We evaluated whether red meat consumption, within diets of both high and low healthy eating index (HEI) quality, was associated with differences in brain health-critical micronutrient adequacy, mental health, diet quality, or fecal microbiota composition. Using data from 3643 adults in the American gut project, participants were stratified into four groups: high-HEI (≥ 80) with red meat (HH-R), high-HEI without red meat (HH-NR), low-HEI (< 80) with red meat (LH-R), and low-HEI without red meat (LH-NR). HH-R had higher protein intake and lower carbohydrate intake than HH-NR, with saturated fat levels within recommended limits. Brain health-critical micronutrient adequacies (selenium, vitamin B12, zinc, calcium, vitamin D3, choline) were significantly higher in HH-R (p < 0.001) than HH-NR. Higher HEI scores, irrespective of red meat consumption, were associated with reduced odds of depression (logOR = -2.22), PTSD (logOR = -3.80), and bipolar disorder (logOR = -5.90). Fecal microbiota diversity and richness were highest in HH-R, with higher Bacteroides caccae (p_adj = 0.003) and Clostridium hathewayi (p_adj < 0.001), while HH-NR showed higher Bifidobacterium adolescentis and Bacteroides eggerthii (p_adj < 0.001). Therefore, these findings suggest that the inclusion of red meat in a high-HEI diet improves brain health-supporting micronutrient adequacy without adverse effects on mental health or microbial diversity.

We evaluated whether red meat could be integrated into a high Healthy Eating Index (HEI) diet to improve brain health-critical nutrient adequacy without compromising diet quality, mental health, or gut microbiota. Using data from 3,643 adults in the American Gut Project, participants were stratified into four groups: high-HEI (≥ 80) with red meat (HH-R), high-HEI without red meat (HH-NR), low-HEI (< 80) with red meat (LH-R), and low-HEI without red meat (LH-NR). Both high-HEI groups maintained healthy BMI values regardless of red meat intake. HH-R had higher protein intake and lower carbohydrate intake, with saturated fat levels within recommended limits. Brain health-critical micronutrient adequacies (selenium, vitamin B12, zinc, calcium, vitamin D3, choline) were significantly higher in HH-R (p < 0.001). Higher HEI scores, irrespective of red meat consumption, were associated with reduced odds of depression (logOR= -2.22), PTSD (logOR= -3.80), and bipolar disorder (logOR= -5.90). Gut microbiota diversity and richness were highest in HH-R, with increased Bacteroides caccae (p_adj = 0.003) and Clostridium hathewayi (p_adj < 0.001), while HH-NR showed higher Bifidobacterium adolescentis and Bacteroides eggerthii (p_adj < 0.001). Therefore, these findings suggest that the inclusion of lean red meat in a high-HEI diet improves brain health-supporting micronutrient adequacy without adverse effects on mental health or microbial diversity.

