You've used such a dose of niacin for 8 years straight? Wow! I would love to know your experiences since I have an idea in my head that niacin has anti-aging properties.
I used 3 grams a day for about 25 years, and had no problem with it other than the acidity and the occasional flushing that had people asking me if I had a sunburn. I wasn't aging much at all until someone convinced me that it caused liver damage. So I stopped, and began to age rapidly as a result (which I only saw in retrospect). Today I take a gram of nicotinamide and a few grams of ribose once a week. This is far better than niacin as an anti-aging NAD+ precursor, and better than NR as well as NR has to be broken down to nicotinamide and ribose to be absorbed, a process that takes several hours.
As for cholesterol, the hysterical fear of this important substance has been whipped up by the drug industry, which has created a modern version of bloodletting. High cholesterol is a very minor risk factor for younger people, and for older people, it appears to be protective, especially if one doesn't smoke and has systolic pressure under 140. For women, it's not a problem at all. For men, there is a best cholesterol level, but it's in what's normally considered a high range.
See these large scale studies--
From a New Haven study with 1000 participants--
Our findings do not support the hypothesis that hypercholesterolemia or low HDL-C are important risk factors for all-cause mortality, coronary heart disease mortality, or hospitalization for myocardial infarction or unstable angina in this cohort of persons older than 70 years.
https://www.ncbi.nlm...ticles/7772105/
A Japanese study with more than 3,500 participants, ages 71-93--
Relative risks for mortality were 0.72, 0.60, and 0.65, in the second, third, and fourth quartiles, respectively, with quartile 1 as reference.
https://www.ncbi.nlm...holesterol 2001
And the Norwegian HUNT 2 study was the largest of all, with 52,000 participants who were followed for ten years. They concluded—
If our findings are generalizable, clinical and public health recommendations regarding the ‘dangers’ of cholesterol should be revised. This is especially true for women, for whom moderately elevated cholesterol (by current standards) may prove to be not only harmless but even beneficial.
So if higher cholesterol is good for people past a certain age, then the question asked in the OP is a good one. Should it be taken as a supplement by certain people, and what is the best source of it? Certainly there is a lot of cholesterol being recycled, but how much is being made by the liver and how much is consumed? I see one source saying 1-2 g are produced daily, but doesn't give a reference.
Edited by Turnbuckle, 25 March 2017 - 12:10 PM.