Fiber and Lipid Nutrition Flashcards
Oligosaccharides from breast milk are converted to what by gut bacteria?
short-chain FA
Classifications of fiber
soluble: viscous or non-viscous
insoluble: non-viscous
Monosaccharides found in fiber
usually glucose
many other monosaccharides are included in dietary fibers
Lignin structure
insoluble fiber
branched polymers of phenolic subunits, found in stems and seeds of fruits
very undigestible–almost nothing can digest this
Hemicellulose structure
insoluble fiber
linear chain with branches
xylose, mannose, galactose backbone
Pectins structure
soluble fiber
branched polymers
almost completely degraded by gut bacteria
fermented to short-chain FA –> colonocytes
What makes pectins soluble
carboxylic acids
Gums structure
soluble fiber
secreted by plants to close wounds
completely fermented by gut bacteria
Beta-glucans
soluble fiber
fermented by gut bacteria to short-chain FA
Beta-glucans structure
glucopyranose
Fructans structure
soluble fiber
polyfructose
Fructans function
prebiotics
prebiotics, promoting growth of bifidobacteria (gram + anaerobes) in gut
Psyllium function
metamucil
structure similar to gums
indigestible and holds a lot of water
Resistant starch
amylose and amylopectin
inaccessible to amylases or brush border enzymes
Soluble fibers function
delay gastric emptying
increase transit time through GI
decrease nutrient uptake
Insoluble fibers function
decrease intestinal transit time
increase fecal bulk
Viscous fiber function
delay gastric emptying
decrease mixing with digestive enzymes
decrease nutrient uptake
Glycemic index
measure of how quickly you can digest carbs
–> measure blood sugar spike
high fiber –> low glycemic index
Fiber benefits
lipids
bile salts loss because not reabsorbed –> lower cholesterol
feed good microbiome –> short chain FA
increased fecal bulk
Short chain FA functions
feed colonocytes
blunt immune response
Short chain FA activate what on immune cells
GPR43
increases IL-10: blunts immune system response
also transcriptional regulation of histone deacetylases
GPR43 in
adipose
sk muscle
liver
GPR43:
adipose: decrease insulin sensitivity, decrease storage as TAG
sk muscle: increases insulin sensitivity
liver: increases insulin sensitivity
Human breast milk oligosaccharides and bacteria
increase bifidobacteria in colon
can be broken down and used by them
Human breast milk oligosaccharides in circulation
molecular mimicry
binds bad bacteria to prevent them from binding to cells
