweeter than sucrose Substitutes chlorines for hydroxyl groups on sucrose Heat stable Tiny amount digested Excreted in the feces Neotame FDA approved for general purpose sweetener Similar structure to Aspartame Is not broken down in the body 7 000 13 000x sweeter than sucrose Heat stable Safe for use Acesulfame K Sunette Approved by FDA 200x sweeter than sucrose Not digested by the body Heat stable Diabetisweet used in baking Tagatose Altered form of fructose 1 5 kcals gram Does not increase glucose level Does not cause tooth decay Is fermented by large intestine Stevia Sweet Leaf 100 300X sweeter than sucrose Provides no energy Generally recognized as safe GRAS Can not be used as additive in food products CARBOHYDRATE METABOLISM Carbohydrate short supply Make glucose from protein Gluconeogenesis Make ketone bodies from fat Ketosis Acid base balance Regulation of Blood Glucose Blood glucose remains within healthy ranges Fasting 70 100 mg dl Post Prandial 140 mg dl Hyperglycemia high blood sugars Hypoglycemia low blood sugars Blood Glucose Control Role of the liver Regulates glucose that enters bloodstream Role of the pancreas Release of insulin Release of glucagon Adrenal Gland ephinephrine Regulating hormones Insulin Secreted after meal Increases glucose uptake by cells Promotes glycogen synthesis Reduces gluconeogenesis Net effect Lowers BG Glucagon Epinephrine Secreted when blood glucose BG gets low Summons glucose from storage glycogen Enhances gluconeogenesis Net effect raises BG Net effect Fight or flight Summons glucose quickly when Raises BG stressed Breakdown of glycogen Overview of Diabetes Mellitus DM 1 Type 1 DM T1DM early onset genetic 2 Type 2 DM T2DM majority of people 3 Gestational Diabetes GDM Group of disorders characterized by Elevated blood glucose concentrations Disordered insulin metabolism Unable to secrete sufficient insulin use insulin effectively or both Overview of Diabetes Mellitus Insulin secreted by the pancreas normally Increases after ingestion of food energy between meals in smaller amounts restrain the glucose raising actions of glucagon and the breakdown of glycogen Overview of Diabetes Mellitus In diabetes Insulin secretion by pancreatic beta cells may be impaired Body attacks pancreas and renders beta cells useless Type 1 Pancreas overexerts itself because of insulin resistance and over time Type 2 Cells that are normally responsive to insulin may become resistant to its effects insulin resistance hallmark of Type 2 DM This leads to Hyperglycemia Type 1 DM pancreas does not secrete insulin glucose builds up in the blood cells think they are starving
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