Lipids - Nutrition Flashcards
categories of fatty acids
- saturated
- monounsaturated (MUFA)
- polyunsaturated (PUFA)
where is the caloric content of macronutrient lipids mainly fount
the fatty acids -> acetyl CoA and generate ATP
9 kcal/g
different chain lengths of FA, what is the significance?
Long 14+ carbons
Medium 6-12 C
Short 2-4
absorbed in intestine differently
what kinds of fats are found in what plants (generally speaking)?
PUFAs - plants grown in cooler areas
ie soybeans
tropical plants have higher temps of saturated fats w/o having fluidity problems
olive oil, avocados, peanuts, pecans, almonds - monounsaturated fatty acids MUFAs
what fats are found in amimals?
more variability;
warm blooded - saturated fats (beef & pork)
cold water fish - polyunsat FA (esp Omega-3)
what are fats?
triglycerides
dont have phosphate in them
the importance of trans double bond vs cis?
trans bonds dont put a kink in the chain
so act more like saturated FA
some in meat and dairy due to bacterial fermentation
are hydrogenated to form margarine
whats the prob w trans FA?
well, sat and trans unsat fatty acids raise LDL levels
trans unsat FA also lower HDL
so margarine can be worse for you than butter
Linoleic acid
18:2 (n-6)
essential
alpha-linolenic acid
18:3 (n-3)
essential
arachidonic acid
20:4 (n-6)
derived from linoleic acid
why are essential fa important?
bc they are made into prostaglandins and leukotrienes
most of the EFA’s in the brain are…
linolenic (n-3)
essential fa deficiency symptoms;
prominent; scaly skin (n-6 more effective for fixing)
infertility (male and female)
reduced growth rates
increased RBC fragility
etc
(rest can be fixed w either n-3 or n-6 supp)
triene/tetraene ratio
EFA deficiency -> use oleat to make 20:3 n-9 a Triene
Tetraene (20:4) - eicosanoid form from n-6 and n-3
> 0.2 = EFA deficiency
triene/tetraene ratio criterion;
- geriatric, poor diet, esp w peripheral vasc disease
- fat malabsorption
- prolonged parenteral alimentation w formula deficient in EFAs
- burn pts
are EFA’s PUFAs or MUFA’s?
PUFAs
note; not all PUFA are essential
DHA (docosahexaenoic acid)
imp constituent of breastmilk
LCFA imp for neurla development
colipase
protein that anchors the pancreatic lipase to the bile acid emusified droplets to help it do its job
monoacylglycerol (2-MG)
primary digestion products are this + FFA
how are med chain triglycerides absorbed
directly into cells
dont need bile acids
FA bound to albumin
how are cholesterol esters absorbed?
they arent
pancreatic cholesterol esterase must make it into free cholesterol
free cholesterol is absorbed after being solubilized in bile salt micelles
how much of dietary cholesterol is excreted?
2/3
describe plant sterol absorption
high dietary plant sterols interfere w cholesterol absorption
found in butter-replacement products
steatorrhea
fatty and malodorous stools
situations assoc w steatorrhea
- pancreatic disease
- insufficient bile production - gall bladder, cystic duct obstruction, poor liver secretion
- loss of lrg seg of small intestine
- damage to intestinal villae (ie celiac)
- failure of chylomicron synthesis
72h fecal fat test
greater than 7% excretion than intake = fat malabsorption
problem w having unabsorbed digestion products like FA in the lumen of the intestine
interfere w absorption of various divalent cations
ie Ca, Mg, Zn
what is most imp interms of increased incidence of atherosclerosis
dietary fat
far moreso than cholesterol
___ are more atherogenic
saturated FA & trans FA
PUFA and MUFA are less atherogenic
antiatherogenic
fish oil fatty acids (20:5 and 22:6, omega-3 PUFA)
mediterranean diet
?
homocysteine and artherosclerosis
correlated for inc risk for cardiovascular disease
inc in thrombosis
folate normalizes levels
B6 B12 deficiencies predispose to hyperhomocysteinemia
currently believe CV risk doesnt respond to B-vitamins
