The randomized, controlled study looked at 45 adults, who followed a two-week diet at the beginning of the study that mimicked an average American diet and put all participants on a similar nutritional level. They then completed five weeks of three different treatment diets in a randomized order: a low-fat diet, a moderate-fat diet, and a moderate-fat diet that included one avocado a day.
Those on the avocado diet had significantly lower levels of oxidized LDL cholesterol than before the study began or after completing the low- and moderate-fat diets. They also had higher levels of the antioxidant lutein after the avocado diet.
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In a press release, Penny Kris-Etherton, Professor of Nutrition, said, “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. Consequently, people should consider adding avocados to their diet in a healthy way, like on whole-wheat toast or as a veggie dip.”She added that it’s particularly notable that avocados could help lower oxidized LDL particles: “A lot of research points to oxidation being the basis for conditions like cancer and heart disease. 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 release noted that the moderate-fat diet without the avocado included the same monounsaturated fatty acids found in avocados, making it likely that avocados have additional bioactives contributing to the benefits found.
All of that said, Kris-Etherton adds that there is 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. 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.”
