At first, I thought it was attributable to other factors. In real life, most people don't modify one factor at a time. They reduce
processed carbohydrates/eliminate wheat and cornstarch, lose weight, add or increase omega-3 fatty acids from fish oil, begin niacin, increase exercise and physical activity. All these efforts also impact on HDL.
Among the many things I do, I consult on complex lipid (cholesterol) disorders (complex hyperlipidemias) in my office. A substantial number of these people carry a diagnosis of hypoalphalipoproteinemia , a mouthful that simply means these people are unable to manufacture much apoprotein A1, the principal protein of HDL cholesterol particles. As a result, people with hypoalphalipoproteinemia have HDL cholesterol levels in the neighborhood of 20-30 mg/dl--very low. They are also at high risk for heart disease and stroke.
Encourage these people to exercise, attain ideal weight, eliminate wheat and cornstarch: HDL increases 5 mg/dl or so.
Add niacin, HDL increases another 5-10 mg/dl.
Perhaps we're now sitting somewhere around an HDL of 35-40 mg/dl--better, but hardly great.
Add vitamin D to achieve our target serum level . . . HDL jumps to 50, 60, 70, even 90 mg/dl.
The first few times this occurred, I thought it was an error or fluke. But now that I've witnessed this effect many dozens of time, I am convinced that it is real. Just today, I saw a 40-year old man whose starting HDL was 25 mg/dl increase to 87 mg/dl.
Responses like this are supposed to be impossible. Before vitamin D, I had never witnessed increases of this magnitude.
Not all therapies for raising HDL raise the important large (also known as HDL2b ) fraction. With lipoprotein analyses, it appears that is principally the large fraction of HDL that rises with vitamin D supplementation.
That I can't tell you. But for those of you struggling with low HDL cholesterols despite your best efforts, vitamin D can make a world of difference.
An interesting corollary: If super-high HDL cholesterols are associated with extreme longevity, as they are with centenarians, does raising HDL to extraordinary levels with vitamin D lead to longer, healthier life, all the way up to age 110 years?
Again, no answers, but an interesting thought. And one I'd bet on. (And I'm not selling vitamin D.)