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A new study from South Dakota State University's School of Health and Human Sciences indicates that fiber, carotenoids and various micronutrients may support healthy brain aging in older adults. 

Adults over the age of 65 are at increased risk of cognitive decline and developing types of neurodegenerative conditions, like Alzheimer’s disease. Could certain foods and dietary patterns help prevent or slow these issues from occurring?

A study from South Dakota State University's School of Health and Human Sciences has provided new evidence that fiber and various micronutrients may help with better brain health and mental processes in older adults.

, led by assistant professor Samitinjaya Dhakal, was conducted by analyzing the dietary intake, eating patterns and cognitive function of 72 adults aged 65 and older in the Brookings area. 

"The increasing burden of cognitive diseases represents a major public health challenge that is driven mainly by an aging population and limited prevention options," Dhakal said. "Existing evidence suggests that modifiable lifestyle factors, including diet, may offer a significant opportunity to prevent or delay cognitive decline."

Based on the collected the data, the research team was able to link diets high in fiber, healthy unsaturated fats and micronutrients such as: Vitamins A and E, magnesium and potassium with better brain health and memory. The results also showed that carotenoids, a type of molecule that gives fruits, vegetable and flowers their bright colors, were linked to better cognitive function.

The study also revealed some troubling insights regarding nutrient intake. Nearly all the participants reported diets lacking in overall nutrient adequacy for their age, including many vitamins, calcium, potassium, and dietary fiber. The data also revealed that refined grains — often found in white bread, certain cereals, pasta and crackers — were negatively associated with cognitive function and memory.

“Our findings suggest that fiber, unsaturated fats, carotenoids, and key micronutrients play a significant role in supporting healthy brain aging, while an over-reliance on refined grains may be at odds with cognitive health," Dhakal said. "Ultimately, these findings underscore the urgent need for targeted dietary interventions to bridge the nutrient gap in older populations.”

As Dhakal notes, the study has some notable limitations, primarily due to its exploratory nature, modest sample size and the use of self-reported dietary data. However, the results align with established biological pathways, as the specific nutrients identified in the study such as fiber, carotenoids and unsaturated fats are known to influence brain health through well-documented biochemical processes. For example, the body ferments fiber into short-chain fatty acids which promote neuronal growth and anti-inflammatory signaling. This process reduces systematic inflammation, which is a key driver of cognitive decline.

"Our research highlights that even within a relatively healthy community, there is a significant 'nutrition gap' that could be impacting cognitive longevity," Dhakal explained. "Identifying these modifiable dietary factors is only the first step; the real priority now is developing targeted counseling and interventions that help older adults actually meet these recommendations in their daily lives."

Looking ahead, Dhakal emphasizes that while these cross-sectional findings are compelling, they are just the beginning. Future longitudinal and interventional studies are necessary to determine if specific dietary changes can actively slow the progression of cognitive decline and promote more resilient brain aging.

Contributing authors on this study include Nirajan Ghimire and Sophia Bass — SDSU students and research assistants in Dhakal's lab.

Funding for this study was provided by SDSU's College of Education and Human Sciences Piot Study Funding Program.