functional hypocholesterolemia due to very high HDL or low LDL?

Question

Nutritional and medical recommendations about cholesterol seem to focus exclusively on hypercholesterolemia, and as such, they provide only a maximum desirable level for LDL and a minimum for HDL. I've found a little bit of information about hypocholesterolemia caused by inadequate cholesterol in the body (due to overuse of statins, malnutrition, or other disorders), but not about cholesterol deficits due to lipoprotein levels.

It seems like it should be theoretically possible to have so much HDL or so little LDL activity that organs don't maintain enough cholesterol to function properly, even if cholesterol synthesis is adequate. Obviously this might or might not ever occur in reality. Is there any research that has found an upper bound on desirable HDL in humans, or a lower bound on desirable LDL or LDL:HDL ratio?

Answer 1

Upper bound of HDL doesn't really exist. The greeks are known for their incredibly high levels of HDL and the so called mediterranean diet/genetics combination that causes this is only beneficial to health (supposedly - although never been proven that incredibly high HDL levels are beneficial, they're just not harmful).

As for too low LDL levels/cholesterol levels - that's interesting. Unfortunately it isn't possible because any mutations that caused this would be fatal, cholesterol makes up an essential part of cell membranes etc. That's why our body makes our own. A mutation preventing this would not even manifest.