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Carbohydrates, Chapter 4

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1 Carbohydrates, Chapter 4
Patty Maloney MSN/Ed,RN

2 Key Concepts Carbohydrate foods provide energy (calories)
Carbohydrates are readily available and usually low cost Carbohydrate structures vary from simple to complex to provide both quick and extended energy for the body. What are some of the staple carbohydrates in a diet? Wheat, corn, rice

3 Key Concepts Carbohydrates = Primary fuel source,
Major source of ENERGY Carbohydrates – break down rapidly The term energy is used interchangeably with calorie, kilocalorie, kcal

4 Carbohydrates Carbon Hydrogen Oxygen

5 Carbohydrates Are widely available and easily grown
Relatively low in cost May be easily stored Approximately ½ of total calories in American diet come from carbs.

6 Carbohydrates To produce energy, the body: 1. Digests the carbohydrate (fuel) and changes it to glucose 2. Absorbs and carries this fuel to cells in need 3. Energy is burned and released Share these facts with the students: In the typical American diet, half of total caloric intake is in the form of carbohydrates. Daily intake of sugars by Americans accounts for 20% to 40% of total caloric intake. Ask the students what some of the major sources of sugars are in their own diets.

7 Carbohydrates Copyright © 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved.

8 Classes of Carbohydrates
Monosaccharides (one molecule C6H12O6) Disaccharides (two molecules C6H12O6) Polysaccharides

9 Classes of Carbohydrates
Monosaccharides – building block of all carbs Simple, single sugar Simple carbohydrate Glucose (also known as dextrose) supply comes from digestion of starch All sugars convert to glucose in the blood Fructose Found in fruits, honey – very sweet High fructose corn syrup – soda, canned goods, processed foods Galactose From digestion of milk sugar CHO – CHEMICAL NATURE = CARBON, HYDROGEN, OXYGEN MONOSACCHARIDES = BUILDING BLOCKS FOR ALL CARBOHYDRATES ABSORBED FROM INTESTINE INTO THE BLOOD STREAM AND STORED IN LIVER AS GLYCOGEN (THIS STORAGE PROVIDES CONSTANT BACKUP SUPPLY OF ENERGY ***GLUCOSE = PRIMARY FUEL FOR CELLS, SUPPLY OF GLUCOSE COMES FROM DIGESTION OF STARCH – NOT USUALLY FOUND IN DIET, EXCEPT CORN SYRUP OR SOME PROCESSED FOODS ***FRUCTOSE = FOUND IN FRUITS AND HONEY ***HIGH FRUCTOSE CORN SYRUP = INEXPENSIVE, USED MORE OFTEN NOW IN SODAS, CANNED GOODS, PROCESSED FOODS ***GALACTOSE = COMES FROM DIGESTION OF MILK, SUGAR OR LACTOSE Figure information: From Mahan LK, Escott-Stump S: Krause’s food, nutrition, & diet therapy, ed 11, Philadelphia, 2004, Saunders.

10 Classes of Carbohydrates, cont’d
Disaccharides Double sugar Simple carbohydrate Sucrose – table sugar Powdered, granulated, brown sugar Lactose Sugar found in milk Maltose Not found in diet, results as a breakdown product of starch Used as a sweetener Found in beer, malt products, infant formula Which one of these is commonly known as table sugar? SUCROSE – GRANULATED, POWDER, OR BROWN SUGAR ***MADE FROM SUGAR CANE OR SUGAR BEETS LACTOSE = SUGAR IN MILK, FORMED IN MAMMARY GLANDS, LESS SWEET THAN SUCROSE MALTOSE = NOT FOUND IN THE DIET, RESULTS AS A BREAKDOWN PRODUCT OF STARCH, SYNTHETICALLY PRODUCED AND USED AS A SWEETENER Explain that maltose can be found naturally in foods such as beer but that most often it is an intermediate disaccharide that results from the digestion of starch. Figure information: From Mahan LK, Escott-Stump S: Krause’s food, nutrition, & diet therapy, ed 11, Philadelphia, 2004, Saunders.

