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Carbohydrates Functions: 1) Primary function = provide Energy 2) Structural components of body: I.e., cartilage 55- 60% of kcal of diet General Formula:

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Presentation on theme: "Carbohydrates Functions: 1) Primary function = provide Energy 2) Structural components of body: I.e., cartilage 55- 60% of kcal of diet General Formula:"— Presentation transcript:

1 Carbohydrates Functions: 1) Primary function = provide Energy 2) Structural components of body: I.e., cartilage % of kcal of diet General Formula: CH20

2 Classes of Carbohydrates 1) Simple CHO’s Single or double sugar units (saccharides) 2) Oligosaccharides 3 to 10 saccharide units 3) Complex CHO’s Usu 1,000’s of saccharide units long

3 Simple CHO’s Complex CHO’s Monosaccharides –Glucose –Fructose –Galactose Disaccharides –Maltose –Lactose –Sucrose Starch Glycogen Fiber Oligosaccharides Inulin fructoligosaccharide

4 Simple CHO’s Almost exclusively in plant foods Found in fruits, sweets, milk and milk products, table sugar

5 Monosaccharides Simplest CHO’s Building blocks of all CHO’s Glucose: most common –aka dextrose, blood sugar Fructose: fruits, honey, high-fructose corn sugar Galactose: part of milk sugar (lactose)

6 Glucose Fructose Galactose -mildy sweet -hardly sweet-Intensely sweet

7 Glucose + glucose maltose Galactose + glucose lactose Glucose + fructose sucrose Disaccharides

8 Maltose Lactose Sucrose maltase lactase sucrase glucose + glucose galactose + glucose glucose + fructose

9 Complex CHO’s aka Polysaccharides Starch –In plant foods –major E reserve for plants –= glucose + glucose + glucose etc. –About 3,000 glucose’s bonded together 2 Forms of starch: –1) amylose –2) amylopectin

10 Amylose Straight chain of glucose’s  1--> 4 bonds OOOOOOO

11 Amylopectin Branched chains of glucose’s:  1--> 4 bonds  1--> 6 bonds at branch points OOOOOOO OO

12 Complex CHO’s aka Polysaccharides Glycogen –Animals synthesize this and store it in liver and muscle –= glucose + glucose + glucose etc. –  1-->4 bonds and  1-->6 bonds OOOOOOO OO

13 Amylopectin vs. Glycogen Made by plants Made by animals Branched VERY HIGHLY Branched  1 --> 4  1 --> 4  1-->6  1 --> 6

14 Protein Lipids Inorganic substances Lignin Cellulose Hemicellulose Pectins Gums Mucilages Algal polysaccharides Suberin Cutin Plant Cell Wall Non-cell wall plant parts Dietary Fiber

15 Complex CHO’s aka Polysaccharides Fiber –Cellulose = very common fiber –= glucose + glucose + glucose etc. –  1-->4 bonds Etc...

16 Fiber NO Human enzymes can break down fiber Bacterial enzymes in intestines can break down fiber

17 Dietary Fiber Soluble Insoluble Some Hemicellulose Pectin Gums Mucilages Lignin Cellulose Some Hemicellulose

18 Soluble Fibers adsorption or binding of  Fecal bile acids  Lipid absorption  Serum cholesterol Bile acids Lipid Minerals Altered mineral balance

19 Soluble Fibers Gel Formation  Transit Time  Nutrient Absorption  Gastric Emptying Slow Glucose Absorption Feeling of Fullness

20 Insoluble & soluble Fibers  Water-holding capacity  Fecal volume  Colon Transit Time (speed movemn’t thru gut)  Defecation Frequency (  constipation)

21 Insoluble & Soluble Fibers Fermentability/ Degradability  Colonic Na + and H 2 O absorption  2˚ bile acid synthesis Lactate GI Lumen acidification Short Chain Fatty Acids Inhibit Tumor Formation Enterocyte Energy Mucosal Cell Proliferation

22 Fiber in Foods: In general, whole, unprocessed foods contain more fiber than their processed versions Most fiber-rich foods have a mix of various types of fibers Require about 25 to 35 grams/day

23 Fiber in Foods: Processing of foods Apple = 5 g Applesauce = 2 g Apple juice = 0.2 g

24 Increasing Fiber in the Diet:  Consumption of veggies, fruits, beans, whole-grain products Whole fruits instead of fruit juice Use whole-grain flour instead of white flour Brown rice instead of white rice

25 Dilute CHO’s vs. Concentrated CHO’s Sugar in Fruit vs. Sugar in Candy This Sugar comes with Vitamins, Minerals and Fiber NO fiber or very little Typically few Vitamins and Minerals/kcal

26 Ingredients List: Sucrose Glucose Maltose Dextrose Fructose High-fructose Corn Syrup Brown Sugar Honey Confectioner’s Sugar Invert Sugar Levulose Raw Sugar Turbinado Sugar

27 Sugar Intake Guideline < 10% of total kcal This applies to concentrated refined sugars (I.e., candies, sweets),not fruits or milk products

