Cognitive impairment and dementia remain significant concerns for the aging population, with health disparities continuing to affect accurate diagnosis and outcomes in Black communities. In fact, Black patients are more likely to be misdiagnosed or inconsistently diagnosed with mild cognitive impairment (MCI), in part due to differences in assessment methods and structural inequities in care.
A new study published in JAMA Neurology adds another layer to the conversation, examining how specific dietary patterns could influence cognitive health and potentially slow age-related decline in older adults.
The Role of Diet in Cognitive Health
Growing evidence suggests that diet plays an important role in brain function. Dietary patterns that reduce inflammation and support cardiovascular function are increasingly linked to better cognitive outcomes over time.
In the large-scale study, the researchers assessed whether adherence to several well-known health dietary patterns was associated with slower cognitive decline in middle-aged and older adults.
What the Study Found
The researchers found that a specific healthy diet is positively associated with cognitive health.
In the cohort study, six dietary patterns were compared:
- DASH (Dietary Approaches to Stop Hypertension) diet
- Alternative Healthy Eating Index 2010
- Planetary Health Diet Index
- Healthful Plant-Based Diet Index
The DASH diet had the strongest correlation with slow cognitive decline, or SCD. The second top-performing diet was the Healthful Plant-Based Diet Index.
Researchers performed a systematic evaluation of 159,347 nurses and health professionals from three studies:
- Nurses’ Health Study (NHS, 1986-2014)
- NHSII (1991-2017)
- Health Professionals Follow-Up Study (HPFS, 1986-2012).
Patient conditions were measured using a 6- or 7-question form over the phone. Of the 159,347 participants, 82.6 percent were women, and the average age was 44.3 years.
Individuals who adhered most closely to the DASH diet were strongly associated with global cognition. Global cognition is a person’s overall ability across domains such as episodic memory, semantic memory, perceptual speed, and visuospatial ability/perceptual orientation. In general, participants with higher diet scores also reported lower body mass indices (BMIs) and a lower overall prevalence of health issues.
Diets that include higher intakes of vegetables and fish, rather than red and processed meats, are preferred. The DASH diet prioritizes heart health by focusing on daily and weekly goals rather than cutting out entire food groups. This means prioritizing foods like vegetables, fruits, whole grains, fat-free or low-fat dairy products, beans, poultry, and fish. Limited foods include fatty meats, tropical oils, sugary drinks, and full-fat dairy products.
From this study, researchers found that products such as leafy green and yellow vegetables, whole grains, wine, fish, salad dressings, coffee, and tea were positively associated with better cognition. Conversely, items like fried foods, non-fried potatoes, cream soup, red meat, processed meat, and eggs were negatively associated.
Diets like DASH, which have a lower potential for inflammation and hyperinsulinemia, are associated with a lower risk of SCD.
Study Limitations
While this study can be helpful for providers in knowing how best to assist their patients with supporting cognitive health, there are key limitations to acknowledge:
- Lack of racial diversity: About 96 percent of participants were white, while only 1.3 percent were Black.
- Limited generalizability: Results may not fully apply to more diverse patient populations.
- Self-reported dietary data: Subject to recall bias (participants not accurately remembering past events, leading to incorrect data).
- Observational design: Unable to establish causation.
Due to these limitations, there is only so much to take from this study, and more research is needed with better racial representation — especially among Black patients, who are disproportionately affected by both cognitive decline and structural barriers in healthcare.
Addressing Disparities in Cognitive Health
While this study did not focus specifically on racial disparities, its findings exist within a broader context.
Black Americans face higher rates of cognitive decline, but are underrepresented in clinical trials and may face barriers to early and accurate diagnosis. Factors such as access to quality healthcare, socioeconomic status, chronic disease burden, and systemic bias all contribute to these disparities.
Providers can help reduce this bias and improve their patients’ overall health by providing ample, culturally relevant information about the importance of diet for cognitive function. They can also ensure that patients receive equitable and thorough cognitive assessments, rather than brief or subjective evaluations.
To improve cognitive health for all patients, providers can educate patients on lifestyle changes that can significantly impact it, such as dietary changes.
Final Takeaway
This latest research adds to the growing evidence that long-term adherence to healthy dietary patterns — particularly the DASH diet — may help preserve cognitive function with age.
Yet, the lack of diversity in the study population highlights a persistent gap in research. More diverse studies are necessary to better understand how these findings translate across different populations.
In the meantime, providers serving Black communities can use this evidence to encourage healthy diets that support cognitive function — particularly among those aged 45 to 54. They should also continue to address the systemic inequities that shape cognitive health outcomes in Black communities.