Summary: A new study from researchers at Rush University indicates that eating one serving of leafy green vegetables daily may help preserve memory and thinking skills in older adults.
Source: Rush University Medical Center
Eating one serving of leafy greens daily may slow cognitive decline in older adults, a Rush University study suggests
While some decline in cognitive ability is expected with age, researchers at Rush University Medical Center in Chicago report that consuming at least one serving of green, leafy vegetables each day was associated with slower loss of memory and thinking skills in older adults. The study’s findings were published in the December issue of the journal Neurology.
“Adding a daily serving of green leafy vegetables to your diet may be a simple way to help promote brain health,” said study author Martha Clare Morris, ScD, a nutritional epidemiologist at Rush. She noted the growing percentage of people living with dementia among the oldest age groups and emphasized the urgent need for effective prevention strategies.
The researchers found that people who regularly ate leafy greens experienced a slower rate of decline on standardized cognitive tests compared with people who ate little or no leafy greens. After adjusting for multiple lifestyle and health factors, the cognitive performance of those who ate at least one serving per day resembled that of individuals about 11 years younger, on average.
Study design: 960 older adults completed dietary questionnaires and regular cognitive testing
The analysis used participants already enrolled in the ongoing Rush Memory and Aging Project, which began in 1997 and focuses on older adults living in retirement communities and senior housing in the Chicago area. Beginning in 2004, researchers added a food frequency questionnaire; of the participants who completed this survey between 2004 and February 2013, 960 had at least two annual cognitive assessments and were included in the cognitive change analysis.
At the start of the study period analyzed, these 960 participants had an average age of 81 and did not have dementia. They underwent annual tests of memory and thinking for an average follow-up of 4.7 years. The food frequency questionnaire asked how often participants consumed half-cup servings of spinach or kale/collards/greens and one-cup servings of lettuce or salad, allowing researchers to estimate intake of green, leafy vegetables.
Participants were grouped into five categories according to leafy-green intake. On average, those in the highest intake group consumed about 1.3 servings per day, while those in the lowest group consumed about 0.1 servings per day.
Across all participants, scores on the cognitive tests declined at a rate of 0.08 standardized units per year. Over ten years of follow-up, the decline rate among the highest leafy-green consumers was slower by 0.05 standardized units per year compared with the lowest consumers. According to the study authors, that difference corresponds to an average cognitive advantage equivalent to being roughly 11 years younger.
Findings persisted after accounting for other factors
The association between leafy-green consumption and slower cognitive decline remained after the researchers adjusted for multiple other factors known to influence brain health, including seafood and alcohol intake, smoking, hypertension, obesity, education level, and levels of physical and cognitive activity.
“The study results do not prove that eating green, leafy vegetables slows brain aging, but they do show a clear association,” Morris explained. The observational design means the study cannot definitively rule out other explanations for the link between diet and cognitive outcomes.
The researchers also noted limitations in the study population. Most participants were older adults and predominantly white, so the findings may not apply to younger people or to more diverse racial and ethnic groups. The authors call for additional studies in different populations and randomized controlled trials to determine whether increasing leafy-green consumption can directly reduce the risk or rate of cognitive decline.
Funding: The study was supported by the National Institutes of Health and the USDA Agricultural Research Service.
Source credit: Rush University Medical Center. The study results were published in the medical journal Neurology.
This rewritten summary preserves the study’s reported findings and limitations. It does not add new data or claims beyond those presented by the research team and the original institutional release.