The research tracked how 40 healthy adults ages 50 and over who ate one fresh avocado a day for six months experienced a 25 percent increase in lutein levels in their eyes and significantly improved working memory and problem-solving skills.
Lutein is a type of carotenoid antioxidant or pigment—commonly found in fruits and vegetables—already widely accepted to have a role in preserving eye health and now increasingly thought to have a positive impact on brain health as well.
"The results of this study suggest that the monounsaturated fats, fibre, lutein and other bioactives make avocados particularly effective at enriching neural lutein levels, which may provide benefits for not only eye health, but for brain health," said Dr Elizabeth Johnson, lead investigator of the study from the Jean Mayer United States Department of Agriculture’s Human Nutrition Research Centre on Ageing, at Tufts University.
As the study’s participants incorporated one medium avocado into their daily diet, researchers monitored gradual growth in the amount of lutein in their eyes and progressive improvement in cognition skills as measured by tests designed to evaluate memory, processing speed and attention levels. In contrast, the control group which did not eat avocados experienced fewer improvements in cognitive health during the study period.
"The results of this new research reveal that macular pigment density more than doubled in subjects that consumed fresh avocados, compared to a supplement. Thus, a balanced diet that includes fresh avocados may be an effective strategy for cognitive health,” concluded Dr Johnson.