11 Classes of Carbohydrates, cont’d
Polysaccharides = complex carbs Starch Glycogen Dietary fiber POLYSACCHARIDES = COMPLEX CARBS, MADE UP OF MANY SINGLE-SUGAR UNITs ***STARCHES BREAK DOWN SLOWLY IN THE BODY – BROKEN DOWN SOONER THROUGH COOKING/HEATING PROCESS Ask the students to name sources of starch. Grains (cereal, pasta, bread, crackers), legumes (beans, peas), potatoes, rice, corn Does cooking the starch before eating it make it more digestible? YES

12 Starch Legumes = beans, peas, lentils
Most important polysaccharide in the diet - Sources (grains, legumes,potatoes,rice) - Complex CHO Legumes = beans, peas, lentils Enriched grains are refined grains that have nutrients added back to them (ie: iron, riboflavin, vitamin A) Whole grains – keep outer bran layer, high fiber MOST IMPORTANT DIETARY CHO - WORLDWIDE COMPLEX CHO - STARCHES BREAK DOWN SLOWLY IN THE BODY - BUT ARE BROKEN DOWN SOONER DURING COOKING/HEATING PROCESS SOURCES OF STARCH – GRAINS (CEREAL, PASTA, BREAD, CRACKERS), LEGUMES (PEAS, BEAN), POTATOES, RICE, CORN REMEMBER – 45-65% TOTAL CALS. SHOULD COME FROM CHO – MAJORITY FROM COMPLEX CHO’S – WHOLE GRAINS BEST !! - WHOLE GRAIN – UNREFINED GRAINS – KEEP OUTER BRAN LAYER = FIBER NUTRIENTS Name sources of whole grains and mention the marketing done by food manufacturers and stores to promote whole grain consumption. What vitamins and minerals have been added to enriched grains that are normally not found in significant amounts? Iron, calcium, folate

13 Kernel of Wheat Figure information:
Kernel of wheat showing bran layers, endosperm, and germ. Courtesy Eileen Draper.

14 Glycogen Not a significant CHO source in the diet
Storage form of carbohydrates in the body – for about 24 hours, stored in the liver and muscles. Stored in liver & muscles – it is “recycled” Storage form of quick energy Helps to maintain normal blood sugar throughout day & night GLYCOGEN IS FOUND IN LIVER/MUSCLE WHERE IT IS RECYCLED - IT IS BROKEN DOWN TO FORM GLUCOSE FOR IMMEDIATE ENERGY GLYCOGEN HELPS TO MAINTAIN A NORMAL BLOOD SUGAR THROUGHOUT DAY & NIGHT (EVEN WHILE ASLEEP, FASTING) WILL LEARN MORE RE: GLYCOGEN CH. 20

15 Fiber Type of polysaccharide Soluble (helps to lower cholesterol & weight) Beans, oatmeal, barley, broccoli, citrus fruits Insoluble (provides bulk in GI tract) Stems/leaves of vegetables, bran, whole grains Indigestible carbohydrate – humans lack enzyme needed to digest fiber Important for digestion and health of GI tract (gastrointestinal) Fiber is important for health promotion and disease prevention – especially GI, CV, and diabetes management FIBER DOES NOT HAVE A DIRECT ENERGY VALUE, BUT OTHER DIETARY ASSETS ! (AS ABOVE) SOLUBLE FIBER (WATER SOLUBLE) = BINDS BILE ACIDS AND LOWERS CHOLESTEROL – CERTAIN PLANTS, SEAWEED, FRUITS INSOLUBLE FIBER = IMPORTANT FOR CONSTIPATION – PROVIDES BULK – STEMS/LEAVES OF VEGETABLES, BRAN, WHOLE GRAIN NAME DIETARY SOURCES OF FIBER – bran cereals, whole wheat bread, air popped popcorn, black beans, asparagus, cauliflower, green peas, Raisins, apples – see page 20 in book for list of dietary fiber


17 FIBER Recommended daily intake = Men – 38 grams Women – 25 grams
Reduced for people over 50 yrs. – Men – 30 grams Women – 21 grams

18 Sweeteners Nutritive sweeteners Nonnutritive sweeteners
Sugar alcohols (sorbitol, mannitol, xylitol) Have caloric value Nonnutritive sweeteners Artificial sweeteners in food (aspartame, saccharin) Have no caloric value SWEETENERS = CHO – EITHER NUTRITIVE OR NON-NUTRITIVE Do sugar alcohols provide the same amount of energy as other carbohydrates? Because sugar alcohols are absorbed more slowly from the gut than are other carbohydrates, how would this affect blood glucose levels? Nonnutritive sweeteners are hundreds of times sweeter than table sugar. Explain how adding a minute amount can sweeten a food.

