Chapter 4 - Carbohydrates Flashcards
simple carbohydrates
monosaccharides
disaccharides
- perceived as sweeter than complex carbs
monosaccharides
- single sugars
- include:
glucose - blood sugar, essential energy source for body
fructose - sweetest sugar, fruits, honey
galactose - part of lactose
glucose
- most abundant monosaccharide in body
- preferred energy source for brain & red blood cells
disaccharides
- made of 2 monosaccharides
- glucose is always 1
- include:
maltose - 2 glucose
sucrose - fructose & glucose
lactose - galactose & glucose
polysaccharides
- many sugars linked together
- include:
glycogen
starches
fibers
glycogen
- polysaccharide
- only found in meats & not in plants, so body makes it
- stores glucose for future use
- stored in liver and muscle cells
starches
- polysaccharide
- plants store glucose as starches
- all starch comes from plants (beans, tubers, grains)
- amylose & amylopectin
fibers
- polysaccharide (nonstarch)
- pass through the body undigested, so contribute little or no energy
- soluble & insoluble
difference between fibers & starches
bonds between the monosaccharides in fibers cannot be broken down by digestive enzymes in the body
insoluble fibers
- do not dissolve in water, form gels or ferment
- found mostly in whole grains and veggies
- promote bowel movements, alleviate constipation, & prevent diverticular disease
- cellulose
- inulin
soluble fibers
- dissolve in water
- easily digested by bacteria in colon
- pectins
- gums
- mucilages (viscous)
- resistant starch
condensation
two monosaccharides can be linked together through this reaction to form a disaccharide & water
hydrolysis
a dissacharide can be broken into its two monosaccharides by this reaction using water
amylase
- from salivary glands
- starts the breakdown of amylose (a forms of starch)
amylose
- polysaccharide / straight chain
- more resistant to digestion
- may improve health of digestive tract; improve glucose tolerance; stimulate growth of beneficial intestinal bacteria
amylopectin
- polysaccharide / branched chain
- easier to digest
fiber health benefits
Soluble fibers
- slow gastric emptying & may delay absorption of some nutrients
- improve appetite control
- normalize blood glucose levels
- may help protect against colon cancer
Insoluble fibers - relieve constipation
oligosaccharides
- similar in length to simple carbs
- similar in makeup to polysaccharides
- humans lack enzyme to digest them
- intestinal microflora digest & ferment them (cause bloating & flatulence)
- food sources - legumes, beans, cabbage broccoli
how are carbohydrates absorbed?
glucose & galactose - active transport
fructose - facilitated diffusion
lactase deficiency
a lack of the enzyme needed to digest the disaccharide lactose into its monosaccharides (glucose & galactose)
kefir
a fermented milk created by adding lactobacillicus acidophilus & other bacteria that break down lactose to galactose and glucose, producing a sweet, lactose-free product
gluconeogenesis
the making of glucose from a non carbohydrate source
protein-sparing action
the action of carbohydrate (and fat) in providing energy that allows protein to be used for other purposes
What does liver do with glucose?
- assembles small glucose units into glycogen for storage
2. stores extra glucose as fat for export to other cells
What happens to glucose in the blood?
- muscles cells convert to glycogen
- liver stores as glycogen & fat
- most cells take what they need for energy right away
What are the glucose regulating hormones?
- insulin
- glucagon
- epinephrine - under stress, acts quickly to ensure that all body cells have energy fuel in emergencies
normal blood glucose (fasting)
70 - 100 mg/dL
diabetes mellitus
- refers to diabetes that is caused by high levels of glucose in the blood
- Type 1 & type 2
Type 1 diabetes
body does not produce insulin
Type 2 diabetes
body’s insulin receptors become insensitive, so no longer respond to insulin
hypoglycemia
- abnormally low blood glucose concentration
- symptoms include: sweating, anxiety, hunger, & trembline
glycemic response
the extent to which a food raises the blood glucose concentration & elicits an insulin response
how do added sugars contribute to health problems?
- dental caries (cavities)
- contribute to nutrient deficiencies by nudging out nutrients
- too much contributes to weight gain & obesity
What are the carbohydrate-rich foods?
whole grains vegetables legumes fruits nuts
health benefits of fiber-rich carbohydrates?
- benefit heart - can lower blood cholesterol, lower blood pressure
- diabetes - soluble fibers trap nutrients & delay trasport thru GI tract, which slows glucose absorption (helps prevent glucose surge & rebound)
- GI health - reduces constipation; increases health of large intestine
- Cancer - high fiber protests against colon cancer
- Weight management - tend to be low in fat & added sugars; contribute to feeling full
Acceptable Macronutrient Distribution Ranges (AMDR)
Carbs: 45-65%
Fat: 20-35%
Protein: 10-35%
