Exam 1: Carbohydrates Flashcards
Macronutrients that provide energy (Calories)
Carbs, Lipids, and Proteins
Acceptable macronutrient distribution range (AMDR) for Carbohydrates
45-65% Cal
AMDR for total fat
20-35% Cal
AMDR for protein
10-35% Cal
RDA for carbohydrates
130 g
25 for women, 38 for men
RDA for Omega 6
11-17 g
RDA for Omega 3
1.1-1.6 g
RDA for Protein
0.8 g/kg body weight
Carbohydrates are found in ____
Plants (starches and sugars)
Major source of energy in the diet
carbs
Carbs provide ____Cal/g
4 Cal/g
Categories of carbs
Monosaccharides
Disaccharides and Oligosaccharides
Polysaccharides
Glucose, Fructose, Galactose are
monosaccharides (simple)
Sucrose, Lactose, Maltose
Disaccharides (simple)
Starch, glycogen, fiber
Polysaccharides (complex)
Glucose is known as ___ and required by ____-
blood sugar, required by brain
Fructose is the ______ of all monosaccharides and is found in _____
sweetest, found in fruits and honey
Galactose is produced by ___________ and if you are unable to metabolize galactose its called _____
produced by digestion of lactose into glucose and galactose. Inability to metabolize galactose= galactosemia
*epimer of glucose
Disaccharides are bound by ____ and digested by ____
glycosidic bonds, digested by brush border enzymes (sucrase, lactase, maltase, etc.)
Sucrose is the only
nonreducing sugar (glucose (alpha1-beta2) fructose
Sucrose is an
invert sugar (free glucose and fructose in 1:1 ratio, much sweeter than sucrose)
The natural inver sugar is
honey
Maltose
Glucose alpha (1-4) glucose product of starch degradation
Lactose
- Galactose beta(1-4) glucose
- Made in mammary glands of lactating mammals ( major sugar in breast milk)
- Lack of lactase is most common form of carbohydrate malabsorption (found in 25% of adults)
Lactose _____ with aging of cheese
decreases
We don’t digest
oligosaccharides
Oligosaccharides are ___ sugars long, water ____, sweet, and act as ___
3-10 sugars, water soluble, act as fibers (good prebiotics)
Polysaccharides have ____ sugars
10 or more
Starch is the storage form of carbs in
plants
glycogen is the storage form of carbs in
mammals
Fiber is
non digestible plant material
Starch is 100% ___ and a combo of ___ and _____
glucose, amylose and amylopectin
Starch is found in
corn, rice, potato, arrowroot, tapioca
- usually has more pectin %
Resistant starch
recrystallizes after cooking to resist digestion; usually fermented
RS1 is ______ for digestion
inaccessible, goes to large intestine and may get fermented
RS2 has a certain ________ that is _____ to digestion
compact granular form, resistant to digestion
RS3 is the _____ resistant, and able to be ______ from cooling gelatinized starch
most resistant, retrograded from cooling
RS4 is
chemically synthesized
AKA Modified starches
3 components of a whole grain
endosperm= starch germ= oil bran= insoluble fiber
Examples of whole grains
buckwheat, bulgur, corn, millet, brown rice, rye, oats, sorghum, wheat and wild rice
Plant sterols in whole grains
decrease cholesterol absorption
Vitamins/ minerals found in whole grains
vitamin E, selenium, zinc
Lignan in whole grains
plant estrogen (protective against breast cancer)
Antioxidants in whole grains
decrease oxidation
Phytate in whole grains
antinutrient- can bind minerals
Whole grain insoluble fiber ___________ and resistant starches act like _____
speeds up GI transit, acts like soluble fiber
Soluble fiber in whole grains
increase satiety; binds cholesterol, TAG and glucose and decreases cholesterol absorption
Whole grain recommendation
48 g of whole grains/day
Average Americans eat about 16g/day
a food IS whole grain if the ingredient list says
- Whole grain (name of grain)
- Brown Rice
- Oats, oatmeal
- wheat berries
- **Maybe multigrain organic flour and semolina
A food is NOT whole grain if the ingredient list says:
- Enriched flour
- Degerminated (on corn meal)
- Bran
- Wheat germ
Glycogen is only found in
meat (tiny amounts), 100% glucose that is more highly branched than amylopectin
Glycogen is the storage form of carbs in
mammals
Liver regulates ____, _____% of glycogen is used after 1 hour of aerobic activity and it is completely depleted after _____
blood glucose, 50%, depleted after 15 hours
Glycogen is used in muscle for _____ but cannot be released from the muscle once _______. The amount can _____ in trained muscle
