Researchers followed more than 110,000 men and women for over 30 years and found evidence that eating two servings of avocado a week may help prevent heart disease.
The study also reports that that replacing half a serving of butter, cheese, bacon, or other animal products with the same amount of avocado was associated with up to a 22% lower risk of heart disease.
The findings add to evidence that avocados, which contain multiple nutrients, including fiber and unsaturated, healthy fats, have a positive impact on the heart, says Lorena S. Pacheco, PhD, one of the researchers at the Harvard T.H. Chan School of Public Health who did the study.
"For the most part, we have known that avocados are healthy, but I think this study, because of its numbers and duration, adds a little more substance to that knowledge now," she says.
Avocados are dense with nutrients. They are high in fat, but the kinds viewed as good -- monounsaturated fats and polyunsaturated fats.
Avocados also contain fiber, potassium, magnesium, and other nutrients.
To see what effect avocados might have on heart health, Pacheco and her team turned to two large, long-running studies:
All the people in the study were free of cancer, heart disease, and stroke when the studies began.
They answered questions about their diet when they started the study and then every 4 years later. The questionnaire asked how often they ate avocado and how much. One serving was half of an avocado, or a half-cup.
In the early days of one study, very few participants said they ate avocados, but that began to change over the years, as avocados got more popular.
There were 9,185 heart attacks and 5,290 strokes documented over 30 years of follow-up.
After adjusting for lifestyle and other diet factors, those who ate at least 2 servings of avocado per week had a 16% lower risk of heart disease and a 21% lower risk of coronary heart disease.
Because of the type of study this is, it "cannot prove cause and effect," Pacheco says, but the researchers did see a pattern of eating avocados reducing the risk of heart disease.
The findings are significant "because a healthy dietary pattern is the cornerstone for cardiovascular health. However, it can be difficult for many Americans to achieve and adhere to healthy eating patterns," Cheryl Anderson, PhD, a professor and dean of public health at the University of California, San Diego, said in a statement.
"We desperately need strategies to improve intake of [American Heart Association] -recommended healthy diets, such as the Mediterranean diet, that are rich in vegetables and fruits,” said Anderson, who was not involved with the study.
“Although no one food is the solution to routinely eating a healthy diet, this study is evidence that avocados have possible health benefits,” she said. “This is promising because it is a food item that is popular, accessible, desirable and easy to include in meals eaten by many Americans at home and in restaurants."