This document provides an overview of a chapter 3 lecture on carbohydrates. It defines carbohydrates and discusses simple and complex carbohydrates. Complex carbohydrates include starch, fiber, and glycogen. The document outlines the digestion and absorption of carbohydrates and the role of insulin and glucagon in regulating blood glucose levels. It addresses recommendations for carbohydrate intake and sources of fiber-rich carbohydrates. The document also defines diabetes and describes types 1, 2, and prediabetes.

1. Chapter 3 Lecture
Chapter 3:
Carbohydrates
Plant-Derived
Energy Nutrients
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2. Learning Outcomes
1. Distinguish between simple and complex
carbohydrates.
2. List four functions of carbohydrates in our body.
3. Explain how carbohydrates are digested and
absorbed by our body.
4. Define the glycemic index and glycemic load.
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3. Learning Outcomes
5. Identify the RDA and the AMDR for
carbohydrates, and the AI for fiber.
6. Identify the most common dietary sources of
added sugars and the potential health risks of a
diet high in added sugars.
7. List five foods that are good sources of fiber-
rich carbohydrates.
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4. Learning Outcomes
8. Compare and contrast a variety of alternative
sweeteners.
9. Distinguish between type 1 diabetes, type 2
diabetes, and prediabetes.
10.Describe the lifestyle behaviors that can
prevent or control diabetes.
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5. What Are Carbohydrates?
• Carbohydrates
• One of the three macronutrients
• A primary energy source, especially for nerve
cells
• Molecules composed of carbon, hydrogen,
and oxygen atoms
• Most come from plant sources
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6. What Are Carbohydrates?
• Glucose
• The most abundant carbohydrate
• Produced by plants through photosynthesis
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7. Photosynthesis
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8. What Are Carbohydrates?
• Simple carbohydrates are sugars
• Contain one or two molecules
• Monosaccharides contain only one molecule.
• Glucose, fructose, galactose
• Disaccharides contain two molecules.
• Lactose, maltose, sucrose
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9. Constituent Parts of Simple Carbohydrates
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10. What Are Carbohydrates?
• Complex carbohydrates
• Long chains of glucose molecules
• Also called polysaccharides
• Starch, glycogen, and fiber
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11. Complex Carbohydrates
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12. Complex Carbohydrates
• Starch
• Plants store carbohydrates as starch.
• Humans digest (break down) starch into
glucose.
• Grains, legumes, and tubers are good
sources of starch in our diet.
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13. Complex Carbohydrates
• Fiber
• Fiber is the non-digestible part of plants.
• Dietary Fiber occurs naturally in foods.
• Found in whole grains, vegetables, seeds,
legumes, fruits
• Functional fiber is carbohydrate that is
manufactured and added to food.
• Cellulose, guar gum, pectin, psyllium
• Total fiber = dietary + functional fiber
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14. Complex Carbohydrates
• Soluble fiber
• Soluble in water and viscous (forms a gel
when wet)
• Found in citrus fruits, berries, oats and beans
• May reduce risk of cardiovascular disease
and Type 2 diabetes
• Insoluble fiber
• Insoluble in water
• Found in whole grains and vegetables
• Promote regular bowel movements
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15. Complex Carbohydrates
1. If you had to give nutrition advice to the general
public, what foods would you recommend for
increasing fiber intake?
2. Average fiber intake for Americans is much lower
than recommended levels. What are the reasons
Americans consume lower than recommended
amounts of fiber in their daily diet?
3. How might one's living environment, cultural
practices, socioeconomic status, and education
level limit their consumption of fiber rich foods?
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16. Complex Carbohydrates
• Glycogen
• Animals store carbohydrate as glycogen.
• Stored in the liver and muscles
• Broken down into glucose
• Rarely found in food and therefore not a
dietary source of carbohydrate
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17. Complex Carbohydrates
• What makes a whole grain whole?
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18. Whole Grains
1. How can we raise consumer awareness that there
is a discrepancy between the marketing of grain
products and the actual contents of grain products
for consumption?
