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Why are avocados heart-healthy?

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Avocados increasingly confirm their nutritional power in scientific studies of all kinds, always as one of the pieces of gear in a healthy diet. And of course, without atavisms or healings involved, as some pseudo-nutritionists preach, its role in preventing cardiovascular disease and some chronic diseases that can lead to an unhealthy lifestyle has been demonstrated. 

Avocado

A product a few years ago was only seen in gourmet greengrocers. Today it is in the humblest markets and large hypermarkets, almost always above the price of olive oil. In Mexico, they call it the “green gold”. In other places, “the fruit of life” and its producers want to classify it as a “universal fruit”. In culinary circles, they say that it has conquered the gastronomy of the four cardinal points, and in the jargon of nutritionists, it is considered a superfood.

But what about in the scenario of disease prevention and health promotion? Avocados make good crumbs with nuts and olive oil, which have similar benefits in the Mediterranean diet. Still, they have caught on in consumers’ taste before in the dietary recommendations of health centres. 

This same week, a study published in the Journal of the American Heart Association, the scientific journal of the American Heart Association (AHA), went around the world, confirming the role of avocados in reducing cardiovascular risk. Among the conclusions: eating two or more servings of avocados a week is associated with a lower risk of cardiovascular disease (CVD), as is eating avocado instead of foods with saturated fats, such as butter, cheese or processed meats.

This study supports a positive association between higher avocado consumption and fewer cardiovascular events, which has not been demonstrated in large prospective samples but in small clinical trials so far.

The research is part of two large US prospective studies that have been running for 30 years. The Nurses’ Health Study includes more than 68,000 women (ages 30 to 55), while the Harvard University Health Professionals Follow-up Study includes more than 41,000 men ages 40 to 75.

9,185 coronary heart disease events and 5,290 strokes have been documented over 30 years of follow-up. The researchers periodically evaluated the participants’ diet using food frequency questionnaires and one of their avocados. To calculate the intake, it was determined that one serving was equal to half an avocado or half a cup. 

The main findings of this research, simplifying, are:

  • Those who ate at least two servings of avocado a week had a 16% lower risk of cardiovascular disease and a 21% lower risk of coronary heart disease than those who never or rarely ate the fruit.
  • Replacing half a daily serving of margarine, butter, eggs, yoghurt, cheese, or processed meats (such as bacon) with an equal amount of avocado was associated with between 16% and 22% reduced risk of CVD episodes.
  • Substituting half a daily serving of avocado for the equivalent amount of olive oil, nuts, and other vegetable oils did not show the superiority of this fruit. Instead, the findings align with previous analyzes of foods rich in monounsaturated fatty acids (EVOO and walnuts ) with similar effects and CVD risk reductions.
  • No significant relationship was seen between the risk of cerebrovascular accidents (such as stroke ) and the amount of avocado consumed.

According to the researchers, these results are easily applicable to the care routine of health professionals, who could recommend to patients the substitution of some foods with saturated fats, such as butter, for fresh avocado. When this fruit is ripe, it is creamy and easy to spread on toast, prepare it in guacamole or even make an egg-free mayonnaise. There is a wide range of possibilities to introduce it in sandwiches and salads.

Unsaturated fats of plant origin

The main author of the study, Lorena Pacheco, a postdoctoral researcher in Nutrition at the TH Chan School of Public Health (Harvard University), explained to CuídatePlus that this work has important implications for public health “since it provides more evidence that the intake of unsaturated fats of vegetable origin can improve the quality of the diet and is an important component in the prevention of cardiovascular diseases in the general population”. She further stresses that it is the first large prospective study to “examine and generate evidence on the longitudinal association between avocado consumption and CVD events.”

Given the great impact of the study results, Pacheco warns that avocados, although beneficial, should be consumed in the context of a balanced diet because they are not a “magic bullet” in the dietary pattern. In other words, taking a lot of avocados but consuming an excess of saturated fat would counteract its effects. “Apart from being a food rich in nutrients, it is also rich in calories, so combining avocados with chips, snacks, chips or the like compromises the benefits that the fruit may bring. In most cases, when you have guacamole or similar spreads, it’s easy to overconsume them, which adds to the total calories,” he says, recommending that you always estimate portions. 

On the “secrets” of the nutritional profile that promotes the cardioprotective value of this fruit, the nutritionist lists its main favourable food compounds, which include monounsaturated and polyunsaturated fats (healthy fats), vitamins, minerals, soluble fibre, vegetable proteins, phytosterols and polyphenols. “The main monounsaturated fatty acid in avocados is oleic acid, and it is suggested that it helps reduce hypertension, inflammation and insulin sensitivity. In addition, plant sterols and soluble fibre can favourably affect lipid profiles and help lower “bad cholesterol.”

More Primary Health Benefits

On the other hand, a few months ago, Nutrients (2021) published the first comprehensive review on the different health benefits of consuming fresh avocados was published in Nutrients (2021), covering 19 clinical trials, 5 observational studies and analyses of biological mechanisms.   

The review’s authors do research for the consulting firm Nutrition Science Solutions and the Avocado Nutrition Center (United States), studying the Hass variety, the world market leader. These avocados are characterized by dark green wrinkled skin, which turns almost black or purplish when ripe. In Spain, they are also the most demanded among the ten varieties grown.

When grouping the results of the different studies, four primary effects of avocado on health have been confirmed:

  • Reduces the risk of cardiovascular disease in healthy overweight or obese adults with dyslipidemia by (lowering non-HDL cholesterol, triglycerides, LDL oxidation, and small atherogenic LDL particles) and promoting postprandial (after eating) vascular endothelial health by improving peripheral blood flow.
  • Reduces the risk of overweight or obesity by promoting weight loss and visceral adipose tissue in women.
  • Improves cognitive function in older adults of normal weight and overweight or obese young or middle-aged adults, especially the executive function of the frontal cortex.
  • Promotes a healthier colonic microbiota in overweight or obese adults in overweight or obese adults by improving the microflora and faecal metabolites.

“The health effects of Hass avocado are best demonstrated when consumed in a healthy diet plan such as the Mediterranean diet,” they conclude in this study, coinciding with the previously mentioned Harvard study.

The unique combination of nutrients

Furthermore, the same researchers have identified a unique combination of four nutritional characteristics of Hass avocado that would support these health benefits. 

  • A ratio of 6 to 1 of unsaturated fats (rich in oleic acid) and a percentage of saturated fats similar to olive oil.
  • It is a source of viscous fibre and a multifunctional prebiotic.
  • Its energy density is relatively low, 1.6 kcal/g. 79 per cent of the weight of those types of avocados consists of water and fibre.)
  • The emulsion of oleic acid and water increases the absorption of carotenoids from low-fat fruits and vegetables when consumed with avocados. This is the case with vegetable-based salads or sauces.
  • They are also rich in micronutrients and polyphenols that add secondary health and wellness benefits. . One of its advantages is that they hardly contain salt or sugar.

Nutritional composition 

A serving of fresh Hass avocado (50 g or 1/3 of a medium piece) contains 80 kcal, 3.4 g fibre, 44.5 μg folate, 0.73 mg pantothenic acid, 85 μg copper, 10, 5 μg of vitamin K, 254 mg of potassium and 4 mg of sodium. A serving of Hass avocado contains:

  • No cholesterol.
  • 1 g of saturated fatty acids.
  • 4.9 g of monounsaturated fatty acids.
  • 1 g of polyunsaturated fatty acids.
  • 4.5 g of oleic, the predominant fatty acid.

According to some comparative studies, other varieties of avocados differ in their nutritional profile.