According to Penn State researchers, bad cholesterol can refer to both oxidized low-density lipoprotein (LDL) and small, dense LDL particles. 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.
"We were able to show that when people incorporated one avocado a day into their diet, they had fewer small, dense LDL particles than before the diet," said Penny Kris-Etherton, distinguished professor of nutrition, who added that small, dense LDL particles are particularly harmful for promoting plaque build-up in the arteries. "Consequently, people should consider adding avocados to their diet in a healthy way, like on whole-wheat toast or as a veggie dip."
Specifically, 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.
"A lot of research points to oxidation being the basis for conditions like cancer and heart disease," Kris-Etherton said. "We know that when LDL particles become oxidized, that starts a chain reaction that can promote atherosclerosis, which is the build-up of plaque in the artery wall. Oxidation is not good, so if you can help protect the body through the foods that you eat, that could be very beneficial."
While previous research demonstrated that avocados could help lower LDL cholesterol, Kris-Etherton and her colleagues were curious about whether avocados could also help lower oxidized LDL particles.