Avocado consumption improves cognitive function in overweight, obesity patients

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A diet including daily avocado consumption improves the ability to focus attention in adults whose measurements of height and weight are categorized as overweight or obese, according to new research from the University of Illinois at Urbana-Champaign published in the International Journal of Psychophysiology.

In a randomized controlled trial, researchers provided 12 weeks of daily meals to 84 adults with overweight or obesity. The meals were identical in calories and macronutrients, but one group's meals included a fresh avocado every day, while the control group had no avocado in their meals.

At the beginning and end of the study, the participants completed three cognitive tests to measure attention and inhibition. In addition, the researchers measured lutein levels in the participants' serum and in their retinas, which is associated with the lutein concentration in the brain. Avocados are high in lutein, the researchers said.

The Hass Avocado Board and the U.S. Department of Agriculture's National Institute of Food and Agriculture supported the study.

The researchers found that participants whose diets included avocados improved their performance on one of the cognitive tests, called the Flanker task, which measures attentional inhibition, the ability to maintain focus on the task at hand even in the face of distraction. However, there was no difference in the other two cognitive tests.

Further, while the participants who ate avocados had higher levels of lutein at the end of the study, the changes in lutein levels were not correlated with their cognitive changes.

Although this study focused on avocados, other dietary sources of lutein, fiber, and unsaturated fats such as green leafy vegetables or eggs also have potential cognitive and health benefits. The researchers say their study shows that small dietary changes can have measurable impacts on cognitive performance, even when other health behaviors remain the same.

“There are multiple ways people can eat to optimize brain health,” said Naiman Khan, PhD, lead author and assistant professor of kinesiology and community health. “This work provides some evidence behind one option people have from a plethora of healthful foods that we can consume.”