> "If there are any other causes of obstructive CAD other than fats getting into the artery walls, those cause would all have to be in that group as well (I don't know of any but I can speculate several)."
Here's one speculation of lay-person reasoning:
- Cosmetics people like Retinol skin creams because it makes skin look better. That's a fact that people recommend it.
- One way it does this by making it plumper, which smooths out wrinkles. I think that's a fact.
- It does this by increasing skin cell "turnover", i.e. what it does at the epithelial layer is trigger stem cells to split, making more skin cells, making thicker skin. That's a claim I've seen and am not sure if it's a fact, but it's a plausible mechanism of action.
- We eat retinol in our food, in the form of Vitamin A, that's a fact.
- Vitamin A gets through the guts into the body, that's a fact - it couldn't be a vitamin if it passed straight through us and out.
- Vitamin A gets into the blood stream; fact, there are lab tests of serum retinol levels.
- Vitamin A in the blood is supposed to be wrapped in Retinol Binding Protein to carry it through the blood, but it isn't always. It's normally captured by the liver, and released from the liver wrapped in RBP, but not all of it is captured by the liver and is free in the blood stream. The more of it in the diet, the more gets past the liver, the more of it is free in the blood stream. I've seen it claimed, have no sources to back it up.
- Blood vessels have an epithelial layer on the inside, an internal skin. Claim.
- Retinol in the diet -> retinol in the blood -> triggers stem cell split in the blood vessel walls -> thickening of the walls ("youthful!") -> narrowed blood vessels. Speculation.
(What do we have in this random link[1] I haven't read? "Until recently, it was thought that the sole important retinoid delivery pathway to tissues involved retinol bound to retinol-binding protein (RBP4). More recent findings, however, indicate that retinoids can be delivered to tissues through multiple overlapping delivery pathways, involving chylomicrons, very low density lipoprotein (VLDL) and low density lipoprotein (LDL)" - retinol is not only able to split stem cells, it's a pretty potent molecule in various forms; "Retinoids and immunotherapy may be used to treat high-risk or recurrent neuroblastoma" says Canadian Cancer Society; there's one bro-science connection for increased total LDL -> increased blood vessel damage which is nothing to do with the LDL per-se, but something it carries along with it. Something we eat a lot of as Vitamin A and carotenoids, something the US and Canada fortify flour and low-fat dairy and margarine with, which is another tie-in to both low-wheat and low-fat diet).