Written by Jessica Patella, ND. Those with the highest consumption of green leafy vegetables experienced slower cognitive decline, perhaps due to the neuroprotective actions of lutein, folate, β-carotene, and phylloquinone.
According to the World Health Organization an estimated 47 million people worldwide are living with dementia and that is expected to increase to 75 million by 2030, with the aging Baby Boomer population 1. The cost of dementia is not just for the individual but also to families that care for those with dementia, with a staggering cost of $818 billion (USD) per year worldwide 1. For this reason dementia is a public health priority and recent research has found consuming green leafy vegetables daily can slow cognitive decline with aging 2.
The study included participants from the Rush Memory and Aging Project (MAP; a study of 40 retirement communities, senior public housing and senior centers in the Chicago area). At onset of the longitudinal study, participants were free of dementia. Participants included in this analysis completed a food frequency questionnaire (FFQ; 144 food items) at each annual clinical evaluation. The three green leafy vegetable items on the FFQ included: spinach (1/2 cup cooked), kale/collards/greens (1/2 cup cooked) and lettuce salad (1 cup raw). The annual visits also included cognitive testing by trained and certified technicians (episodic memory, working memory, semantic memory, visuospatial ability and perceptual speed) 2.
A total of 960 participants from the MAP study were included (average age 81, 74% female, average education 14.9 years). The average time of follow-up was 4.7 years (range 2-10 years). The intake of green leafy vegetables ranged from 0.09 to 1.3 servings per day (lowest quintile to highest quintile). Those with the highest intake of green leafy vegetables (1.3 servings per day) had slower cognitive decline and were more likely to be higher educated, male, participate more frequently in cognitive and physical activities and to have fewer cardiovascular and depressive symptoms 2. Consumption of green leafy vegetables correlated with food intakes of nitrate (r=0.78), lutein and phylloquinone (r=0.67), and beta-carotene (r=0.60) and moderately with folate (r=0.47), anti-oxidants and nutrients that may explain the improvement seen in brain functioning 2.
When comparing those with the highest intake of green leafy vegetables (1.3 servings/day) and cognitive decline with those in the lowest (0.09 servings/day), the difference was equivalent to about 11 years younger 2. These results are supported by two other studies that found green leafy vegetables, including spinach, kale, collards and lettuce had the strongest correlation with slowing cognitive decline 2-4.
In conclusion, eating green leafy vegetables was correlated with slower cognitive decline in older age. A limitation of this study is that 95% of participants were white, so it might not be possible to infer the results to other populations. Researchers stated that adding a daily serving of green leafy vegetables is a simple way to improve brain health 2.
Source: Morris, Martha Clare, Yamin Wang, Lisa L. Barnes, David A. Bennett, Bess Dawson-Hughes, and Sarah L. Booth. “Nutrients and bioactives in green leafy vegetables and cognitive decline: Prospective study.” Neurology 90, no. 3 (2018): e214-e222.
© 2017 American Academy of Neurology
Posted on April 23, 2019.
References:
- WHO. 10 Facts on Dementia. 2017; Summary of facts about dementia. Available at: https://www.who.int/features/factfiles/dementia/en/. Accessed April 18, 2019.
- Morris MC, Wang Y, Barnes LL, Bennett DA, Dawson-Hughes B, Booth SL. Nutrients and bioactives in green leafy vegetables and cognitive decline: Prospective study. Neurology. 2018;90(3):e214-e222.
- Kang JH, Ascherio A, Grodstein F. Fruit and vegetable consumption and cognitive decline in aging women. Ann Neurol. 2005;57(5):713-720.
- Morris MC, Evans DA, Tangney CC, Bienias JL, Wilson RS. Associations of vegetable and fruit consumption with age-related cognitive change. Neurology. 2006;67(8):1370-1376.
