By Richard N. Fogoros, MD 

 Medically reviewed by Anisha Shah, MD

High levels of HDL cholesterol, often called "good" cholesterol, are associated with a reduced risk of coronary artery disease (CAD). It appears that HDL particles "scour" the walls of blood vessels, cleaning out excess cholesterol that otherwise might have been used to make the plaques that cause CAD. The HDL cholesterol is then carried to the liver, where it is processed into bile, and secreted into the intestines and out of the body.

So, the current theory goes, when we measure a person's HDL cholesterol level, we are measuring how vigorously his or her blood vessels are being "scrubbed" free of excess cholesterol.

SolStock / iStock

Interpreting HDL Cholesterol Levels

HDL levels below 40 mg/dL are associated with an increased risk of CAD, even in people whose total cholesterol and LDL cholesterol levels are normal. HDL levels between 40 and 60 mg/dL are considered "normal," and do not very much affect the risk of CAD one way or the other. However, HDL levels greater than 60 mg/dL are actually associated with a reduced risk of heart disease.1

In other words, the dogma has been: the higher the HDL levels, the better.

While this belief is still thought to be almost always true, in recent years a fly has been found in the ointment. Drug companies have spent billions of dollars developing drugs that increase HDL cholesterol levels. However, to the dismay of all, these drugs have failed to reduce cardiac risk—despite the fact that they make HDL levels go up. Development of at least two of these drugs has now been halted. (More on this below.) So the HDL story is more complex than scientists originally had hoped.

How Can We Increase Our HDL Levels?

Fortunately, it is still true that when HDL levels are increased “naturally” (that is, not from taking drugs), these higher HDL levels are indeed associated with a reduced risk of cardiovascular disease. So, how can we increase our HDL levels in a beneficial way?

Aerobic Exercise

Many people don't like to hear it, but regular aerobic exercise (any exercise, such as walking, jogging or bike riding, that raises your heart rate for 20 to 30 minutes at a time) may be the most effective way to increase HDL levels.2 Recent evidence suggests that the duration of exercise, rather than the intensity, is the more important factor in raising HDL cholesterol. But any aerobic exercise helps.

Lose Weight

Obesity results not only in increased LDL cholesterol but also in reduced HDL cholesterol. If you are overweight, reducing your weight should increase your HDL levels.3 This is especially important if your excess weight is stored in your abdominal area; your waist-to-hip ratio is particularly important in determining whether you ought to concentrate on weight loss.

Stop Smoking

If you smoke, giving up tobacco will result in an increase in HDL levels (This is the only advantage I can think of that smokers have over non-smokers — it gives them something else to do that will raise their HDL.) Read about smoking cessation.4

Cut Out the Trans Fatty Acids

Trans fatty acids are likely present in many of your favorite prepared foods— anything in which the nutrition label reads "partially hydrogenated vegetable oils" — so eliminating them from the diet is not a trivial task. But trans fatty acids not only increase LDL cholesterol levels, but they also reduce HDL cholesterol levels. Removing them from your diet will almost certainly result in a measurable increase in HDL levels.5 

Increase the Monounsaturated Fats in Your Diet

Monounsaturated fats, found in canola oil, avocado oil, or olive oil and peanut butter can increase HDL cholesterol levels without increasing the total cholesterol.6

Add Soluble Fiber to Your Diet

Soluble fibers are found in oats, fruits, vegetables, and legumes, and result in both a reduction in LDL cholesterol and an increase in HDL cholesterol. For best results, at least two servings a day should be consumed.

Other Dietary Means to Increasing HDL

Cranberry juice has been shown to increase HDL levels. Fish and other foods containing omega-3 fatty acids can also increase HDL levels.7 In postmenopausal women (but not, apparently, in men or pre-menopausal women) calcium supplementation can increase HDL levels.

What About a Low-Fat Diet?

Substantial evidence now shows that a low-fat diet often reduces — rather than increases — HDL levels. This result is not specifically caused by “not enough fat,” but rather, is caused by consuming too many carbohydrates. The American Heart Association and the American College of Cardiology have quietly stopped recommending low-fat diets for heart disease prevention. Indeed, it is low-carb diets — and not low-fat diets — which are associated with higher HDL levels.

