HDL “Good” Cholesterol Explained
On many occasions, I’ve heard family, friends, and strangers alike who have expressed concerns over their low HDL cholesterol levels. They’re worried something is wrong with them, and they want to do something about it. This often involves taking a pill to increase their HDL level.
I thought it would be helpful to explain what HDL cholesterol is, how it works, and how well the approach of taking a pill to correct low HDL levels has worked so far.
What is HDL Cholesterol?
High-density lipoproteins (HDL) are a form of cholesterol referred to as “good” cholesterol. That’s because HDL cholesterol is associated with lowering our risk of cardiovascular disease (CVD).
This lower risk of CVD was first discovered back in the 1950s, but really came to light in 1977 when the famous Framingham Heart Study showed a correlation between low HDL levels and higher rates of cardiovascular disease and cardiovascular deaths. 
What Does HDL Cholesterol Do in the Body?
HDL cholesterol carries out many functions in the body. It is far more complex than most people think. Scientists haven’t even unearthed the whole story yet, but below are some of the things we’ve learned about the role of HDL in the human body: 
Primary role of HDL – To transport excess cholesterol from the blood back to the liver to be disposed of from the body (via bile fluid) through the feces.
Secondary roles of HDL
- Potential anti-inflammatory properties on the cardiovascular system
- Antioxidant effects within the cardiovascular system
- Prevention of atherosclerotic plaques
- Stabilization of already formed atherosclerotic plaques (this prevents plaque ruptures and blood clots which can cause strokes and heart attacks)
The primary role of HDL transporting excess cholesterol back to the liver for disposal can be thought of with a simple analogy. If you’ve ever visited Bourbon Street in New Orleans then you know after each night of partying there is a ton of trash left on the streets and sidewalks. Somebody has to clean this trash up. That somebody is the garbage men and their trucks that come by in the morning to make things look nice again. HDL works in the same manner as these garbage men and their trucks. They “clean up” the extra cholesterol in our blood supply that doesn’t need to be there. This excess cholesterol is what puts us at risk for heart attacks and strokes.
Using Medication to Raise HDL Levels and Their Success Rates
If low HDL levels are associated with higher rates of cardiovascular disease like the Framingham Heart Study showed us, then it would make sense to raise HDL levels. That’s what we try to do in conventional medicine using medications and supplements. Does this work though?
We can certainly raise HDL levels using pills. We’ve proven that. Three of the most common drugs used to do this are statins, fibrates (fenofibrate, gemfibrozil), and niacin. Statins raise HDL levels by approximately 5-10%, fibrates by 10-15%, and niacin by 25%. 
Despite these increases in HDL levels with drug therapy, we still do not see a reduction in cardiovascular death rates. [1,2] This is unfortunate because the main reason any patient would want to take these medications is to not die from the disease they’re taking the medication for. I call this dying with better numbers.
In addition, with any medication there are always side effects to consider. Statins carry the risk of muscle-related side effects. Niacin can cause flushing causing some people to discontinue it. Fibrates can cause gastrointestinal side effects (nausea, vomiting, diarrhea, etc.) and can also increase muscle-related adverse effects when taken together with statins.
While we have uncovered an association between low HDL levels and higher rates of cardiovascular disease, there is still much to understand about this complex relationship. Raising HDL levels with drugs has not yet benefited patients in terms of reducing cardiovascular death rates like we’d hoped for.
Instead of providing more “garbage men and garbage trucks” to clean up the excess cholesterol in our blood supply, maybe a better idea would be not to put it there in the first place. This can be accomplished by adopting a whole foods, plant-based diet and staying away from a meat- and dairy-heavy Standard American Diet. There simply is no harm in eating vegetables and only good things come to those who do.
Dustin Rudolph, PharmD, BCPS
1 Ali KM, Wonnerth A, Huber K, Wojta J. Cardiovascular disease risk reduction by raising HDL cholesterol – current therapies and future opportunities. British Journal of Pharmacology. 2012;167(6):1177-1194.
2 Kühnast S, Fiocco M, van der Hoorn JW, et al. Innovative pharmaceutical interventions in cardiovascular disease: Focusing on the contribution of non-HDL-C/LDL-C-lowering versus HDL-C-raising: A systematic review and meta-analysis of relevant preclinical studies and clinical trials. Eur J Pharmacol. 2015 Sep 15;763(Pt A):48-63.