A daily avocado could improve the focus and attention of overweight people, a US study has found.
The finding shows how small changes in diet can benefit cognitive health. Previous research has shown that people who are overweight or obese are at a higher risk of cognitive decline in older age.
Of particular interest was a naturally occurring pigment in avocados called lutein, which is associated with cognitive benefits.
Over the course of 12 weeks, the researchers provided daily meals to 84 participants who were classed as overweight or obese. The meals were identical in calories and macronutrients, but one group’s meals included a fresh avocado, while the other group’s did not.
Before and after the study, the participants completed three cognitive tests. Two of these showed no marked difference, but the avocado-eaters performed better on a task designed to measure ‘attentional inhibition’ – the ability to stay focused on a task even when being distracted.
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“It could be that nutrients in avocados have a specific action in the brain that supports the ability to do this task in particular, or they could be more beneficial for certain cognitive abilities over others,” said Dr Naiman Khan, who led the study.
Surprisingly, however, performances in the task were not correlated with the participants’ lutein levels.
“Avocados also are high in fibre and monounsaturated fats,” said graduate student Caitlyn Edwards. “It is possible that these other nutrients may have played a role in the cognitive effects we saw.”
“Our mission is to give people options,” said Khan. “There are multiple ways people can eat to optimise brain health. What we’re learning is that avocados may be one of those fruits that may be neuroprotective in certain ways.
“This work provides some evidence behind one option people have from a plethora of healthful foods that we can consume.”
Would it be possible to live healthily on only a few types of food?
Yes, but it gets harder the fewer foods you allow. To stay healthy you need carbohydrates, fats and proteins – and not just any proteins, but a mix containing all 22 amino acids from which your own proteins are built.
You need trace elements, vitamins and minerals as well. Avocados reputedly include all these, but not in the right proportions, so you’d need to choose additional foods carefully.