Nutrition Chapter 5 Flashcards Preview

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Flashcards in Nutrition Chapter 5 Deck (43):
1

What are the 3 types of carbohydrate?

sugar, starch, fiber

2

What are the 4 forms of carbohydrate?

monosaccharide
disaccharide
oligosaccharide
polysaccharide

3

What are monosaccharides?

simple carbohydrate - one sugar, C6H12O6
galactose, glucose and fructose, sugar alcohols and pentoses (ribose, deoxyribose)
Foods - honey, fruits

4

What are the sugar alcohols?

xylitol, sorbitol, manitol

5

What are disaccharides?

simple carbohydrate, two sugars C12H24O12
maltose (2 glucose), sucrose (glucose and fructose), lactose (galactose and glucose)
Foods - table sugar, milk products

6

What are oligosaccharides?

complex carbohydrates, 3-10 sugar units
raffinose and stachyose
Foods - onions, beans, broccoli

7

What are polysaccharides?

complex carbohydrate, hundreds of sugars
starch and fiber

8

How is the digestibility of carbohydrates determined?

Whether they are linked by an alpha or beta bond. Alpha are easier to digest

9

What are starch and glycogen?

digestible polysaccharides
starch - storage form of glucose in plants
glycogen - storage form of glucose in animals

10

What are the 2 types of starch?

amylose and amylopectin
amylose - linear structure
amylopectin - high-branched structure
Foods - potatoes, beans, breads, pasta, rice

11

What is fiber?

indigestible polysaccharide
composed of cellulose, hemicelluose, pectins, gums and mucilages
can be soluble or insoluble
provides no appreciable energy
metabolized by colonic bacteria

12

What are sources of soluble fiber?

fruits, oats, barley, beans

13

What are sources of insoluble fiber?

whole grains, vegetables

14

How is fiber classified?

by its physical and chemical properties

15

What occurs during CHO digestion in the mouth?

salivary amylase breaks down starch
digestion is not appreciable

16

What occurs during CHO digestion in the stomach?

no digestion occurs in the stomach
HCl neutralizes the enzymes

17

What occurs during CHO digestion in the SI?

enzymes breakdown starch and disaccharides into monosaccharides
*intestinal cells release disaccharidases
*pancreatic amylase

18

What role does the pancreas play in CHO digestion?

releases sodium bicarbonate to neutralize acid and allow digestion to occur
releases enzymes

19

How are the monosaccharides absorbed?

via facilitated or active absorption

20

What occurs when monosaccharides are absorbed?

They are transported to the liver and converted to glucose for energy or stored as glycogen.

21

How is fiber digested?

mouth - mechanical actions break it down
stomach - no digestion, but it delays gastric emptying
SI - no digestion, delays absorption of nutrients
LI - bacteria enzymes digest fiber, covert to fatty acids or gas

22

What functions does fiber have in the LI?

holds water, regulates bowel activity, binds to bile, cholesterol and some minerals and carries them out of the body, enhances health of large intestinal cells

23

How does fiber effect cholesterol?

enterohepatic circulation

24

What is the recommended dietary fiber intake?

AI for women 25g
AI for men 38g
DV = 25g

25

How much fiber does the average American intake?

13-17g

26

What are problems of excessive fiber intake (chronic)?

need extra fluid
binds to some minerals
develop phytobezoars
fill the stomach of a young child quickly

27

Carbohydrate Metabolism

energy - ATP from TCA cycle, ETC, glycolysis
stored - fat or glycogen

28

What are problems with lack of dietary carbohydrate?

glycogenolysis (glucose released from glycogen stores)
gluconeogenesis (protein used as source of glucose)
ketosis (incomplete metabolism of fats leads to ketone production)

29

What are the functions of carbohydrates?

provide energy
spare protein
prevent ketosis

30

How is glucose regulated (homeostasis)?

major organs: pancreas and liver
major hormones: insulin and glucagon
other hormones: epinephrine/norepinephrine, cortisol, growth hormone

31

What happens if glucose homeostasis isn't achieved?

hyperglycemia (diabetes)
hypoglycemia

32

What is insulin? What are its functions?

hormone released by the pancreas in response to high blood glucose
increases glucose uptake by the cells, promotes glycogen synthesis, reduces gluconeogenesis
net effect: lower blood glucose

33

What is glucagon? What are its functions?

hormone released by the pancreas in response to low blood glucose
breaks down glycogen, enhances gluconeogenesis
net effect: raises blood glucose

34

What is the function of epinephrine and norepinephrine?

raises blood glucose
fight or flight response
breaks down glycogen

35

What is the function of cortisol and growth hormone?

raises blood glucose
increases gluconeogenesis

36

What is the glycemic response?

refers to how quickly and how high blood glucose levels rise after eating and how quickly the return to normal

37

What is the glycemic index?

blood glucose response of a given food compared to a reference food

38

What is the glycemic load?

amount of CHO in a food x the GI

39

What is the effect of a high glycemic load?

increases insulin output, insulin increases triglycerides, small LDL and fat synthesis
reduces satiety, muscles may become insulin resistant

40

What is the recommended CHO intake?

45-65% of calories
RDA is 130g
need 50-100g to prevent ketosis
current intake is about 50% of kcal

41

What is the recommend intake of added sugars?

DGA = less than 6% of kcal
WHO = less than 10% of kcal

42

What are the effects of a high sugar diet?

dental caries
high glycemic index
indirectly related to dev. of diabetes
nutrient deficiencies (low nutrient density, empty and excess kcal, soda replacing milk)

43

What are the effects of starch and fiber?

reduces the risk of certain diseases
CVD, diabetes, obesity, some cancers, diverticular disease