Eating one avocado a week cuts the risk of heart disease by a fifth, according to Harvard scientists.

       Two or more servings weekly - equivalent to one whole avocado - appears to slash the risk of coronary heart disease by 21 per cent, compared with people who do not eat avocados.

       Avocados contain high levels of fibre, healthy fats and other key nutrients, including magnesium and vitamins C, E, and K. They have become increasingly popular in recent years, often served on top of sourdough bread alongside poached eggs.

       Previous studies have shown that eating avocado has various health benefits, including reducing cholesterol, body weight, BMI and waist size.

       Diet swaps recommended

       In the new study, more than 100,000 people were followed for several years to see how their avocado consumption impacted on long-term health conditions.

       They found that as well as a 21 per cent reduction in the risk of coronary heart disease, there was a 16 per cent drop in the likelihood of developing any other form of cardiovascular disease.

       Dr Lorena Pacheco, lead author of the study from the Harvard T H Chan School of Public Health in Boston, said: “Our study provides further evidence that the intake of plant-sourced unsaturated fats can improve diet quality and is an important component in cardiovascular disease prevention.

       “These are particularly notable findings, since the consumption of avocados has risen steeply in the US in the last 20 years, according to data from the US Department of Agriculture.”

       More than seven million people in the UK have cardiovascular disease and more than two million suffer from coronary heart disease.

       The findings, published in the Journal of the American Heart Association, asked people about their diets with food frequency questionnaires at the start of the study, repeated every four years.

       During a 30-year follow-up, more than 14,000 cases of heart-related issues were recorded, including 9,185 heart attacks and 5,290 strokes.

       The research also found that replacing half a serving daily of margarine, butter, egg, yoghurt, cheese or processed meats such as bacon with the same amount of avocado led to a drop in the risk of cardiovascular disease events of about a fifth.

       Recommending these swaps, Dr Pacheco said, is something doctors and nutritionists can now be comfortable in recommending to patients as a result of this study’s findings.

       However, substituting half a serving a day of avocado for the equivalent amount of olive oil, nuts and other plant oils did not offer additional benefit. No links were found between eating avocado and the risk of stroke.

       Dr Cheryl Anderson, chairman of the American Heart Association (AHA) Council on Epidemiology and Prevention, said: “These findings are significant because a healthy dietary pattern is the cornerstone for cardiovascular health.

       “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 … at home and in restaurants.”