Nutrition Chp 3
Terms
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- II. Why we need carbs
- for energy
- III. Simple carbs
- sugars, available carbs
- 1. Monosaccharide
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a. Different sweetness
b. Provide E
c. Have general CnH2nOn
d. ready to go quickly absorbed - i. Glucose
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1. monosacc
2. Essential E source
3. One of 2 sugars in disaccharides
blood sugar⬝ or dextrose - ii. Fructose
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fruit sugar⬝ or levulose
1. monosacc
2. sweetest
3. same form, glucose diff structure
4. honey, cereal, fruits, soft drinks - iii. galactose
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1. monosacc
2. part of disaccharide lactose
3. rarely occurs by itself - 2. Disaccharide
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a. Pairs of monosaccs linked together
b. Condensationes
c. Hydrolysis ÷es --- occurs in digestion
d. Glucose + monsacc
e. Derives from plants except lactose - i. Maltose
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malt sugarâ€
2. has 2 glucose units – alcohol
3. whenever starch breaks ↓
a. carb digestion
disacc - ii. sucrose
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1. glucose + fructose
2. fruits, veggies, grain
3. sugars (powdered, white, brown)
disacc - iii. lactose
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1. galactose + glucose
2. main part of milk
3. “milk sugarâ€
diacc - Complex Carbohydrates
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1. starches and fibers
2. polysaccharides - 2. polysaccharides
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a. ed of straight/branches monosaccs
b. Several monosaccs linked together
Glycogen, starches, fibers - i. Glycogen
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1. many glucoses linked together as highly branched chains fast hydrolysis
2. stored in liver and muscles as a form of glucose
3. not sig food source of carbs
4. not complex carbs in food
5. storage form of glucose ing E for humans
6. found limitedly in meat, some plants
polysacc - ii. starches
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1. plant polysaccs composed of glucose
2. storage form of glucose ïƒ E for humans
3. available carb (simple carb)
4. most of glucose supply
5. all starchy foods come from plants, beans, grains, wheat/rice
6. Amylopectin – a component of starch, other is glucose - iii. fibers
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1. most are polysaccs
2. no contain monosaccs no E
3. soluble fibers and insoluble fibers - 3. soluble fibers
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dissolve in water, ex pectin (thicken jelly)
a. viscous – gel like
b. fermentable – degree
that bacteria can break ↓
fibers to frags
c. fruits, oatmeal, barley, legumes
d. sponge - absorbs
e. decreases cholesterol, 5-10 g/day - 4. insoluble fibers
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a. nonviscous, less fermented
b. whole grains, veggies
c. ↑ bowel movements, increases motility, makes food LEAVE
d. don't dissolve in H20 - characs of fibers
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5. from plants
6. veggies, fruits, grains, beans
7. each has diff struct - structures of fiber
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a. cellulose
b. Hemicelluloses
c. Pectins
e. Mucilages
f. Lignin
g. Resistant starches - fibers from plants
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a. nonstarch polysaccs --- not digested by humans
b. unavailable carbs b/c can’t break ↓
c. cant be broken ↓ by digestive enzymes like starches - a. cellulose
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i. plant cell walls
ii. ïƒ no broken ↓ humans - b. Hemicelluloses
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i. Main pt cereal fibers
ii. Made up monosaccs and branching monosaccs - c. Pectins
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i. Backbone of one type of monsacc
ii. Veggies and fruits (citrus)
iii. Thicken jelly, keep salad dressing ÷ing - d. Gums
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i. Plant secretion
ii. Addititives to thicken foods - e. Mucilages
- i. +ed to foods as stabilizers
- f. Lignin
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i. Nonpolysacc
ii. 3-d structure strength
iii. Woody taste in veggies - g. Resistant starches
- i. Escape digestion/absorption
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How carbs are digested
in mouth -
1. in mouth – saliva, chewing, amylase,
a. amylase – enzyme that hydrolyzes amylose, breaks ↓ carbs
i. amylose – form of starch
ii. hydrolyzes starch to maltose
