Effects of one avocado a day for six months on cognitive performance in overweight adults: A randomized controlled trial

BACKGROUND: With the rising incidence of neurodegenerative diseases and aging of the global population, it is important to investigate foods that may preserve cognitive function with advancing years. Avocados are rich in fiber, carotenoids, antioxidants, polyphenols and monounsaturated fat, all of which have been associated with improved cognition. OBJECTIVE: To determine if consuming one avocado per day for 6 months has cognitive benefits in adults with central obesity, addressing cognitive health early in the aging trajectory. METHODS: This was an ancillary study of the multicenter Habitual Diet and Avocado Trial (HAT), which investigated the effect of avocado consumption on visceral adiposity. The effect of avocado consumption on cognition was assessed in participants at the Loma Linda University center. Participants with elevated waist circumference (n = 251) were randomly assigned to consume 1 avocado per day (AVO), or to avoid consuming avocados (CON) for 6 months without additional dietary guidance. Cognitive function (memory, processing speed, executive function, simple reaction time, and working memory reaction time) was measured at baseline and end of the intervention period. A series of mixed analyses of covariance was conducted to assess changes in the five cognitive scores over the 6-month intervention, group differences (AVO vs. CON), and modification of intervention effects by age. RESULTS: A total of 241 participants (69.7% female, 53.1% white, mean BMI = 33.4 ± 5.7) between the ages of 25-84 years (mean age = 49.6 ± 13.3 years) completed the trial. Working memory reaction time improved for all participants at the end of the 6-month intervention, but no significant group by time interactions were found between the AVO and CON groups in any of the cognitive domains. There were no significant two-way interactions with age by time or intervention group, and the three-way interaction was also non-significant. CONCLUSIONS: The consumption of one avocado per day without any additional lifestyle modifications for six months did not significantly alter cognitive function in adults with central obesity across all age groups. Additional work is needed to determine whether avocados, as part of dietary strategies initiated in midlife, contribute to healthy cognitive aging, particularly in normal weight and metabolically vulnerable populations.