Originally Posted by dakayus  Well I'll just give you some info
niacin is good for lowering cholesterol and statins do work very well, but they have some bad consequences and actually current research doesn't really support it either way. Actually the professor in one of my classes who is a cardiologist actually stopped taking statins because of a recent article that I can't find. Either way I'll just cut and paste some of my notes from a class to hopefully help you, but let met just say ldl is an ldl or low density lipoprotein and hdl's are high density. the difference is that hdl's are smaller so they're higher density since they're composed of a coat that's more dense than the containing cholesterol and become ldl's when they're larger. The hdl's scavenge the body for ldl's, when there's tons of hdl's, to help shrink the size.
Lack of fat in diets of rats
Scaly skin, kidney damage, impaired fertility, lived poorly, and died early
Later they gave them some vegetable oil and found out about essential fatty acids
· Fatty Acids
○ C (then a number) ; (another number) w-(a number) or n-(a number)
○ Example C18;0 18 carbons 0 double bonds
○ Example: monounsaturated MUFA
○ Example: saturated fatty acids SFA
○ Example: polyunsaturated PUFA
○ Know how to use this so how to draw given something like CX;X w-X
○ The number is where the first double bond starts
○ i.e. Linoleic acid C18:2(w-6) the w-6 means it starts at the 6 position
○ Know alpha-linolenic acid C18:3(w-3) aka omega 3 aka ALA
○ Chains
§ Long chain >11 carbons
§ Medium chain 6-10 carbons
§ Short chain <6 carbons
§ The shorter the chain or more saturation, the lower the melting point
§ Animal fat: more saturated and so solid at room temp
§ Vegetable oil: more polyunsaturated fats and is liquid at room temp
○ Metabolism
§ Triglycerides>(lipases)> fatty acids & glycerol
§ Fatty acid goes into cytosol and goes into mitochondria for fatty acid oxidation which requires carnitine (shoves it through membrane of mitochondria)
§ Broken down by beta oxidation which requires vitamin B2 (flavin)
□ Introduces a double bond - dehydrogenation with B2 aka FAD
□ Hydration with water which adds a hydroxyl group basically
□ Oxidize it with NAD+ to a ketone NAD+ is niacin vitamin B3
□ Thiolysis (using SCoA) so you have acetyl CoA
□ Acetyl CoA goes to TCA cycle
○ Synthesis
§ Occurs in the cytosol 2 carbons at a time
§ It usually finishes with palmitic acid C16:0 then it's ready to be modified
§ The cell uses enlongases and desaturases to change up the fatty acids ready for the body to use
§ Linoleic Acid C18:2(w-6) omega 6 fatty acid aka LA
§ We can't make double bonds in the fatty acids before alpha 9 carbon so if we need it, we have to eat it. Thus they are essential fatty acids
○ Omega fats
§ Omega 6 is common in seed vegetable oils
§ Omega 3 has high concentration in plant leaves, which we don't make oil out of, and not common in seed oil except flax seed oil, hemp seed, walnut, canol
§ Hemp seed oil is 3:1 omega 3 to omega 6 which is ideal for health
§ Omega 6 - linoleic acid - makes arachidonic acid C20:4(w-6)
§ Omega 3 - alpha-linolenic acid - goes to EPA, C20:5(w-3), then further converted to DHA C22:6(w-3) which are precursors to eicosanoids (prostaglandins) which are key signaling molecules in our bodies.
§ Eicosanoids - do pain inflamation, digestion, etc etc
§ Arachidonic acids (from w-6) uses cyclooxygenases (COX) and LOX
□ COX inhibitors, NSAIDS, block the formation of these
§ Group 2: AA (w-6) promote inflammation and blood clotting. Too much can causes hardening of arteries and such
§ Group 3: are competitive inhibitors of group 2. Dampen inflammation and thin blood. Beneficial for cardiovascular diseases. Too much leads to hemorrhagic strokes. You need some coagulation to control bleeding, or whatever which causes the strokes.
§ Thus eating omega-3 will lessen cancer, cardiovascular diseases, arthritis, etc.
§ W-3 tend to inhibit W-6's conversion and vice versa
§ DHA - found in the retina and the brain and is the last lipids the body will let go of. Good for heart function, brain function, and eye sight. It slows memory loss and increase I.Q. (6 points higher on average) Also linked with better social behavior. This was done in pregnant mothers for 15 years.
§ Ratio of w-6 to w-3 has decreased significantly over the years (w-6:w-3)
□ Pre-ag times: about 1:1
□ Currently: 10-15:1
□ Recommended is like 2-3:1
□ The more double bonds the more unstable so manufactures try to eliminate it (more prone to becoming rancid)
§ Conversion of w-3 to EPA and DHA is really inefficient
□ Seafood is a good source of EPA and DHA hence seafood diets
§ Omega-3 in fish
□ Problems with fish
¨ Mercury, pollutants
¨ The highest pollutants are the ones at the highest level of the food chains
¨ High levels found in swordfish, shark,
¨ Highest levels of omega-3 (don't need to know, just nice to have)
◊ Atlamtic salmon
1.8
◊ Anchovy
1.7
◊ Sardines
1.4
◊ Rainbow trout
1.0
◊ Coho salmon
.9
◊ Bluefish
.8
◊ Striped bass
.8
◊ Tuna, white, canned
.7
◊ Halibut
.4
◊ Catfish, channel
.2
Niacin
Know it's structure it's NAD(P)+ and NAD(P)H
It's a pyridine derivative
Deficiencies- pellegra (skin was broken), dementia, dermatitis, diarrhea
Takes 50-60 days
Lime (CaOH) is needed to make niacin available from corn since it's normally bound by protein
Main food sources in the south: corn, salted pork, black-eyed peas.
Niacin was unavailable in the corn, the salted pork was mostly fat, and the black-eyed peas had low niacin. (many people died from this).
More modern usage is to treat atherosclerosis at high levels of 1.5-2.0 g/day
This raises HDL and lowers LDL
Side affects include flushing, G.I. problems, and liver damage
normally RDA is 14-19 mg/day and UL 35 mg/day
have fun.
doctors are usually correct though, but do make mistakes
(I'm currently a med student)
hope this helps |