2. How can companies be held to a better standard to
be more honest regarding the contents of
products?
3. Provide an argument for the need for the FDA to
define whole grains.
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19. Grains and Cereals Defined
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20. Why Do We Need to Eat Carbohydrates?
• Energy
• Each gram of carbohydrate = 4 kcal
• Important source of energy for all cells
• Critical energy source for brain cells and red
blood cells
• Glucose is especially important for energy
during exercise.
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21. Why Do We Need to Eat Carbohydrates?
• Energy
• Insufficient carbohydrate intake causes the
body to find an alternate source of glucose.
• Often proteins are broken down and used for
gluconeogenesis – the production of new
glucose.
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22. Why Do We Need to Eat Carbohydrates?
• Fiber-rich carbohydrates
• May reduce the risk of colon cancer
• May reduce the risk of heart disease
• May enhance weight loss
• May reduce risk of type 2 diabetes
• Help prevent hemorrhoids, constipation, and
diverticulosis
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23. Fiber-Rich Carbohydrates Have Health
Benefits
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24. Fiber-Rich Carbohydrates Have Health
Benefits
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25. Digestion of Carbohydrates
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26. What Happens to the Carbohydrates We
Eat?
• Salivary amylase
• Enzyme from saliva that begins carbohydrate
digestion in the mouth
• Breaks carbohydrates down into maltose
• There is little digestion of carbohydrates in the
stomach; most of this happens in the small
intestine.
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27. What Happens to the Carbohydrates We
Eat?
• Most chemical digestion of carbohydrates occurs
in the small intestine
• Pancreatic amylase
• Enzyme produced in the pancreas and
released into the small intestine
• Converts carbohydrates into maltose
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28. What Happens to the Carbohydrates We
Eat?
• Additional enzymes in the small intestine break
down any remaining disaccharides into
monosaccharides.
• These enzymes include maltase, sucrase, and
lactase.
• Monosaccharides are absorbed into the cells
lining the small intestine (enterocytes) and enter
the bloodstream.
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29. Lactose Intolerance
• Lactose intolerance
• Insufficient lactase production causes an
inability to completely digest the lactose
found in dairy products.
• Symptoms include intestinal gas, bloating,
nausea, cramping, diarrhea.
• Lactose-intolerant people may need to find
alternate sources of calcium.
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30. The Liver Converts All Sugars into Glucose
• Once absorbed into the bloodstream, all
monosaccharides are converted to glucose by
the liver.
• Glucose circulating in the blood is our primary
energy source.
• Excess glucose is converted to glycogen by the
liver.
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31. Absorption of Carbohydrates
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32. Digestion of Carbohydrates
• We do not have the enzymes necessary to
digest fiber.
• Bacteria in the large intestine can break down
some fiber.
• Most fiber remains undigested and is eliminated
with feces.
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33. Storage of Glycogen
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34. Digestion of Carbohydrates
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35. Regulation of Blood Glucose
• The level of glucose in the blood must be closely
regulated.
• Two hormones, insulin and glucagon, control
the level of glucose in the blood.
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36. Insulin
• Insulin
• Produced by beta cells of the pancreas
• Helps cells take in glucose from the blood
• Stimulates the liver to take up glucose and
convert it to glycogen
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37. High Blood Glucose
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38. Glucagon
• Glucagon
• Produced by alpha cells of the pancreas
• Stimulates the breakdown of glycogen to
glucose to make glucose available to cells of
the body
• Stimulates gluconeogenesis – the
production of new glucose from amino acids
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39. Low Blood Glucose
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40. Regulation of Blood Glucose
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41. Regulation of Blood Glucose
• Hypoglycemia
• Low blood-sugar (glucose) levels
• One cause is excessive insulin production
• Causes shakiness, sweating, anxiety,
weakness, irregular heart beat
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42. Effect of Food Upon Blood Glucose
• The glycemic index is a food's mathematical
potential to raise blood glucose levels.
