1. Carbohydrates

2. Learning Outcomes
Identify the major types of carbohydrates and give examples of food sources for each
List alternative sweeteners that can be used to reduce sugar intake
Describe recommendations for carbohydrate intake and health risks caused by low or excessive intakes
List the functions of carbohydrates in the body

3. Learning Outcomes Explain how carbohydrates are digested and absorbed
Explain the cause of, effects of and dietary treatment for lactose intolerance
Describe the regulation of blood glucose, conditions caused by blood glucose imbalance, types of diabetes, and dietary treatment for diabetes
Describe dietary measures to reduce the risk of developing type 2 diabetes

4. Carbohydrates Composed of carbon, hydrogen and oxygen
Produced by plants via photosynthesis
Simple carbohydrates
Monosaccharides and Disaccharides
Polysaccharides (more complex)
Starch, Glycogen, and Fiber

6. Monosaccharides Glucose Fructose Galactose
Blood sugar
Fructose
High-fructose corn syrup
Galactose
Part of lactose
Sugar Alcohols (monosaccharide derivatives)
Xylitol, mannitol and sorbitol
Pentoses (5 carbon)
Ribose and Deoxyribose

8. Disaccharides Two monosaccharides linked by a condensation reaction
Alpha or beta C-O-C bonds connect them
Maltose
Glucose and Glucose; alpha bond
Sucrose
Glucose and Fructose; alpha bond
Lactose
Galactose and Glucose; beta bond

9. Complex Carbohydrates
Oligosaccharides
Contain 3-10 sugar units
Raffinose and Stachyose
Indigestible; bacterial fermentation – gas
Polysaccharides
Contain many glucose molecules
Alpha or beta bond determine digestibility

10. Digestible Polysaccharides
Starch (plants)
Amylose: straight chain
Amylopectin: branched
Glycogen (animals)
Storage form of glucose in human body
Liver glycogen (90g): converted to blood sugar
Muscle glycogen (300g): glucose for muscle use

12. Indigestible Polysaccharides
Total Fiber
Dietary Fiber + Functional Fiber
Soluble Fibers
Pectin, gum, mucilages and some hemicelluloses
Insoluble Fibers
Cellulose, hemicelluloses and lignin
Health benefits of fibers

14. Carbohydrates in Foods
Starch
Fiber
Nutritive Sweeteners
Mono and disaccharides
High fructose corn syrup
Sugar alcohols

16. Alternative (Non-Nutritive) Sweeteners
Yield no energy
Acceptable Daily Intake (ADI)
Saccharin
Oldest alternative sweetener,
Develops bitter taste with cooking
Aspartame
Cannot be used in cooking
Contains phenyalanine

17. Alternative Sweeteners
Neotame
Similar to aspartame but not digested
Acesulfamine K
Can be used in cooking
Sucralose
Made from sucrose-can be used in cooking
Tagatose
Isomer of fructose, pre-biotic
Stevia
Recently approved by FDA for use in beverages
Sold as dietary supplement

18. Recommended Intake of Carbohydrates
RDA-130 grams
45%-65% of total energy needs
Limit added sugars and caloric sweeteners
Fiber: 14g/1000kcal is adequate intake
25g/d - women under 50 (21g/d after 51)
38g/d - men under 50 (30g/d after 51)

19. Our Carbohydrate Intake
50% of total energy needs
Added sugars 16% of kcal
Recommendations:
6% of kcal (Dietary Guidelines)
10% of kcal (WHO)
25% of kcal (DRIs)
Dietary fiber
25-50% less than recommended
Average intake-1 fruit and 1 or fewer whole grain servings

20. Functions of Digestible Carbohydrates in the Body
Provide energy: 4 kcal/g
Spare protein
Body does not utilize gluconeogenesis
Prevent ketosis
Incomplete breakdown of fatty acids

21. Functions of Indigestible Carbohydrates in the Body
Promoting bowel health
Constipation and hemorrhoids
Diverticulosis and diverticulitis
Reducing obesity risk
Fullness and satiety
Enhancing blood glucose control
soluble fibers
Reducing cholesterol absorption

23. Carbohydrate Digestion
Mouth
Salivary amylase begins digestion
Small intestine
Specific enzymes break down disaccharides
Maltase: maltose; sucrase: sucrose; lactase:lactose
Fiber not broken down

24. Carbohydrate Absorption
Active absorption: Glucose and Galactose
Facilitated absorption: Fructose
Liver converts fructose and galactose to glucose
Blood glucose used by cells
Glucose storage: muscle and liver glycogen
Excess glucose: converted to fat by liver (stored in adipose tissue)

26. Health Concerns Related to Carbohydrate
Very High Fiber Diets (above grams)
High fiber + low fluid = constipation, hemorrhoids, blockage
Decrease absorption of certain minerals
High Sugar Diets
Increase risk of weight gain and obesity
Increase risk of dental caries
Cardiovascular disease?

27. Health Concerns Related to Carbohydrate
Lactose Intolerance
Primary
Decreased lactase production
Secondary
Associated with disease that damage the lactase- producing cells
Glucose Intolerance
Hypoglycemia
Hyperglycemia

28. Regulation of Blood Glucose
Normal concentration: mg/dL
Regulated by liver
Insulin (pancreas)
Hormone that facilitates transfer of glucose from blood into cells
Lowers blood glucose
Glucagon, Cortisol, Epinephrine, Norepinephrine and Growth Hormone
Raise blood glucose

30. Other Blood Sugar Disorders
Metabolic Syndrome
Group of factors that increase risk for Type 2 diabetes and cardiovascular disease
Hypoglycemia
Reactive Hypoglycemia
Exaggerated insulin response after eating
Fasting Hypoglycemia
Low blood sugar after fasting

31. Glycemic Index and Glycemic Load
Glycemic Index (GI)
Ratio of the blood glucose response to a given food, compared with a standard
Influenced by many factors
Based on a 50g carbohydrate serving
Glycemic Load
Amount of carbohydrate in consumed food multiplied by GI and divided by 100
Better reflects a food’s effect on blood glucose than GI alone

32. Medical Perspective
Diabetes Mellitus

33. Type 1 Diabetes Mellitus
Insulin producing cells in pancreas are destroyed (autoimmune disease)
Insulin therapy required for life
Diet must be coordinated with insulin
Exchange system, carbohydrate counting
Increased risk for cardiovascular disease, blindness and kidney disease

34. Type 2 Diabetes Mellitus
Progressive disease
Characterized by insulin resistance
Insulin production may be low, normal, or high
Most common type of diabetes (90% of cases)
Treatment:
Diet
Physical activity
Medications