bobo0100 wrote:
Was Brimstone trying to suggest that the consumption of cholesterol is "bad" due to the fact the the body will need to transport it via LDL or HDL so it doesn't matter if its LDL or HDL because that is not necessarily how the body will transport it in the end?
Yes, that is my understanding.
Saying that consuming HDL cholesterol will raise your HDL levels would be like saying eating hair would help your hair grow -- or even that eat blonde hair would make you grow blonde hair, eating black hair would make you grow our black hair, etc.
Take that with a grain of salt, though. I can't reference anything to back that up, and I'm not certain on that one.
bobo0100 wrote:
Is dietary LDL and HDL levels worth differentiating between at all? why?
I don't think so, no. It would be like differentiating between dietary rotini and penne pasta. AFAIK.
bobo0100 wrote:
So saturated fat is more important than cholesterol, but especially when combined with cholesterol?
Saturated fat is more important, yes. With or without cholesterol.
Cholesterol is bad too, with or without saturated fat.
Because cholesterol is of low solubility, and your body needs to transport it with HDL or LDL, if you eat a huge amount of cholesterol compared to eating just a little bit, it doesn't make a lot of difference.
At least, that is my understanding.
You are limited in your ability to uptake cholesterol from your diet. Eating a little is about the same as eating a lot. But eating none is better.
It's kind of like there's a uptake cap.
Saturated fat is more important because there is no limit (or, at least, the cap is much higher) to how much harm it can do to you. Eating more is just worse and worse for you.
bobo0100 wrote:can someone better explain what role saturated fat has to play in this. Why does it effect LDL levels?
Your body produces more cholesterol, and possibly metabolizes cholesterol more poorly too, when you consume higher amounts of saturated fats.
"Why?" is kind of the question of the hour.
It comes down to, as I understand it, a mix of gene expression (which involves another "why" that is evolutionary, and varies a lot between people), good old metabolism, and other factors.
Here's an interesting answer given on research gate which broke it down:
http://www.researchgate.net/post/How_do ... holesterol
1. Oxidation of saturated fatty acids can provide acetylcoA for cholesterol biosynthesis. Also check during VLDL packing which fatty acids are preferred for cholesterol esterification (sat or unsat).
2. Saturated fatty acids can alter cell signaling by changing membrane fluidity that can result in change in cholesterol metabolism (synthesis and lipoprotein distribution).
3. Fatty acids can regulate cholesterol metabolism by providing signaling molecules like arachidonic acids, prostaglandins, cyclins, anandamides, etc. Generally these are synthesized from unsaturated fatty acids. But saturated fatty acids can competitively inhibit the enzymes involved in synthesis of these molecules (I think). Look for this connection in literature.
4. Fatty acids can directly regulate gene expression by acting as ligands for PPARs. PPARs role in cholesterol metabolism is well known. Here also unsaturated fatty acids are better ligands than saturated fatty acids. Look in this angle.
That
seems credible to me. Again, though, grain of salt.
Why more LDL rather than HDL? Probably the same kind of answer. Gene expression and all of that.
These are certainly important questions, but they're ones that medical science needs to answer. They're unimportant for us to merely explain that saturated fat is unhealthy because is raises total and LDL levels. This is a well documented cause and effect.
We don't need to know why being shot with bullets causes death, for example, to say that it overwhelmingly does. It's a causative link, and knowing the mechanism of action isn't essential to establishing beyond a reasonable doubt that point.
Correct me if I am misunderstanding anything.