What happened to the brains of people who ate an avocado every day for half a year?

Avocados are one of those rare foods that manage to enjoy an almost perfect image. They look good on toast, blend excellently into salads, add a creamy and rich texture to any dish, and have been considered for years one of the biggest stars of a healthy diet. Therefore, it is not surprising at all that many researchers have also tried to examine whether all this goodness can affect not only the heart or the digestive system, but also the brain.

But here comes an unexpected result: A new study found that eating one avocado every day for half a year did not significantly improve cognitive function in participants. Meaning, at least in this study, the avocado did not make the participants sharper, faster, or better in memory and thinking tests, unlike what the researchers expected to discover at the end of the experiment.

The study, recently published in The Journal of Nutrition, Health and Aging, was a sub-study within a larger trial called HAT - Habitual Diet and Avocado Trial. It was conducted among 251 participants with obesity, who were randomly divided into two groups: One group was asked to eat one avocado a day for six months, while the second group was asked to avoid avocados.

The researchers did not give the participants additional guidelines for lifestyle or dietary changes and tested their core cognitive functions such as memory, information processing speed, executive function, simple reaction time, and working memory reaction time. Of the participants, 241 completed the study, about 70 percent of whom were women, with an average age of about 50 and an average BMI of 33.

Not every healthy food improves brain function

At the end of the six months, the researchers found that working memory reaction time improved among all participants, but there was no significant difference between those who ate avocados every day and those who avoided them. Even when the researchers checked whether the age of the participants changed the picture, no significant interaction was found between avocado consumption and performance. Their conclusion was that eating an avocado every day, without additional lifestyle changes, did not lead to a significant improvement in cognitive function.

But the interesting part of the story is that the researchers did not just randomly choose to deeply examine the effect of avocados specifically. After all, it is known that avocados contain fiber, antioxidants, polyphenols, and good fats - components that have been linked in previous studies to improved cognitive function. Therefore, the hypothesis was logical: If such a food is integrated into the daily menu, perhaps a measurable change in memory or general functioning could be identified. In practice, at least in this experiment as mentioned, this hypothesis received no scientific backing.

It is important to note that this is not the first study to seek to examine the link between avocados and brain function. A smaller study published in 2017 in the journal Nutrients followed 40 healthy adults aged 50 and older for six months. Participants in one group ate one avocado a day, while the control group ate one potato or a cup of chickpeas. In that study, an improvement was observed in certain measures of attention and problem solving, but it is important to understand that this is a small study with limited findings.

So are avocados still beneficial for health?

The short answer is yes, we simply do not need to attribute superfood status to it. The current study also does not suggest that avocados are harmful or worthless, but only that eating them daily was not enough to improve cognitive measures over six months, at least in the population tested. This is an important distinction, because a food can be healthy without producing a dramatic change in cognitive tests.

Avocados have recognized nutritional benefits. Previous studies have linked avocado consumption to improved diet quality and certain measures of heart health, among other things through a beneficial effect on the blood lipid profile. The 2017 study even found that avocado consumption led to an increase in the level of lutein, a component linked to eye and brain health, although not every study manages to translate this change into a measurable and clear cognitive improvement.

The practical implication is that avocados can be an excellent part of a balanced diet, but they are not supposed to carry all our expectations for a rapid improvement in the health of the brain and the rest of the body. If one wants to maintain optimal cognitive function over time, it is important to also look at other aspects of health that we all already know are important: Physical activity, good sleep, blood sugar and blood pressure balance, a varied diet, social connections, and mental challenges. Avocado on toast can certainly be integrated into this mix, but it will not do the job alone.