Why are some people's cholesterol levels still high even after they adopt a diet low in fat and cholesterol?

katie t, thanks for replying but the question isn't about myself

Agreed with above authors, much of the serum 'bad cholesterol' is endogenous (made in your liver) and as much as we try to alter our lifestyles, our livers make some good things and others which aren't so good, that's why we often see fit, healthy-appearing individuals with very high LDL's who do well with HMG CoA reductase Inhibitors (statins).

There are a number of very serious diseases where patients have exorbitantly high cholesterol from a very young age, with actual stigmata of hyperlipidemia on physical exam. One of my med school professors was actually a pioneer in the discovery and treatment of such patients many years ago where as a young man, he found clusters of families in his native Armenia where familial hyperlipidemias were endemic.

Genetics.

Heredity.

cholesterol levels is partly determined by a genetic predisposition

The first two answers are right. Some people are just genetically programmed to have higher cholesterol and those are the ones for whom the Statin drugs or Niacin are recommended

In some cases stress levels can have an impact on cholesteral, if you are generally stressed this could be the reason. Also if you smoke that could also have an impact.

Because they believe turning to high dosages of vodka and scotch whiskey will reduce their fat in turn it raises cholesterol levels dangerously.

why don't you ask your family doctor? or better yet go to another doctor. It never hurts to get opinions...