HDL Cholesterol

Physiological Role

HDL (high-density lipoprotein) is a particle made up of proteins and lipids, primarily synthesised by the liver and small intestine. Its main function is reverse cholesterol transport. It picks up excess cholesterol from arterial walls and peripheral tissues, returning it to the liver. There, it is recycled or eliminated via bile.

Beyond this transport role, HDL has antioxidant properties. It protects low-density lipoproteins (LDL) from oxidation, a process involved in the formation of arterial plaques. HDL also contributes to maintaining the integrity of the endothelium (the inner lining of blood vessels).

Circulating HDL levels reflect the body's ability to carry out this cholesterol return. Levels vary by sex: women typically have higher concentrations than men, partly due to the influence of oestrogenic hormones. This difference results in distinct optimal thresholds.

Reference Ranges

These reference ranges are derived from scientific literature and may differ from your laboratory's reference values.

Source : ESC/EAS, 2019 Dyslipidemia guidelines (2019)

Biological Significance

An HDL level within the optimal range indicates effective reverse cholesterol transport. This is a favourable indicator for long-term vascular health and overall lipid profile.

Low HDL values are associated with increased cardiovascular risk in major epidemiological studies. Persistently low HDL may signal a lipid imbalance, often accompanied by elevated triglycerides. The overall metabolic context matters: isolated low HDL does not carry the same weight as low HDL combined with elevated triglycerides and increased apolipoprotein B.

Very high HDL values are not necessarily protective. Recent research shows that beyond a certain threshold, HDL may lose its functional properties. Concentration alone does not indicate the quality of particles or their actual capacity to remove cholesterol.

HDL readings gain precision when combined with other lipid panel markers, particularly apolipoprotein B and triglycerides. Trends over time provide more insight than a single measurement.

Influencing Factors

Physical activity. Regular aerobic exercise (brisk walking, swimming, cycling) is one of the most documented levers for supporting HDL levels. Studies observe a dose-dependent increase with weekly activity volume.

Diet. Monounsaturated fatty acids (olive oil, avocado, nuts) and omega-3 fatty acids (oily fish, microalgae) support a balanced lipid profile. Industrial trans fatty acids, on the other hand, are associated with decreased HDL. Moderate alcohol consumption is associated with higher values in epidemiological data, but this link does not constitute a recommendation.

Body composition. Excess visceral adipose tissue is associated with lower HDL. A reduction in waist circumference generally accompanies an improvement in lipid profile.

Smoking. Tobacco reduces HDL levels in a dose-dependent manner. Smoking cessation is followed by a gradual rise in HDL over the following months.

Sex and hormones. Women have higher HDL concentrations than men, under the influence of oestrogens. Menopause is generally accompanied by a decrease in HDL.

Genetics. Genetic variants influence HDL concentration, particularly the CETP, ABCA1 and LCAT genes. The hereditary component accounts for a significant portion of inter-individual variability.

Supplementation. Omega-3 (EPA+DHA) are among the bioactives whose effect on lipid profile is documented. EPA and DHA contribute to the normal function of the heart.

In the Singular Formula

HDL cholesterol is integrated into Singular's personalisation engine as a cardiovascular profile adjustment parameter. When HDL falls within the low or very low range, the dosage of omega-3 (EPA+DHA) is increased. EPA and DHA contribute to the normal function of the heart (authorised health claim).

Berberine, included in the Singular formula, is a bioactive whose influence on lipid profile is documented in the scientific literature. Its effect on lipoproteins is the subject of numerous publications.

HDL is part of a set of lipid markers measured jointly by Singular: apolipoprotein B and triglycerides complete the picture. This cross-reading allows the formulation engine to fine-tune nutritional calibration based on the overall lipid profile, rather than an isolated marker.

Scientific Studies

Frequently Asked Questions