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31 Cards in this Set
- Front
- Back
Name the essential FA's
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Linoleic 18:2 (n-6)
alpha-linolenic 18:3 (n-3) |
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Trans fatty acids occur in modest amounts in meat and dairy products as result of bacterial fermentation. Catalytic hydrogenation of polyunsaturated vegetable oils to convert these oils to a hardened form of margarine that has the texture of butter is a significant source of trans fatty acids.
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saturated fatty acids and trans unsaturated fatty acids raise levels of LDL (low density lipoprotein), which increases risk of coronary heart disease (CHD). But, unlike the saturated fatty acids, the trans acids also lower blood levels of HDL (high density lipoprotein) a molecule deemed protective against CHD
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Essential FA deficiency
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scaly dry skin
RBC fragility, decreased myocardial contracitlity and resistance to capillary blood flow, decreased ATP from liver mito skin fixed through omega-6 more than omega-3 |
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Diagnosis of essential FA deficiency
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FA oleate is elongated and desaturated to make 20:3 omega-9, the closest approximation to the eicosanoid 20:4
TRIENE/TETRAENE ratio 20:3 to 20:4 ratio above .1 = eFA deficiency |
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Who gets it
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geriatrics on poor diets
fat malabsorption syndromes(surgical bowel resection) parenteral nutrients deficient in eFA Burn patients |
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eFA and pregnancy
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Should be 1% of total energy
in preg should be 3% |
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What breaks down triglycerides?
phospholipids? cholesterol oleate? |
Tg, lipase
phospholipid, phospholipase cholesterol, esterase |
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Explain digestion and absorption of TG's (LCFA)
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TG combine with bile acids and phospholipids to emulsified droplets
add in lipase and esterase and get mixed micelles (LCFA, 2-MG(monoacylglycrol)) these are absorbed by intestinal villus cells (bile acids leave to be reabsorbed in the enterohepatic circ) FA+MG -> TG -> chylomicrons (VLDL,LDL,HDL) which empty into lymph -> thoracic duct -> blood |
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digestion/abs of Tg is almost complete, sterols are not
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kjb
sterols and CE incorp into mixed micelles most CE is secreted, |
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digestion and absorption of TG's(MC/SCFA)
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abs dir into cells. FFA go to portal vv (bound by albumin)
4X as efficient abs do not facilitate lipid-soluble vit |
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Lingual lipase
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dont do much with LCFA
pancreatic lipase and colipase, max activity above pH7 1:1 molar ratio colipase - binds lipase to TG droplet displacing bile salt |
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bile salts activate what enz
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cholesterol esterase, rate of hydrolysis is much less than for TG's
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specificity of sterol absorption
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beta sitosterol from plants abs poorly, plant sterols interfere with cholesterol abs
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beta-sitosterolemia
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1/3 of dietary sitosterol is abs(instead of 5%) --> deposits found in many tissues, plasma CE is normal
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fatty malodorous stools
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steatorrhea
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what are some situations assoc with steatorrhea
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1)pancreatic disease
2) insuff bile production(duct obstruction)/poor liver secretion(hep) 3) loss of small intestine segm 4) celiac disease and sprue (immune response to gluten, damage to intestinal villi) |
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how can you diagnose celiac disease/sprue
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measure fat soluble vit in blood, test stool for fat
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metal soaps
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FA in lumen bind divalent cations like Ca Mg and Zinc
can't abs them |
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Oxalates
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decrease Ca in intestine means increase abs of plant oxalates, a major source of kidney stones
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what can you give a patient who has steatorrhea
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remove dietary fat and replace with MC triglycerides (MCT), can be abs w/o pancreatic lipases
octanoic and decanoic acids are abs dir via portal vv |
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cholesterol usual uptake
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200-600 mg/day
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macronutrients abs'd where?
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jejunum
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B12/bile salts abs'd where
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ileum
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water soluble vitamins absorbed where
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upper intestine
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whats more important in atherosclerosis and diet
dietary fat or cholesterol |
dietary fat
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diet can effect
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LDL/HDL ration, want low LDL
and changes in suseptibility to thrombosis(clotting) |
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P/S ratio
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polyunsat/ sat FA's
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What type of fatty acid do you want to be eating? (sat vs unsat) and why
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saturated = more atherogenic
PUFA's (and oleic)are less atherogenic Fish oil omega-3 are more antiatherogenic than other PUFA's |
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Blood cholesterol
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200 mg/day is risk factor, over 240 requires serious intervention
measure LDL levels, HDL not a risk |
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soft or hard margarine
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hard margarines are worse
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Homocysteine and atherosclerosis
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effects not well understood, may be from superoxide radicals,
Hcys levels determined by the rates with which it is recycled to met(using 5,methylTHF-->THF and B12) or cysteine(B6) Tetrahydrofolate - normalize Hcys B6/B12 defic = hyperHomocysteinemia |