iii. very little digestion -
how carbs digested
in stomach -
bolus, stomach acid and protein digesting enzymes -> stop amylase and salivary enzymes
a. ->es satiety
b. hydrochloric acid churns food -
how carbs digested
in small intestine -
most of work of carb digestion, pancreatic amylase (breaks ↓ polysaccs to disaccs), enzymes take apart specific disaccs
a. maltase ïƒ two glucoses
b. sucrase ïƒ one glucose + one fructose
c. lactase ïƒ one gluclose + one galactose
d. now, all polysaccs/disacs are monosaccs -
how carbs digested
in large intestine -
1-4 hours, all sugs/starches digested,
a. fibers only ones left
i. attract H20 soft poo - carb absorption
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in SI,
monosaccs enter capillaries of intestinal villi --- monosaccs travel to liver thru portal vein
3. galactose and fructose ed into glucose - carb metabolism
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1.store glucose as glycogen
a.liver stores 1/3 of body’s total glycogen
b.after meal, blood glucose ↑es
i. condensation →ing long branches glycogen
c.blood glucose ↓es
i.liver cells hydrolysis
ii.single molecules, bloodstream
d.glucose supplies E to other areas regardless of recent meal
e.muscles stores glycogen (other 2/3s)
I. use in exercise - 2. using glucose for E
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a. fuel, breaks in ½
b. can us eother nutrients, fat & ptein but not as easy
c. liver only uses for a few hours - 3. making glucose from Protein
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a. protein has other jobs and fat = no
b. gluconeogenesis – making glucose from noncarb source ïƒ don’t want this
c. protein sparing action –carb/fat ïƒ ing E, allows ptein used real purpose
d. need 50-100 g carbs/day
e. 45-65% - 4. making ketone bodies from fat frags
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a. when lack carbs, ketone bodies form incomplete break ↓ of fat, when excess ïƒ
i. ketosis
1. ↑ level of ketone, disturbs pH balance - 5. how many carbs do you need?
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a. 45-65%
b. 225-325 g --- 900-1300 cal
c. RDA 130 g
d. DV 300 g
e. Calculate total - Lactose Intolerance
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i. Inability to digest milk sugar lactose
ii. Different than milk allergy - VIII. Maintaining Blood Glucose
- homeostasis
- regulators of blood glucose
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insulin
glucagon
epinephrine - a. insulin
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hormone, released in response to ↑ levels blood glucose
i. purpose: remove glucose from blood into muscle/fat cells
allows cells to absorb blood glucose and store as glycogen in liver
regulates blood glucose - b. glucagon
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i. when blood glucose ↓es (b/t meals), pancreas ïƒ es glucagon
ii. ïƒ es ↑ blood glucose, signals liver to release glucose storage - a. Epinephrine
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fight or flight⬝ hormone, acts quickly, adrenaline
regulator of blood glucose - 4. diabetes
- a. disorder of carb metab, inad/ineffect insulin
- i. type 1 diabetes
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1. less common
2. pancreas fails insulin, unknown cause - ii. type 2 diabetes
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1. more common
2. cells don’t respond insulin
3. effect of obesity
4. prevent how? Healthy body weight - 5. hypoglycemia
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a. blood glucose ↓es dramatically ïƒ es mini attack
b. effect of poorly controlled diabetes
c. rare in healthy ppl - 6. glycemic index
- a. way of classifying foods to potential to ↑ blood glucose
- a. Nutritive sweeteners
- – sweeteners that ïƒ E, includes sugars/sugar replacers
- b. Hyperactivity
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has been disproven, sugar no link to ADD/ADHD
i. Inattentive/impulsive behavior ↑ freq than age bracket - c. Recommendation sugar
- i. No upper limit, no > 25%
- d. Health threat sugar
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i. Dental caries
ii. Might displace other nutrient needs
iii. Natural sugars ok: veggies, fruits - V. Effects of Fibers
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a. Weight manage, ↓ blood cholest,
b. Prevents
i. Colon cancer, diabetes, homerrhoids, appendicitis, diverticulosis - c. Excessive amts fiber
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i. Displaces E and nut-dense foods
ii. →es intestinal probs
iii. Interfere w/ mineral absorp - d. How much fiber we need?
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i. 23-30 g
ii.