28 Suggestions to Reduce Sugar Intake: Substitute Water or Fruit Juices for soft drinks Unsweetened cereals Reduce sugar in recipes Use sweet spices, I.e., allspice, anise, cinnamon, ginger, vanilla, coconut

29 Dental Caries Bacteria feast on sugars and release acids that decay tooth enamel Not only the amount of sugar eaten How much the food clings to teeth How frequently eaten Baby bottle syndrome

30 Digestion of CHO’s Digestion begins in mouth, w/ salivary amylase Fiber delays gastric emptying Pancreatic amylase Lactase, maltase, sucrase are brush border enzymes (made by sm. Intestines)

31 The Fate of CHO’s in your body : 1) satisfy immediate energy needs of all your cells 2) Extra CHO’s converted to glycogen and stored in muscles and liver 3) Extra CHO’s converted to fat in liver and stored in adipose cells

32 Maintaining Blood Glucose Levels Critical to maintain blood glucose Too low ---> shaky, weak, headache Too high ---> sleepy, chronically high causes organ damage

33 Eat a Meal  Blood Glucose Pancreas releases Insulin Liver picks up glucose Muscle picks up glucose Adipose picks Up glucose Results in  Blood Glucose

34 Fasted  Blood Glucose Pancreas releases Glucagon Liver breaks down glycogen Muscle breaks down glycogen Adipose releases fat Results in  Blood Glucose

35 When Blood Glucose is Low, A Snack with CHO, Fat and Protein is Best : CHO: good source of glucose and stimulates insulin secretion Protein: stimulates glucagon which opposes insulin to prevent the body cells from picking up too much glucose too fast Fat:slows digestion --> slows absorption

36  Serum Cholesterol: Strongest Hypocholesterolemic Effect: –Psyllium, Guar Gum, Oat Gum Moderate Hypocholesterolemic Effect: –Oat Bran, Soybean fibers No Hypocholesterolemic Effect: –Wheat, Corn, Rice Brans

37 Hypoglycemia Abnormally low blood glucose level Symptoms = Recommend:

38 Diabetes IDDM (insulin-dep. diabetes mellitus) Aka: juvenile onset, type I About 10% of all cases NIDDM (non-insulin dep. Diabetes mellitus) Aka: adult-onset, type II About 90% of all cases 2x the risk to heart dx. Majority obese - a major cause of blindness, kidney failure, amputations, male impotence

39 Diabetes Risk for Women: Overweight women 8 times more likely to get diabetes than normal weight women Obese women 20 times more likely to get diabetes than normal weight women Women who do ≥ 7 hours moderate exercise/wk, 30% lower risk than women who exercise < 1/2 hour / wk Diets: high fiber & PUFA’s, low in SFA and trans fats 50% lower risk NEJM, 2001, 345, 785, 829; J Nat Cancer Inst, 2001, 93, 937

40 Number of New Diabetes Cases (NIDDM) 0-19 years J Pediatr, 1996, 128,

41 Number of New Diabetes Cases (NIDDM) years J Pediatr, 1996, 128,

42 Percentage of New Diabetes (NIDDM) Cases, years J Pediatr, 1996,128,

43 Rising Incidence of NIDDM in Youth 0-19 year olds: –Before 1992, 3-4% of all new cases of diabetes were NIDDM –After 1992, 16% of all new cases of diabetes were NIDDM –4 - fold INCREASE year olds: –Before 1992, 3-4% of all new cases of diabetes were NIDDM –After 1992, 33% of all new cases of diabetes were NIDDM –10 - fold INCREASE

44 Increased risks for Diabetics: Hypertension Coronary Heart Disease Stroke Amputations Blindness Kidney, liver damage

45 Blood Glucose Levels: Normal: mg/dL of blood Below 40 mg/dL (2.2mmol/L) --> coma, seizure, death Above approx. 180 mg/dL (10 mmol/L) --> –Immediate effects: glycosuria, caloric loss, thirst, hunger –Chronic effects: renal, retinal, nerve, blood vessel damage

46 Blood glucose (mg/dL) Time (hours) 1 2 Diabetes Normal Reactive Hypoglycemia

47 Glycemic Index = a quantitative ranking of foods based on their postprandial blood glucose response (above fasting glucose) compared to a reference food The reference food is either: –White bread (50 g available cabohydrate) –Glucose (50 g)

48

49 Factors that affect a food’s GI Particle size: as particle size  :  GI Differences in cooking Starch composition: amylose v. amylopectin Fiber content Ripeness Food processing

50 Application of GI Diabetes: the GI helps in control of blood glucose and insulin responses Sports performance: Different GI foods more effectively replenish glycogen stores after exercise: High GI foods replenish glycogen better than low GI foods Appetite Research: Low GI foods produce greater satiety than high GI foods

51 Obese Children High GI meal (instant oatmeal) Low GI meal (steel cut oats) (Identical energy & macronutrient intake) Ad libitum energy consumption monitored throughout rest of day Energy intake 53% HIGHER in High GI group Result: Ludwig et al., Pediatrics, 1999, 103, E261-66


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