Carbohydrates

Question 1

What are starches and their characteristics?

Answer 1

• Storage form of glucose in plants
• Especially rich in tubers or seeds
• Low in fruits, veggies
• Amylose -alpha 1-4 linkages
• Amylopectin - alpha 1-4 and 1-6linkages = branching

Question 2

What is glycogen and its characteristics?

Answer 2

• Stores glucose in animals; found in limited quantities in liver and muscles
• Average adult stores 340 g (or 1360 C)
• No dietary source of glycogen
• Upon harvesting, stores converted to lactic acid via anaerobic glucose metabolism
• Similar structure to amylopectin

Question 3

What is fiber and its characteristics?

Answer 3

• From plants structural components
• Cellulose - component of cell walls
• Similar to amylose, but hasBeta 1-4 linkages
• Greatest resistance to digestion compared to other dietary fiber molecules

Question 4

What foods or beverages contribute the most to the US population’s intake of added sugars?

Answer 4

• Sugar sweetened beverages, baked goods, ice cream, candy, cereal

Question 5

What is insoluble fiber?

Answer 5

• Comprised of cellulose, hemicellulose, and lignin
  • More abundant in US diet than soluble
  • Wheat bran
  • Lignin is not a polysaccharide

Question 6

What is soluble fiber?

Answer 6

- Suspended in solution
•	Absorbs water and cholesterol
•	Delays glucose absorption
•	Slows GI transit
•	Found in fruit, oats, barley, soy, and legumes
•	Examples: Pectin, gums, mucilage

Question 7

What are the health benefits of insoluble fiber?

Answer 7

• Adds bulk to stools
• Accelerates GI transit; preventing constipation
• Helps prevent diverticulosis, hemorrhoids, and appendicitis
• Decreases risk of colon cancer

Question 8

What are the health benefits of soluble fiber?

Answer 8

• Reduce risk of heart disease
• Hangs onto cholesterol dragging it out with fecal elimination
• Fermentation products capable of suppressing cholesterol synthesis
• Both actions lower overall blood cholesterol
• Delay glucose absorption
• Good choice for those with diabetes

Question 9

What are the current recommendations for fiber intake and the current DRI?

Answer 9

25-35 g/day

DRI = 14g/1000kcal

Question 10

What happens when you have too much fiber?

Answer 10

• Displace energy and nutrients from other foods
• Causes GI discomfort - bloating, gas, diarrhea
• Cation-exchange capacity - decrease absorption of trace minerals like iron and zinc

Question 11

What hormones are involved in glucose homeostasis?

Answer 11

Insulin and glucagon

Question 12

What does insulin do?

Answer 12

1. Released when blood glucose rises
2. Stimulates cells to take in glucose as glycogen stores or to convert to fate and stored
3. Both effectively lower blood glucose

Question 13

What does glucagon do?

Answer 13

1. Released from pancreas when blood glucose falls

2. Stimulates release of glucose from glycogen stores

Question 14

What does epinephrine do?

Answer 14

1. Adrenaline

2. Release glucose form stored glycogen for quick energy