19 Function of Carbohydrates
Basic fuel supply Energy for physical activities and all work of body cells Reserve fuel supply Provided by glycogen Maintains normal blood glucose level Carbohydrates burn in the body at rate of 4 kcal/g. RESERVE FUEL SUPPLY = FROM GLYCOGEN (LIVER,MUSCLE) – NEED TO REFUEL BY EATING CHO REGULARLY – THIS HELPS TO AVOID DRAMATIC CHANGES IN BLOOD GLUCOSE LEVELS OTHERWISE, ENERGY COMES FROM BREAKDOWN OF PROTEIN IN THE MUSCLE Explain this in terms of work: 30 minutes jogging burns approximately 200 calories. How many grams of carbohydrate would be needed to provide that energy? 50 g How many pieces of bread would a person need to eat to get 50 g? 3-4 pieces Explain the process of blood glucose level variance and homeostasis. The body regulates blood glucose to keep all cells provided with energy at all times.

20 Special Tissue Functions of Carbohydrates
Liver Stores glycogen - to protect cells from depressed metabolic function Back up energy source Protein and fat Carbohydrates protect (regulate) proteins and fat – allows them to be used properly for tissue building Spares body protein from being used for energy The protein-sparing function of carbohydrates protects proteins, allowing them to be used for tissue growth and maintenance. Carbohydrates prevent the rapid breakdown of fats that would produce excess amounts of ketones. What would happen without reserve stores of glycogen? - breakdown of protein (muscle) and fat (tissues), altered blood glucose Which is used first to maintain blood glucose levels, liver or muscle glycogen?

21 Special Tissue Functions of Carbohydrates, cont’d
Heart Glycogen is vital emergency fuel for heart muscle Central nervous system Brain dependent on minute-to-minute supply of glucose Enhances learning and memory HEART MUSCLE SUSTAINS LIFE ! FATTY ACIDS ARE MAIN FUEL SUPPLY OF HEART – GLYCOGEN IS EMERGENCY FUEL BRAIN HAS NO STORED SUPPLY OF GLUCOSE – NEEDS IT FROM BLOOD SUPPLY Low blood sugar may cause brain damage and death. What type of effects would be seen in someone who cannot regulate blood glucose normally and therefore has low levels for an extended amount of time (e.g., diabetics)?

22 Food Sources of Carbohydrates
Starches Provide important complex carbohydrates, key to a good diet ! Important source of fiber Sugars High-sugar diets carry health risks Average American eats 10 tablespoons per day ***REVIEW TABLE 2.5 RE: CHO FOODS ! EXAMPLES -----CHO CONTENT OF FOODS (GRAMS PER SERVING) – ½ MED. TOMATOE = 2.4 GM, 1/2C. CHEDDAR = .7GM, 1 CUP LETTUCE = 1 G., *****SUGARS INCLUDE: GLUCOSE, SUCROSE (TABLE), FRUCTOSE, LACTOSE (IN MILK), MALTOSE TSP. SUGAR = 4.2 GM, HIGH FRUCTOSE CORN SYRUP = 14.5 GM, 1 C. SKIM MILK = 12 GM., 1 C. PASTA = 39 GM, 1 SLICE WHITE BREAD 12 GM 1 OZ. SQUARE BROWNIE = 18GM, SODA (COLA) = 35 GM, 1 PKG. SKITTLES 2OZ = 52 GM, 1 PACKAGE (5 OZ) DRIED FRUIT = 93 GM AVERAGE AMERICAN EATS 10 TABLESPOONS OF ADDED SUGAR PER DAY What risks are associated with high-sugar diets? Explain that one of the easiest steps someone dieting can take is to cut sugared drinks from the diet.

23 Food Sources of Carbohydrates
1 slice white bread 12 grams 1 cup pasta grams 1 cup skim milk 12 grams 1 soda (cola) 35 grams Skittles (2 oz.) 52 grams Dried fruit (5 oz.) 93 grams 1 tsp. sugar grams RDA = grams per day

24 High Fructose Corn Syrup
Sweetener – from corn Average annual intake = 60 lb. per person Increases triglycerides and body fat Leads to increased cravings


26 Body Needs for Carbohydrates
Dietary Reference Intakes 45% to 60% of adult’s total caloric intake should come from carbohydrate foods Approximately gm per day Limit sugar to no more than 25% of calories consumed Dietary Guidelines for Americans, 2005 General guidelines: fiber rich foods, whole grains, reduced sugar or no-added sugar, non-caloric sweeteners, oral hygiene GUIDELINES ENCOURAGE THE FOLLOWING: CHOOSE FIBER RICH FRUITS, VEGETABLES AND WHOLE GRAINS CHOOSE FOODS WITH LITTLE OR NO ADDED SUGAR – CHOOSE NON-CALORIC SWEETENERS GOOD ORAL HYGIENE TO REDUCE DENTAL CARRIES – LESS SUGAR !!! What does MyPyramid focus on concerning the grains group? Make half your grains whole. What recommendations do the Dietary Guidelines for Americans, make? What recommendations would the students provide to others?

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