What About Drugs?

Drug therapy for raising HDL cholesterol levels has, so far, been a disappointment. While enthusiasm for drugs that would increase HDL levels was high just a few years ago, recent events have significantly dampened that enthusiasm.

Statins, the class of drugs which has proven highly successful in reducing LDL cholesterol, are generally not very effective at increasing HDL levels.

For years, niacin was the mainstay of drug therapy for raising HDL levels. Niacin is one of the B vitamins. The amount of niacin needed for increasing HDL levels is so high, however, that it is classified as a drug when used for this purpose.

Aside from the inconvenience of taking niacin, two recent, highly-anticipated clinical trials have suggested that raising HDL levels with niacin failed to demonstrate any improvement in cardiovascular outcomes.8 Furthermore, treatment with niacin was associated with an increased risk of stroke and increased diabetic complications. At this point, most doctors are very reluctant to prescribe niacin therapy for the purpose of raising HDL levels.
Perhaps most disappointing of all, a new class of drugs (the so-called CETP-inhibitors), which several pharmaceutical companies have been enthusiastically developing for several years to raise HDL levels, has become a great disappointment. While these drugs do indeed increase HDL levels, they have not demonstrated an ability to improve cardiac risk — and on the contrary, studies appear to show a worsening in cardiac risk with some of these drugs. It is unclear today whether any CETP-inhibitors will ever reach the market.

Sources

Ahmed HM, Miller M, Nasir K, et al. Primary Low Level of High-Density Lipoprotein Cholesterol and Risks of Coronary Heart Disease, Cardiovascular Disease, and Death: Results From the Multi-Ethnic Study of Atherosclerosis. Am J Epidemiol. 2016;183(10):875-83. doi:10.1093/aje/kwv305

Wang Y, Xu D. Effects of aerobic exercise on lipids and lipoproteins. Lipids Health Dis. 2017;16(1):132. doi:10.1186/s12944-017-0515-5

Ryan DH, Yockey SR. Weight Loss and Improvement in Comorbidity: Differences at 5%, 10%, 15%, and Over. Curr Obes Rep. 2017;6(2):187-194. doi:10.1007/s13679-017-0262-y

Gepner AD, Piper ME, Johnson HM, Fiore MC, Baker TB, Stein JH. Effects of smoking and smoking cessation on lipids and lipoproteins: outcomes from a randomized clinical trial. Am Heart J. 2011;161(1):145-51. doi:10.1016/j.ahj.2010.09.023

Katan MB, Zock PL, Mensink RP. Trans fatty acids and their effects on lipoproteins in humans. Annu Rev Nutr. 1995;15:473-93. doi:10.1146/annurev.nu.15.070195.002353

Pérez-jiménez F, López-miranda J, Mata P. Protective effect of dietary monounsaturated fat on arteriosclerosis: beyond cholesterol. Atherosclerosis. 2002;163(2):385-98. doi:10.1016/s0021-9150(02)00033-3

Preston mason R. New Insights into Mechanisms of Action for Omega-3 Fatty Acids in Atherothrombotic Cardiovascular Disease. Curr Atheroscler Rep. 2019;21(1):2. doi:10.1007/s11883-019-0762-1

D'andrea E, Hey SP, Ramirez CL, Kesselheim AS. Assessment of the Role of Niacin in Managing Cardiovascular Disease Outcomes: A Systematic Review and Meta-analysis. JAMA . 2019;2(4). doi:10.1001/jamanetworkopen.2019.2224

Additional Reading

• Nicholls SJ, Brewer HB, Kastelein JJ, et al. Effects of the CETP Inhibitor Evacetrapib Administered as Monotherapy or in Combination with Statins on HDL and LDL Cholesterol: a Randomized Controlled Trial. JAMA 2011; 306:2099. 

• Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults: a Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014; 129:S1.

• The AIM-HIGH Investigators. Niacin in Patients with Low HDL Cholesterol Levels Receiving Intensive Statin Therapy. N Engl J Med 2011; 365:2255-2267 DOI: 10.1056/NEJMoa1107579.

By Richard N. Fogoros, MD
Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.