The findings add to evidence from other studies that has shown that avocados — which contain multiple nutrients, including fiber and unsaturated, healthy fats — have a positive impact on cardiovascular risk factors, first author Lorena S. Pacheco, PhD, a postdoctoral research fellow at the Harvard T.H. Chan School of Public Health, Boston, told theheart.org | Medscape Cardiology.

"This research complements and expands on the current literature that we have on unsaturated fats and reduced risk of cardiovascular disease, and also underscores how bad saturated fats, like butter, cheese, and processed meats, are for the heart," Pacheco said.

"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," Pacheco said.

The findings were published online March 30 in the Journal of the American Heart Association.

Avocados are dense with nutrients. They are high in fat, but in monounsaturated fats (MUFAs) and polyunsaturated fats (PUFAs), which are viewed as good.

A medium-sized (136 g) Haas avocado, which is the most commonly consumed avocado in the United States, contains roughly 13 g of oleic acid. Avocados also contain dietary fiber, potassium, magnesium, phytonutrients, and bioactive compounds.

To see the effect avocados can have on cardiovascular health, Pacheco and her team turned to two large, long-running cohort studies: the Nurses' Health Study (NHS), which began in the early 1970s with 68,786 women 30 to 55 years of age; and the Health Professionals Follow-up Study (HPFS), which ran from 1986 to 2016 and followed 41,701 men 40 to 75 years of age.

All were free of cancer, coronary heart disease, and stroke at study entry.

Participants completed a validated food frequency questionnaire at baseline and every 4 years thereafter. The questionnaire asked about the amount and frequency of avocado consumed. One serving equalled half an avocado, or half a cup.

In the early days of the NHS, very few participants said they ate avocados, but that began to change over the years, as the popularity of avocados grew.

"The NHS cohort was recruited back in the late '70s and the health professionals cohort did not start until the mid 1980s, when avocado consumption was really low," Pacheco said.

"What is beautiful about these cohorts is we are able to ask participants questions and then save the answers that they give us throughout the years to answer questions that might arise whenever the question is right. So it just depends on when you accrue enough data to ask those questions about potential cardiovascular benefit with avocados," she said.

There were 9185 coronary heart disease events and 5290 strokes documented over 30 years of follow-up.

After adjustment for lifestyle and other dietary factors, those with a higher avocado intake — at least two servings per week — had a 16% lower risk for CVD (pooled hazard ratio [HR], 0.84; 95% CI, 0.75 - 0.95) and a 21% lower risk for coronary heart disease (pooled HR, 0.79; 95% CI, 0.68 - 0.91).

No significant associations were seen for stroke, but this is because the study did not have sufficient numbers, Pacheco explained.

A statistical model also determined that replacing half a serving daily of margarine, butter, egg, yogurt, cheese, or processed meats, such as bacon, with the same amount of avocado was associated with a 16% to 22% lower risk for CVD events.

"I want to emphasize that the study is an epidemiological observational study and cannot prove cause and effect," Pacheco said.

"It's not a clinical trial — it's based on observational epidemiology — but we saw patterns in the model: avocado consumption and substituting avocado for other unhealthy fats reduced the risk of having a cardiovascular event or coronary heart disease," she said.

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, professor and dean of the Herbert Wertheim School of Public Health and Human Longevity Science at the University of California, San Diego, who is chair of the AHA's Council on Epidemiology and Prevention, said in a statement.

"We desperately need strategies to improve intake of AHA-recommended healthy diets, such as the Mediterranean diet, that are rich in vegetables and fruits. Although no one food is the solution to routinely eating a healthy diet, this study is evidence that avocados have possible health benefits. 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," said Anderson, who was not part of the study.

Pacheco and Anderson report no relevant financial relationships.

J Am Heart Assoc. Published online March 30, 2022. Abstract

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