There are many ways to assess heart disease risk, including lipid and cholesterol measures. The focus of this article is HDL-Cholesterol, but I have written similar articles about LDL-Cholesterol (available here) and Triglycerides (available here).
What Is HDL-Cholesterol?
High density lipoprotein (HDL) is a carrier molecule for cholesterol, phospholipids and triglycerides.
Think of HDL as a boat.
Cholesterol is the cargo.
Remember the cholesterol (cargo) can’t float in the blood; it needs to be carried around by the lipoprotein (the boat). Therefore, HDL-C is how much cholesterol (cargo) is on the HDL (boat). There can be varying amounts of cargo on each boat. As you’ll soon learn, it is beneficial to have a high HDL-C. In other words we want a lot of cargo on the HDL boats.
HDL can carry varying amounts of cholesterol. In fact, its benificial to have a higher HDL-C.
What Does HDL Do?
HDL carries cholesterol away from cells and takes it to the liver to either be removed from the body or reused. The process of taking cholesterol from the peripheral tissues back to the liver is called reverse cholesterol transport , . On the other hand, low density lipoprotein (LDL), takes cholesterol to the cells. The reason LDL is considered ‘bad’ is because when cholesterol is attached to it, that cholesterol is susceptible to damage and may contribute to atherosclerosis, and subsequently heart disease.
It's important to remember cholesterol is not inherently bad, it just happens to be susceptible to damage. In fact, click here to learn about the Truth About Cholesterol and Eggs and click here for an article about How We Got Misled about Cholesterol.
Why Do We Want to Increase HDL-C?
As mentioned above, HDL basically cleans up the blood and cells of cholesterol, thus minimizing the cholesterol’s chance of being oxidized or damaged.
There are many established risk factors for heart disease. Diagnoses such as obesity, diabetes, kidney disease, and hypertension are just a few co-morbidities that increase cardiovascular disease risk . Certain blood lipids will be tested and associated with risk. HDL-C is considered a negative risk factor  – meaning it protects against heart disease .
HDL is anti-inflammatory , , minimizes oxidative stress  , inhibits cells in the blood from sticking to each other  and possibly plays a role in improving diabetes and glucose metabolism  . So you can see why we want HDL to be high. For HDL to have its protective effect, we aim to keep it above 1.55 mmol/L (60 mg/dL) .
Low HDL-C is associated with hypertriglyceridemia, diabetes, overweight/obesity, physical inactivity, cigarette smoking, very high carbohydrate intake, certain drugs (beta-adrenergic blockers, anabolic steroids, progestational agents), and genetic factors .
Diet Interventions that Increase HDL-C
1. Lower Carb/Higher Fat Diets
- Lowers triglycerides, raises HDL-C 
- LDL-C may not change in concentration but the molecule shifts to the larger, buoyant one 
- Low carbohydrate = less than 50 grams a day (or less than 10% of total energy)
- High fat diets have very few reported adverse effects and little to no effect on blood lipid levels
- Added benefit – more weight loss than low-fat diets over 6 months 
- Low carb/high fat diet on obesity (still low calorie diet): improve HDL, lowers inflammatory markers (CRP) 
- Low carb/high fat diet on Metabolic Syndrome: extreme improvement in LDL, body weight, BMI, waist circumference, fasting blood sugar, triglycerides, blood pressure, and HDL 
- Low carb/high fat diet on Type 2 Diabetes: substantial improvements to weight loss, HbA1c, fasting glucose, blood glucose stability, reduced diabetes medications needed, better lipid profiles (increased HDL, reduced triglycerides) 
2. Influences of Dietary Fat on Blood Lipids
- Fatty fish reduces triglycerides; helps HDL, LDL, blood pressure  ; reduces triglycerides in both hyper- and normo-triglyceride populations 
- Eating fish at least 4 times a week increases HDL in those with heart disease 
- Avoid artificial hydrogenated Polyunsaturated Fatty Acids (vegetable oils such as corn, soybean oil, margarine, canola)
o Studies show they reduce HDL  and worsen LDL profiles 
- Avoid trans-fats
o Raise TC and LDL-C; lower HDL-C , 
o Sources of TFAs are partial hydrogenation of vegetable oils: margarines, shortenings, commercially fried foods, baked good
3. Soluble Fiber helps HDL
- Soluble fiber is the non-digestible carbohydrate component of plants, and it has an inverse association with cardiovascular disease risk 
- Examples are: Beans, oats, barley, fruits, vegetables
- Additional 5-10 grams per day to one’s diet may reduce LDL-C by about 5%
4. Plant sterols (stanols/sterols)
- Phyosterols come from nuts, seeds, vegetable oils 
- Phyosterols lower LDL-C independent of dietary cholesterol intake
- Supplements exist which provide a dose required to have this therapeutic effect
- Helpful for use with statin drugs, especially when statins are about to increase in dose. Try adding this instead 
3. Olive Oil
- 15 grams was able to protect LDL from oxidation and raise HDL  and lower total cholesterol-to-HDL ratio, lower triglyceride levels and lower oxidative markers 
- Improves antioxidant status: glutathione, superoxide dismutase, catalase 
- Polyphenol content is important; so find brands that have high amounts of polyphenols
Foods that Increase HDL-C
- In both low risk and high risk heart disease patient, have been shown to increase HDL and lower LDL’s contribution to atherosclerosis 
- 10 grams before breakfast, in patients with coronary artery disease increased HDL by about 15%
- Omega-3 fatty acids EPA and DHA – sources are fish oil, fortified foods, supplements
- Improves HDL and Total Cholesterol/HDL ratio and inhibits LDL-C oxidation
- Helpful in both prevention and treatment of coronary artery disease 
Lifestyle Factors that Increase HDL-C?
- High intensity exercise is best for blood pressure, lipoproteins and triglycerides compared to endurance alone or low intensity exercise 
- Aerobic exercise is effective too – TG reduction by 12%, HDL-C increase of 4.1% in overweight, obese individuals
2. Weight loss
- 5-10% weight loss results in 15% reduction of LDL, 20% reduction of triglycerides and 8-10% increase in HDL-C 
- For some, during the weight loss phase, HDL may go down, but once weight loss is maintained it will normalize, higher than it was 
- Especially in obese/overweight people, alternate day fasting and endurance exercise. Body mass index reduced, fat mass, waist circumference decreased, lean mass retained, LDL particle increased, HDL increased 
- 3% weight loss is enough in obese and overweight people to see improvements to all cholesterol, liver function, and sugar levels 
3. Limit Alcohol and drink wisely
- Alcohol has both positive and negative associations to heart disease risk
- Overconsumption leads to alcoholism, hypertension, obesity, stroke, breast cancer, suicide, and accidents
- alcohol lowers fibrinogen (a clotting factor) – which would therefore reduce certain risks 
- The recommendation is to continue drinking responsibly but not to start drinking just to gain this benefit
Take Home Message
HDL is a very important lipid marker and a strong predictor of overall heart health. There are a number of ways known to significantly affect HDL-cholesterol levels, from diet and food to supplements.
For more information about supplements, and for a more indepth discussion and analysis into your heart health, book in by clicking here.
About the Author
I'm Johann de Chickera, a Naturopathic Doctor, practicing in Ontario, Canada. My clinical practice relies on keeping up with the most up-to-date research and continued education. This blog serves as a way to provide others with a compilation of everything I've learned along the way. Please click here if you're local and want to see me in practice.