A Plant-Based Diet In Your 40s May Slow Cognitive Decline, Study Finds

If you’ve hit your 40s and want to protect your cognitive abilities, new research has shown that following a diet rich in plants can help.

A recent study led by the NYU Grossman School of Medicine indicates that women who adopted the Dietary Approaches to Stop Hypertension (DASH) during their middle years were approximately 17 percent less likely to experience cognitive decline in later life. 

This is particularly significant for women, who constitute more than two-thirds of Alzheimer’s disease diagnoses. The study is published in the scientific journal Alzheimer’s & Dementia and has potential implications for the roughly 6.5 million Americans over 65 diagnosed with Alzheimer’s as of 2022—a figure expected to more than double by 2060.

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The DASH diet, which prioritizes the consumption of plant foods, focuses on a high intake of foods rich in potassium, calcium, and magnesium while minimizing saturated fats, cholesterol, sodium, and sugar. 

“Subjective complaints about daily cognitive performance are early predictors of more serious neurocognitive disorders such as Alzheimer’s,” Yu Chen, PhD, MPH, the senior author of the study, said in a statement. 

“With more than 30 years follow-up, we found that the stronger the adherence to a DASH diet in midlife, the less likely women are to report cognitive issues much later in life,” Chen said. 

Plant-forward DASH diet slows cognitive decline

The research team here analyzed data from 5,116 women out of over 14,000 enrolled in the NYU Women’s Health Study. They examined dietary patterns through questionnaires filled out between 1985 and 1991 when the average age of participants was 49. 

The women were subsequently followed for more than 30 years and were asked to report any cognitive issues. Self-reported cognitive complaints were evaluated using six validated questions indicative of mild cognitive impairment, a precursor to dementia. 

“Our data suggest that it is important to start a healthy diet in midlife to prevent cognitive impairment in older age,” Yixiao Song, a lead author of the study, said in a statement.

One-third of the women reported multiple cognitive complaints, but those who closely followed the DASH diet had a 17 percent lower likelihood of reporting multiple cognitive issues.

“Following the DASH diet may not only prevent high blood pressure but also cognitive issues,” Fen Wu, PhD, a senior associate research scientist and who co-led the study, said in a statement. 

While this study can be used to inform the role of diet in brain health, the researchers highlighted the need for further research across multiple racial and ethnic groups to validate these findings.

Role of fruits and vegetables in brain health

Additional research from the Virginia Tech Carilion School of Medicine suggests that a diet rich in colorful fruits and vegetables may reduce the risk of developing cognitive disorders such as dementia and Alzheimer’s disease. 

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Published earlier this year in the scientific journal Alzheimer’s Disease, this study found that Alzheimer’s patients had half the brain levels of dietary antioxidants such as lutein, zeaxanthin, and vitamin E compared to those without the disease.

“This study, for the first time, demonstrates deficits in important dietary antioxidants in Alzheimer’s brains,” C. Kathleen Dorey, a professor at the medical school, said in a statement. 

“These results are consistent with large population studies that found risk for Alzheimer’s disease was significantly lower in those who ate diets rich in carotenoids, or had high levels of lutein and zeaxanthin in their blood, or accumulated in their retina as macular pigment,” Dorey said.

The findings are further supported by the Rush University Memory and Aging Project (RUMAP)—which has observed 1,000 Chicagoans for more than a decade. Notably, RUMAP found that people who consumed the highest amount of carotenoids or lutein/zeaxanthin during the project period had a 50-percent lower risk for Alzheimer’s disease.  

Plant-forward diets for cognitive health at any age

Similar to the DASH diet, the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND diet) has been researched for its cognitive benefits. 

A study published earlier this year and led by Shelby Keye, PhD, at the University of Illinois Urbana-Champaign, found that the MIND diet was positively linked with children’s performance on tasks assessing attentional inhibition. 

“We assessed how adherence to these diets was associated with children’s attentional inhibition—the ability to resist distracting stimuli—and found that only the MIND diet was positively linked with children’s performance on a task assessing attentional inhibition,” Keye said in a statement. 

Both the DASH and MIND diets are plant-forward and are associated with cognitive benefits, albeit at different life stages. 

While the NYU study’s researchers emphasized that starting a healthy diet in midlife is crucial to prevent cognitive impairment in older age, this study indicates that earlier dietary interventions can have lasting cognitive benefits. 

Conversely, a study published last year in JAMA Neurology indicated that diets high in ultra-processed foods, including processed meats, are associated with faster rates of cognitive decline. Participants whose daily diet consisted of more than 19.9 percent ultra-processed foods experienced a 28 percent faster rate of cognitive decline. 

Taken together, these studies reinforce the importance of plant-based foods, particularly those rich in carotenoids, for maintaining cognitive health at all stages of life.