Avocados help lower “bad” cholesterol

Eating one avocado a day may help keep bad cholesterol at bay, according to a new study from Pennsylvania State University in Centre County and published in The Journal of Nutrition.

Bad cholesterol can refer to both oxidized low-density lipoprotein (LDL) and small, dense LDL particles, researchers said.

In a randomized, controlled feeding study, the researchers found that eating one avocado a day was associated with lower levels of LDL, specifically small, dense LDL particles, and oxidized LDL in adults with overweight or obesity.

The study found that avocados helped reduce LDL particles that had been oxidized. Similar to the way oxygen can damage food, like a cut apple turning brown, the researchers said oxidation is also bad for the human body.

While previous research demonstrated that avocados could help lower LDL cholesterol, the researchers were curious about whether avocados could also help lower oxidized LDL particles.

The researchers recruited 45 adult participants with overweight or obesity for the study. All participants followed a two-week run-in diet at the beginning of the study. This diet mimicked an average American diet and allowed all participants to begin the study on similar nutritional footing.

Next, each participant completed five weeks of three different treatment diets in a randomized order. Diets included a low-fat diet, a moderate-fat diet, and a moderate-fat diet that included one avocado a day. The moderate-fat diet without avocados were supplemented with extra healthy fats to match the amount of monounsaturated fatty acids that would be obtained from the avocados.

After five weeks on the avocado diet, participants had significantly lower levels of oxidized LDL cholesterol than before the study began or after completing the low- and moderate-fat diets. Participants also had higher levels of lutein, an antioxidant, after the avocado diet.

The researchers added that because the moderate-fat diet without avocados included the same monounsaturated fatty acids found in avocados, it is likely that the fruit has additional bioactives that contributed to the benefits of the avocado diet.

Penny Kris-Etherton, PhD, RD, lead author of the study and distinguished professor of nutrition, said in a statement that while the results of the study are promising, there is still more research to be done.

"Nutrition research on avocados is a relatively new area of study, so I think we're at the tip of the iceberg for learning about their health benefits," Kris-Etherton said. "Avocados are really high in healthy fats, carotenoids, which are important for eye health, and other nutrients. They are such a nutrient-dense package, and I think we're just beginning to learn about how they can improve health."