Doctors are not shy about prescribing stain drugs to lower cholesterol but patients wary of the side effects should look to increase their intake of avocados instead. This is because researchers at Penn State University discovered eating an avocado a day is an effective way to lower “bad” cholesterol.
Low-density lipoprotein (LDL) is considered “bad” cholesterol when it is in an oxidized form or in small, dense particles, which can promote plaque build-up in arteries. Scientists at Penn State conducted a randomized, controlled study and found daily avocado intake was associated with lower levels of small, dense LDL particles and oxidized LDL.
"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 distinguished professor of nutrition from Penn State Penny Kris-Etherton. "Consequently, people should consider adding avocados to their diet in a healthy way, like on whole-wheat toast or as a veggie dip."
The Penn State team was aware of previous research that linked avocados with lower LDL cholesterol and wanted to see if it had any effect on oxidized LDL particles.
"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."
The trial included 45 overweight and obese adults who followed a similar diet for two weeks as a lead up to ensure all participants started from a similar nutritional foundation. They then rotated through three different diets (low-fat, moderate-fat and moderate-fat with one avocado) five weeks at a time.
After five weeks on the moderate-fat diet with avocado, study participants had significantly lower levels of oxidized LDL cholesterol than prior to the study or after each of the other two diets. They also had higher levels of the antioxidant lutein in their system.
"When you think about bad cholesterol, it comes packaged in LDL particles, which vary in size but small, dense LDL is particularly bad," Kris-Etherton said. "A key finding was that people on the avocado diet had fewer oxidized LDL particles. They also had more lutein, which may be the bioactive that's protecting the LDL from being oxidized."
The results of the study were published in the Journal of Nutrition. Kris-Etherton said she was encouraged by what she found during her research but there is more work 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."