Low-density lipoproteins (LDL) are formed in the liver and transport lipid molecules to cells. Often referred to as the “bad cholesterol,” LDL can drive cardiovascular disease if it becomes oxidized within the walls of arteries. LDL particles exist in different sizes, ranging from large, “fluffy” molecules to small, dense molecules. Scientific evidence suggests that small, dense LDL particles are more susceptible to oxidative modification. Findings from a new study suggest that diets that include avocados may help reduce LDL oxidation.

The randomized, controlled trial involved 45 men and women between the ages of 21 and 70 years. The participants, who were overweight or obese and had elevated LDL cholesterol levels, followed three different diets for a period of five weeks each: a low-fat diet, a medium-fat diet with avocado, and a medium-fat diet with oleic acids (found in olive and canola oils).

Avocados are rich sources of monounsaturated fatty acids. They also contain polyphenols and lutein, a carotenoid compound that quenches and scavenges reactive oxygen species.

After five weeks on the diet with avocado, the participants' levels of oxidized LDL cholesterol (especially the small, dense LDL cholesterol particles) were lower than their baseline levels or after completing the low- or moderate-fat diets. Concentrations of large, fluffy LDL particles were unchanged. Participants also had higher levels of lutein. These findings suggest that consuming avocados as part of an overall heart-healthy diet may reduce the risk of developing cardiovascular disease.

• Link to full study.