The creamy, pale green flesh of an avocado is full of nutrients closely tied to heart health. Now, a long-term study finds that eating at least two servings of this popular fruit per week is linked to a lower risk of cardiovascular disease.
Study co-author Dr. Frank Hu, the Frederick J. Stare Professor of Nutrition and Epidemiology at the Harvard T.H. Chan School of Public Health (HSPH), puts this finding in perspective. "This study adds to the evidence to support the benefits of healthy fat sources like avocados to help prevent cardiovascular disease," he says. A key take-home message is to substitute avocados for less-healthy foods such as butter, cheese, and processed meats, he adds.
Who was in the study?
The study included more than 110,000 people involved in two long-running Harvard studies: the Nurses’ Health Study and the Health Professionals Follow-up study. Most of the participants were white; they ranged in age from 30 to 75 and were free of heart disease and cancer when the study began.
Researchers assessed the participants’ diets via questionnaires given at the start of the study and then every four years. One question asked how much and how often people ate avocado. A serving was considered a half an avocado or one-half cup, cubed.
What were the findings?
During the 30-year follow-up, researchers documented 9,185 heart attacks and 5,290 strokes among the participants. Compared with people who never or rarely ate avocados, those who ate at least two servings each week had a 16% lower risk of cardiovascular disease and a 21% lower risk of experiencing a heart attack or related problem due to coronary artery disease. (Coronary artery disease refers to a narrowing or blockage in the blood vessels that supply the heart; it’s the most common type of cardiovascular disease.)
What makes avocados a heart-healthy choice?
Hass avocados, which have dark green, nubbly skin, are the most popular variety in the United States. They’re abundant in healthy fats, fiber, and several micronutrients associated with cardiovascular health:
- Oleic acid. This monounsaturated fat is also plentiful in olives. Half an avocado has around 6.5 grams of oleic acid, or about the same amount found in a tablespoon of olive oil. Research shows that replacing foods high in saturated fat (such as butter, cheese, and meat) with those rich in unsaturated fats (such as avocados, nuts, and seeds) helps lower blood levels of harmful LDL cholesterol, a key culprit in coronary artery disease.
- Fiber. One serving of avocado provides up to 20% of the daily recommended dietary intake of fiber, a nutrient that’s often lacking in the typical American diet. Fiber-rich diets may lower heart disease risk as much as 30%, probably because fiber helps lower not only cholesterol, but also blood pressure and body weight.
- Vitamins, minerals, and more. Half an avocado provides 15% of daily recommended intake of folate (vitamin B9), 10% of potassium, and 5% of magnesium, as well as various plant-based compounds called phytochemicals. All of these nutrients — along with oleic acid and fiber — have been independently linked to better heart health.
The good news is that there are so many delicious ways to add avocado to your meals, says Dr. Hu. "I make avocado toast for breakfast, use avocado as a spread for sandwiches, and add them to salads," says Dr. Hu. Some people add avocado to their smoothies — and of course, there’s always guacamole (try this recipe from the HSPH’s Nutrition Source).
About the Author
Julie Corliss, Executive Editor, Harvard Heart Letter
Julie Corliss is executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She is co-author of Break Through Your Set Point: How to Finally Lose the Weight You Want and Keep it Off. Julie earned a BA in biology from Oberlin College and a master’s certificate in science communication from the University of California at Santa Cruz. View all posts by Julie Corliss