Consumption of Potatoes, Avocados and Chickpeas and Cognitive Function in Older Adults

Overview

Cognitive impairment is also a major risk factor for development of dementia later in life. Findings from the investigators studies suggest that the carotenoids, lutein and zeaxanthin may be important in cognitive function in the elderly. Avocados are a source of these carotenoids. The investigators study evaluates long-term avocado intervention as a treatment strategy for age-related cognitive impairment which could possibly prevent the onset of dementia. The investigators have also shown that lutein supplementation significantly improved verbal fluency scores in healthy older women. Based on these findings, the next logical step will be to investigate the ability of lutein and zeaxanthin contained in avocados to influence cognitive function in older adults. The investigators hypothesize that there will be a significant increase in cognitive function measures in older adults provided with meals containing 1 avocado/day at the end of 6 months, while no significant improvements will be observed in older adults given daily meals containing chickpeas and/or potatoes. The proposed study is designed as a randomized, placebo controlled trial that tests the effects of 6 month supplementation with 1 avocado/day on cognitive function in older adults. Secondary analyses will determine whether baseline macular pigment (lutein in retina which canbe measured non invasivley) density predicts relative effectiveness of the intervention on cognitive function. Secondary outcomes include plasma biomarkers of oxidative stress and inflammation.

The study is designed as a placebo controlled trial that tests the effects of 6 month supplementation with daily meals containing 1 avocado or isocaloric amounts of chickpeas and/or potatoes on cognitive function in older adults. Subjects will be randomly assigned to one of the two groups. Secondary analyses will determine whether baseline macular pigment density (a non invasive measure of lutein and zeaxanthin in neural tissue) predicts relative effectiveness of the intervention on cognitive function. Secondary outcomes include plasma biomarkers of oxidative stress and inflammation. Participants will be recruited from community-dwelling men and women aged \>50 yr, and potential participants will be screened to meet cognitive and functional criteria. Participants will be pre-screened by telephone; those who appear to meet criteria will undergo further screening. The study will include baseline (0 month), 3 and 6 month visits for study procedures, and monthly telephone calls. Given that there is a visible difference between the two interventions, a blinded study is not possible.