Lecture 4- Carbs

Question 0

Function if carbs

Answer 0

• provide energy
• spare protein
• provide fiber
• provide sweetness

Question 1

Carbohydrates

Answer 1

• carbon
• oxygen
• hydrogen
• also called saccharides

Question 2

Simple carbs

Answer 2

• monosaccharide

- disaccharide: common form found in nature

Question 3

Complex carbs

Answer 3

• 3 or more monosaccharides
• oligosacchrides (3-10 monosaccharides)
• polysaccharide (hundreds of monosacharides)

Question 4

Monosaccharides

Answer 4

Glucose: must abundant sugar molecule in our diet; good energy source (not often found alone)
Fructose: sweetest natural sugar; found in fruit, high-fructose corn syrup
Galactose: does not occur alone in foods; binds with glucose to form lactose

Question 5

Galactose + glucose

Answer 5

Lactose

Question 6

Glucose + glucose

Answer 6

Maltose

Question 7

Glucose + fructose

Answer 7

Sucrose

Question 8

Polysaccharides

Answer 8

• Starch: storage forn of glucose in plants; food source include grains, legumes, amd tubers
• Glycogen: storage form of glucose in animals; stored in liver and muscles
• fiber: forms the support structure of leaves, stems, and plants

Question 10

Insoluble fiber

Answer 10

• does not dissolve in water
• part of plants cell wall
• not metabolized by bacteria
• contributes bulk to stool
• ex. Cellulose
• good source: whole grains

Question 11

Health benefits to insoluble fiber

Answer 11

• promote regular BM and decrease constipation
• help prevent hemorrhoids, diverticulitus
  • diverticula: bulging pockets in colon
• may lower the risk of colon cancer

Question 12

Soluble fiber

Answer 12

• dissolves in water, is viscous and gel- forming
• found in plant cells
• bacteria metabolize them easily
  Ex. Gums, pectin
• found in oatmeal, beans

Question 13

Health benefits to soluble fiber

Answer 13

Lowers cholesterol

Question 14

Total fiber and health benefits

Answer 14

• may improve blood glucose levels in diabetics
  • delay nutrient absorption and release of glucose into the blood stream
• high fiber diet may promote weight loss
  • food high in complex carbs= low in fat an sugar= lower calories
  • fiber an water= bulk, dense food
• delays gastric emptying
• increase satiety

Question 15

Whole grain

Answer 15

• Bran: fiber(insoluble) , vitamins
• Germ: vit E, healthy fats, protein, fiber, B vit
• endosperm: starch, small anounts of protein, minimal vits and min

Question 16

Grain Enriched

Answer 16

Add back nutrients that were lost in processing

• refined grains with riboflavin, niacin, thiamin, iron
• not with fiber, vit E, UFA, phytochemicals

Question 17

Grain fortified

Answer 17

Add ingredients that were not originally in the product

- folate, sterols, omega3 fatty acids, vit D in milk, extra iron

Question 18

What enzymes break down Carbs

Answer 18

Salivary and pancreatic amylase
- lactase, amylase
Brush border enzymes
- sucrose

Question 19

Absorptions of carbs

Answer 19

• monosaccharide: glucose, fructose, galactose are absorbed into the entrocyte
• enter capillaries and bloodstram —> liver
• in liver cells, fructose and glactose —> glucose

Question 20

The fate of glucose

Answer 20

• used for energy in liver and travelto other cells for energy production
• stored in liver and muscles as glycogen
• in consumed in excess of energy needs —> synthesize fatty acids
• used to maintain blood glucose levels to ensure adequate glucose for thr cells to make energy

Question 21

Carb metabolism

Answer 21

• glycolysis produces pyruvate
• pyruvate in the presence of O2 and with coenzymeA forms acetyl CoA
• acetyl CoA enters citric acid cycle
• these steps reduce coenzymes
• reduced coenzymes transport electrons to the ETC
• by product: ATP, water, CO2, oxidized coenzymes

Question 22

Oxidation

Answer 22

Loss of an electron

Question 23

Reduction

Answer 23

Gain if an electron

Question 24

Carbs in the body: stored as glycogen

Answer 24

If glucose is not needed for energy it is stored ad glycogen

• storage form of glucose
• used during sleep, fasting, excercise
• made and stored by liver and muscle tissues
• liver ~100g glycogen (400 Kcal) used to maintain BG to provide fuel for brain and RBC
• muscles: ~350g (1400 Kcal) used to meet muscle needs
  • is not released into the blood for use

Question 25

Excess carbs stored as fats

Answer 25

Lipogenesis: making fat from nonfat substances

• mostly occurs in liver cells
• travels to adipose cells for storage

Question 26

Blood glucose levels

Answer 26

-blood glucose: sugar in blood
- function of blood glucose is ti provide a circulating steady supply of fuel for cells
• immediately available so it can be taken up bu cells and used for energy
• peferred fuel for brain and only fuel for red blood cells
• used by muscles in aerobic excercise

Question 27

Pancreatic hormonrs that regulate blood glucose levels

Answer 27

• insulin

- glucagon

Question 28

Insulin

Answer 28

• cellular uptake of glucose (actuvr transport)
• uptake by liver and muscles to store as glycogen
• anabolic hormone
• secreted by pancreas

Question 29

Glucagon stimulates liver to…

Answer 29

• convert stored liver glycogen yo glucoose (glycogenesis)
• convert amino acids to glucose (gluconeogenesis)
• catabolic hormone
• secreted by pancreas

Question 30

Needs of carbs

Answer 30

• the RDA: 130g/day
• AMDR: 45-65% of energy
  • 2000 calories= 225-324 g
• AI for fiber:
  • 38g/d for 19-50 adult men
  • 25g/d for women
• AHA recommends:
  • 100 kcal-6 tsp for women
  • 150 kcal-9 tsp for men

Question 31

Diabetes

Answer 31

• inability to regulate blood glucose levels within the normal range
• if blood sugar level is less than 100mg that you are okay!
• if between 100-125 then considered prediabetes
• 126 and over, you have diabetes

Question 32

Type 1 diabetes

Answer 32

Autoimmune disease: own immune system destroys yhe insulin producing beta cells of pancreas

Question 33

Type 2 diabetes

Answer 33

Decrease sensitivity or response to insulin

Question 34

Symptoms and outcome of diabetes

Answer 34

Immediate symptoms

• frequent urination and unusual thirst: BG excreted in urine
• unusual weight loss -BG not entering cells, use pro/fat
• extreme hunger
• type 2: frequent infection and slow healing, blurred vision, numbness in hands and feet
• type 1: fruity odor breath, ketone production

Long term complications:

• damage to large blood vessels
• damage to small blood vessels (eyes: blindness, kidneys: kiney failure)
• amputation: nerve damage and increase blood glucose= microbial growth

Question 35

Diseases related to hypoglycemia

Answer 35

• low blood sugar (glucose) causing shakiness, sweating, anxiety
• reactive hypoglycemia: pancreas secretes too much insulin after a high- carb meal
• regualr small meals

Question 36

Glycemic index

Answer 36

• a food’s potential to raise blood glucose
• compared with standard amount of glucose or white bread
• increase glycemic index= rapid increase in blood glucose levels
• influenced by carb content, type of carb, the way it i prepared, fat and fiber content
• under 55 is low and over 77 is high
• glycemic load: GI x carbs in a typical portion
• possibly important for people with diabetes but total carb is important

Question 37

Polysaccharides: starch

Answer 37

Amylose: straight chain
Amylopectin: branched chain
- contain digestable alpha binds