Summary:
Cognitive decline in older adults is a major public health concern, increasing disability and caregiving burdens. Traditional pharmacological treatments have limited efficacy and potential side effects, prompting interest in lifestyle factors such as diet. The gut microbiota has emerged as a key mediator between nutrition and brain health, influencing neuroinflammation, neurotransmitter production, and cognitive function through the gut-brain axis. Diet plays a critical role in shaping the gut microbiome, with fiber-rich foods, polyphenols, and fermented products promoting beneficial bacteria. To quantify the impact of diet on gut microbiota, the Dietary Index for Gut Microbiota (DI-GM) was developed, incorporating 14 food groups known to influence microbial diversity and function. Higher DI-GM scores reflect diets rich in fermented dairy, whole grains, and fiber, and low in red/processed meats. This study aimed to evaluate the relationship between DI-GM scores and cognitive performance in older adults. Data from 2,207 participants were analyzed. Results showed a significant positive association between higher DI-GM scores and overall cognitive function. Analyses confirmed a steadily consistent positive relationship, and it was similar across all age, gender, and other demographic groups. These findings suggest that diets promoting beneficial gut microbiota, as captured by the DI-GM, may support cognitive function in older adults.
Abstract:
Background: Significant correlations exist between gut microbiota, dietary habits, and cognitive function; the objective of this research was to evaluate the correlation between the dietary index for gut microbiota (DI-GM) and cognitive performance. The primary objective of this study was to evaluate the strength and direction of the association between Dietary Index for Gut Microbiota (DI-GM) scores and cognitive performance among older adults, and to further explore whether a dose-response relationship exists, thereby informing potential dietary strategies for cognitive risk stratification.
Methods: Complete DI-GM and cognitive function evaluation data for older adults were taken from the 2011–2014 National Health and Nutrition Examination Survey (NHANES) database. Cognitive function was assessed by standardized test scales. The weighted linear regression models were used to examine the association between DI-GM and cognitive function. Restricted cubic spline and threshold analysis evaluated the existence of non-linear correlations among variables. Subgroup studies were conducted to evaluate the consistency of the connection across different demographics.
Results: The outcome analysis showed that among the 2,207 participants, there was a positive and statistically significant relationship between higher DI-GM scores and scores of beneficial gut microbiota and total scores of cognitive functions (β = 0.03, 95% CI: 0.01–0.05, P = 0.034). Both RCS and threshold analyses confirmed the linear correlation between DI-GM and beneficial gut flora and total scores of cognitive functions (P for non-linear > 0.05). Additionally, our study demonstrated that the correlation between DI-GM and total scores of cognitive functions was maintained in subgroup analyses (P for interaction > 0.05).
Conclusion: The findings of the study indicated that DI-GM profoundly impacts cognitive performance, which suggests that dietary modifications based on DI-GM may help lower the level of cognitive impairment in the elderly, but further high-caliber research is required to elucidate the precise processes and application modalities, and to provide more effective strategies for improving cognitive function in the elderly.
Article Publication Date: 07/08/2025
DOI: 10.3389/fnut.2025.1618220
