week3 carbs Flashcards
function of carbs
-energy, especially blood cells, brain and nervous system
- protein sparing –enough CHO ensures protein can be used for growth and development
fat metabolism - CHO needed to fully metabolize fats
monosaccharide
saccharide = sugar
glucose
galactose
fructose
GI tract function
components of body compounds
disaccharide
disaccharide combination of 2 monosaccharide
maltose
sucrose
lactose
joined via condensation = H2O
broken via hydrolysis (need H2O)
oligosaccharides
oligo= few 3-10 carbon
not digested well produce gas
found in beans
Polysaccharides
Poly = many
Make starch, glycogen, and cellulose
Complex CHO
Mono and di = simple
Starch = storage form CHO in plants
Glycogen = storage form of CHO in animals
Fiber = provide structure in plants
cellulose = fiber
- non digestible part of a plant cell wall
- phytic acid is often found with fiber, binds to minerals so they cant be absorbed
lactose intolerance
inability to digest lactose well
- insufficient lactase to break down lactose
-Lactase is highest at birth, and declines afterwards
-Only 30% of the population retain enough lactase to
fully digest and absorb lactose
-Exists on a continuum from mild to severe
-Caused by disease, meds, diarrhea, malnutrition
-Can be temporary or permanent
-Lactose remains undigested, attracting water and acting as food for intestinal bacteria
-Causes gas, bloating, diarrhea, cramps
lactose intolerance management tips
- total elimination not necessary, may be harmful
if you are lactose what can you eat to recover your lactase population?
fermented dairy products
if you dont have enough lactase
-Lactose remains undigested, attracting water and acting as food for intestinal bacteria
-Causes gas, bloating, diarrhea, cramps
lactose intolerance management tips
-Total elimination not necessary, may be
harmful
-A change in type, #, activity of GI bacteria accounts for ability to adapt to lactose
-Spread out intake over the day
-Combine dairy with other foods
-Have dairy foods with less lactose yogurt, hard cheeses
-Use lactose free products, lactaid pills
Fermented dairy
*lactose intolerance is NOT an allergy
mouth digestion
salivary enzyme amylase hydrolyze starch to shorter polysaccharides and disaccharides
stomach
stomach does not contain any enzyme to breakdown CHO, so CHO digestion cease here
small intestine
Most of the work, pancreatic amylase breaks CHO down to
disaccharides, maltase/sucrase/lactase breaks down to
monosaccharides
larger intestine
Nondigestible CHO remain here = fibers. They attract water to soften
stool, and bacteria ferment other fibers, generating gas, water, fats.
Resistant starch escape digestion/absorption
carbohydrate absorption
- some glucose absorbed through lining of the mouth
- after breakdown to glucose, galactose and fructose , hose monosaccharides are absorbed
- cells usually convert galactose and fructose to glucose
-most adsorpotion happen in the small intestine - absorption of monosaccarches = increase in blood sugar
how many calories are in 1 gram of carbs
4 calories
Carbohydrate
Metabolism
-most goes to energy - 50 % or more of CHO goes to supply body with energy
- excess is converted to triglycerides and stored as fat
-Polysaccharides -> disaccharides -> monosaccharides
-Another 10% or more goes to the blood
glucose, liver, and muscle glycogen stores
-muscle and liver stores about 300g of glycogen only enough for a few hours
- if one does not have enough CHO intake then the body breaks down Pro to make CHO
Carbohydrate
Metabolism
-Not enough CHO intake? Then we need to use
protein or fat
-The body needs minimum 50-100g CHO day to
avoid protein and fat use
-Fat fragments are converted to ketones, which
the brain, nervous system and muscles use
-130g minimum is recommended
-This can cause ketosis and disturbs the acid base balance
* CHO needed for full metabolism of fat, gluconeogenesis happens in the liver to synthesize
glucose
blood sugar
- this is where all cells get their sugar and thus energy from
- blood brigs glucose by continuously from the small intestine (food) or the liver
(glycogen breakdown or glucongenesis - body must maintain BG within limits that permit cells to get adequate energy
insulin
- the hormones active when BG is high
- move GLU into cells to decrease BG
- GLP - 1 = a hormone that stimulates satisfy, released in lower GI tract; refined and processed CHO absorbed in upper GI does not stimulate GLP-1