• Glycemic load = amount of carbs x glycemic
index
• Foods with a low glycemic load:
• Cause low or moderate changes in blood
glucose
• Are better for people with diabetes
• May reduce the risk of heart disease and
colon cancer
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43. Glycemic Index Values for Selected Foods
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44. How Much Carbohydrate Should We Eat?
• Recommended Dietary Allowance (RDA) is 130
grams/day just to supply adequate glucose to
the brain
• A total of 45–65% of daily caloric intake should
be in the form of carbohydrates.
• Focus on fiber-rich and unprocessed
carbohydrates
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45. Simple Sugars
• Diets high in simple sugars:
• Can cause dental problems such as tooth
decay and gum disease
• May contribute to unhealthy levels of blood
lipid levels (cholesterol, etc.)
• Have not been proven to cause hyperactivity
• May contribute to obesity and diabetes
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46. Simple Sugars
1. What can you do to avoid overconsumption of
sugar?
2. Why is added sugar unhealthy? What diseases can
occur due to consuming high amounts of added
sugar?
3. What are some of the replacement
(counterconditioning) tactics that can help cut back
on our "want" of added sugar?
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47. Fiber-Rich Carbohydrates
• The Adequate Intake (AI) of fiber is:
• 25 grams/day for women
• 38 grams/day for men
• Most Americans eat only half the recommended
amount of fiber.
• Whole-grain foods are a more healthful choice
than foods with added sugar.
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48. Fiber-Rich Carbohydrates
• Excessive fiber can cause:
• Intestinal gas and bloating
• Dehydration if water is not increased
• Reduced absorption of certain nutrients
• Malnutrition if feeling "full" precludes intake of
other nutrients
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49. Fiber-Rich Carbohydrates
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50. Fiber-Rich Carbohydrates
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51. Alternative Sweeteners
• Nutritive
• Provide energy like simple carbohydrates
• Sugar alcohols
• Mannitol, sorbitol, xylitol, isomalt
• Decreased risk of dental caries
• 2–3 kcals/gm
• Can cause diarrhea
• Non-nutritive or alternative
• Provide little or no energy
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52. Alternative Sweeteners
• Acceptable Daily Intake (ADI)
• Saccharin
• Acesulfame-K
• Aspartame
• Sucralose
• Neotame
• Stevia
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53. To Exceed the ADI for Aspartame
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54. Carbohydrates in our Diet
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55. Carbohydrates in our Diet
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56. What is Diabetes?
• Diabetes
• Inability to regulate blood glucose levels
• Three types:
• Type 1 diabetes
• Type 2 diabetes
• Gestational diabetes
• Untreated diabetes can cause nerve damage,
kidney damage, blindness, the need for
amputations, and death.
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57. What is Diabetes?
1. Examine reasons more young adults are
developing type 2 diabetes now than in previous
generations.
2. Should the government take more stringent
guidelines to limit fast food restaurants from using
ingredients (such as high fructose corn syrup) or
offering large serving sizes that contribute to poor
nutritional health among consumers?
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58. Symptoms of Diabetes
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59. Forms of Diabetes
• Type 1 diabetes
• Accounts for 10% of all cases
• Patients do not produce enough insulin.
• Causes hyperglycemia – high blood sugar
(glucose)
• Requires insulin injections
• May be an autoimmune disease
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60. Forms of Diabetes
• Type 2 diabetes
• Most diabetics have type 2 diabetes.
• Body cells are resistant or less responsive to
insulin.
• Excess insulin is often produced.
• Causes hyperglycemia because cells cannot
take in the glucose from the blood
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61. Forms of Diabetes
• Pre-diabetes
• Impaired fasting glucose levels are higher
than normal but not high enough for a
diagnosis of type 2 diabetes
• Metabolic syndrome
• Waist circumference
• Blood pressure
• Blood lipids
• Blood glucose levels
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62. Forms of Diabetes
• Type 2 diabetes
• Cause is unclear, but genetics, obesity, and
physical inactivity play a role
• Treated with weight loss, diet, exercise, and
possibly oral medications and/or insulin
• Healthy lifestyle choices may prevent or delay
onset of type 2 diabetes.
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