Forget the apples — new research suggests eating one avocado a day may help keep "bad cholesterol" at bay. According to the researchers, bad cholesterol can refer to both oxidized low-density lipoprotein (LDL) and small, dense LDL particles. In a randomized controlled nutritional study, the researchers found that eating one avocado per day was associated with lower levels of LDL (particularly small, dense LDL particles) and oxidized LDL in overweight or obese adults.
"We were able to show that when people included one avocado a day in their diet, they had fewer small, dense LDL particles than before the diet," said the researcher. Those small, dense LDL particles are particularly harmful for promoting plaque buildup in the arteries. “That's why people should consider adding avocados to their diet in a healthy way, such as on whole wheat toast or as a vegetarian dip.”
More specifically, the study found that avocados helped reduce LDL particles that had become oxidized. Similar to the way oxygen can damage food — like a sliced apple turning brown — the researchers said oxidation is also bad for the human body.
“A lot of research indicates that oxidation is the basis for conditions such as cancer and heart disease.” “We know that when LDL particles are oxidized, it sets off a chain reaction that can promote atherosclerosis, which is the buildup of plaque in the artery wall. Oxidation is not good, so if you can help protect the body through the food you eat, it can be very beneficial.”
The researchers recruited 45 overweight or obese adult participants for the study. All participants followed a two-week "walk-in" diet at the start of the study. This diet mimicked an average American diet and allowed all participants to start the study on a similar nutritional basis.
Then, 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 per day. The moderate-fat diet without avocados was supplemented with extra healthy fats corresponding to 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-fat and moderate diets. Participants also had higher levels of lutein, an antioxidant, after the avocado diet.
The researcher said there was specifically a reduction in small, dense LDL cholesterol particles that were oxidized.