exercise, phosphorylated, double in trained muscle
The liver normally has ___g of glycogen
100g (400 kcal when full)
The muscles usually hold ___ g of glycogen in untrained sedentary individuals
350g (1400 kcal)
Soluble fibers
Beta-glucans Gums Wheat dextrin Psyllium Pectin Inulin (fructans) Konjac Glucomannan
Insoluble fibers
Cellulose
Lignin
Most hemicelluloses
Viscous fibers are binders
Pectin Beta Glucans Some gums Psyllium Konjac Glucomannan
Fermentable fibers cause gas and are SCFA
Pectin Beta-glucans Guar gum Inulin Wheat dextrin
Non-fermentable fibers increase motility
cellulose
lignin
Fiber contain in beans
7-9 g/ 1/2 cup, cooked
Fiber content of Nuts and seeds
2-5 g per ounce
Fruits, breads, and cereals fiber content
1-3 g/serving (Bran cereal can contain up to 14 g/serving)
Veggies can contain up to
3-5 g per 1/2, cooked
Insoluble Fiber in the GI tract
increases water-holding capacity, fecal volume and decreases GI transit time (speeds up)
Soluble fibers in the GI tract
- increase GI transit time, form gels, binds nutrients
- decreases absorption (cholesterol and minerals)
Kids and elderly who eat too much high fiber foods will fill up too fast and can become
malnourished
Nutritive sweeteners
sweet compound that provides some energy
“sugar alcohols” provide 2-3 kcal/g
Examples of nutritive sweeteners
sorbitol, mannitol, xylitol
Nonnutritive sweetener
sweet compound that doesn’t provide energy (artificial sweeteners)
Examples of nonnutritive sweeteners
aspartame, monk fruit, stevia
Functions of carbs
- Fuel supply
- Reserve fuel supply (in liver and muscle)
- Special tissue function (CNS)
Low glucose can result in
coma and death because the CNS can’t survive on ketones alone
The Kidney excretes ____ glucose/ day
> 200 mg/microliter
Natural sugars
found as part of food in nature (lactose in milk, glucose and fructose in fruit, honey, etc.)
Added sugars
natural sugars NOT found naturally in that particular food (high fructose corn syrup or sucrose in soda)
WHO, FAO, and DGA suggest ________ of our total energy comes from added sugars
<10%
Foods with added sugars often displace _______ and is a major cause of ____________ in the U.S.
nutrient-rich foods, nutritional deficiency with over nutrition
What affects blood glucose and increases triglycerides ?
sugars and starch
Glycemic Index (GI) is
ranking system used to compare how foods will increase blood sugar (scale of 100)
Low GI
<56
- oatmeal, most fruits, sweet potatoes, legumes, lentils, chocolate
Moderate GI
56-69
- quick oats
- brown or wild rice
High GI
70+
- pretzels, short grain white rice, mac and cheese, cereals
Glycemic Load (GL)
takes into account how much fiber is in the product and how it impacts blood sugar (better than GI)
Apple GI=_____ and Glycemic Load=____-
40, 6
Net carbs are ____ by the FDA and encourages the use of _______
not regulated, sugar alcohols
- provide some calories and can greatly increase blood sugar
Sugar alcohols are
laxatives
Hypertriglyceridemia is often a result of
high carb diets (often high carbs, not high lipids)
What uses most of the 200g of glucose needed per day?
brain
When blood sugar falls below 40 mg/dL, what happens?
fat burning increases
When blood sugar is about 180 mg/dL what happens?
glucose spills into urine
Carbs stimulate
insulin release
Insulin facilitates _____ uptake and stimulates _____ in the liver
glucose, lipid synthesis
Triglycerides are packed into ____ and sent into the blood
VLDL, then they turn into LDL
Carb digestion in the mouth
salivary alpha-amylase
Carb digestion in stomach
NONE
carb digestion in the pancreas
pancreatic alpha-amylase
carb digestion in the small intestine
Lactase, sucrase, maltase, isomaltase
Monosaccharides are absorbed by ______ or ______
active transport or facilitated diffusion
Dietary fiber AI for adults >50 years
Men= 30 g/day Women= 21 g/day
Dietary fiber AI for adults (18-50) years
Men= 38 g/day Women= 25 g/day
The average American consumes _______ of dietary fiber
12-18 g/day
Total carb RDA for adults
130 g/day
Total carb AMDR
45-65% Cal
Dietary guidelines for carbs
- Consume at least half of grains as whole
- Increase veggie and whole fruit intake
- Choose nutrient-dense foods
- Reduce added sugars to <10% of Cal