Objectives: The rapid aging of the U.S. population has raised concerns about age-related cognitive decline and Alzheimer’s disease. Therefore, we aimed to characterize diet quality, nutrient intake, and to examine the associations between specific dietary components and cognitive performance in older adults. Design: Cross-sectional observational study. Setting: Community-based recruitment. Participants: Data from 72 community-dwelling adults aged 65 years and older was analyzed. Measurements: Cognitive performance was assessed using subtests from the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) battery, evaluating episodic memory (Word List Memory/Recall/Recognition), visuospatial skills (Constructional Praxis), and executive function (Verbal Fluency). A composite cognitive score was calculated from memory and visuospatial subtests. Habitual dietary intake was evaluated using structured 24-h recalls to calculate nutrient intake and the Healthy Eating Index score, supplemented by the Short HEI questionnaire. Demographics, health history, depressive symptoms (Patient Health Questionnaire-9), and sleep quality (Pittsburgh Sleep Quality Index) were also collected. Results: Participants demonstrated suboptimal diet quality (mean HEI score 62.9 ± 10.69; recommended >80), with only 9.7% meeting fiber recommendations, 11% meeting calcium or vitamin A recommendations, and 1.4% meeting vitamin D requirements. In bivariate comparisons, higher cognitive performance was observed in younger participants (75.5 vs. 79.5 years; p < 0.01) and females (78% vs. 50%; p = 0.024). Regression models identified significant positive associations between cognitive scores and intakes of dietary fiber (p = 0.007), unsaturated fats (mono- and polyunsaturated; p = 0.012–0.033), protein (p = 0.018), carotenoids (α-carotene, p = 0.001; β-carotene, p = 0.026; lutein + zeaxanthin, p = 0.016), vitamins A (p = 0.044) and E (p = 0.034), and minerals including magnesium (p = 0.006), potassium (p = 0.004), copper (p = 0.008), zinc (p = 0.024), and calcium (p = 0.035). Refined grain intake was inversely associated with cognition (p = 0.011). Conclusions: In this population, dietary components like fiber and micronutrients were positively associated with better cognitive function, and the overall nutrient intake shortfalls observed highlight the need for targeted dietary interventions to support healthy brain aging. Therefore, this work advances our understanding by highlighting potential modifiable nutritional targets for clinical trials focused on delaying or preventing cognitive decline.

Diet quality is essential to healthy aging, yet the effectiveness of common dietary indices in predicting nutritional adequacy in older adults remains unclear. We address the gap by comparing popular indices: Healthy-Eating-Index, Mediterranean-score, and MIND-score. Using linear and multivariate-logistic regression models on a cohort of 72 older adults (mean age:77.5 years), we evaluated associations of the dietary indices with nutrient intake and the likelihood of meeting EAR/AI. Higher HEI-scores predicted greater intake of 12 nutrients (e.g., vitamin D, B12, potassium; all p < 0.05) and increased odds of nutrient adequacy for two. The Mediterranean-score had mixed associations, with higher vitamin C intake but lower adequacy of thiamin and selenium. The MIND score consistently outperformed both, predicting adequacy for 11 essential nutrients and showing the strongest predictive power. Therefore, we highlight HEI and MIND scores as effective for nutritional assessment in older adults, while the Mediterranean score may be limited by cultural context.

Objectives: The rapid aging of the U.S. population has raised concerns about age-related cognitive decline and Alzheimer’s disease. As of 2024, 18% of Americans are ≥65 years—up from 12.4% in 2004—contributing to a projected 7.2 million cases of Alzheimer’s disease among older adults in 2025. Diet is a key modifiable factor for cognitive decline. Therefore, we aimed to characterize diet quality and nutrient intake and to examine the associations between specific dietary components and cognitive performance in older adults in the American Midwest. Design: The study was designed as a cross-sectional observational study. Setting: Community-based recruitment in Brookings, South Dakota, and surrounding areas Participants: A final analytical sample of 72 community-dwelling adults aged 65 years and older Measurements: Cognitive performance was assessed using subtests from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) battery, evaluating episodic memory (Word List Memory/Recall/Recognition), visuospatial skills (Constructional Praxis), and executive function (Verbal Fluency). A composite cognitive score was calculated from memory and visuospatial subtests. Habitual dietary intake was evaluated using structured 24-hour recalls to calculate nutrient intake and the Healthy Eating Index score, supplemented by the Short HEI questionnaire. Demographics, health history, depressive symptoms (Patient Health Questionnaire-9), and sleep quality (Pittsburgh Sleep Quality Index) were also collected. Results: Participants demonstrated suboptimal diet quality (mean HEI score 54.4 ± 9.4; recommended >80), with only 9.7% meeting fiber recommendations, 11% meeting calcium or vitamin A recommendations, and 1.4% meeting vitamin D requirements. In bivariate comparisons, higher cognitive performance was observed in younger participants (75.5 vs. 79.5 years; p< 0.01) and females (78% vs. 50%; p=0.024). Regression models identified significant positive associations between cognitive scores and intakes of dietary fiber (p=0.007), unsaturated fats (mono- and polyunsaturated; p=0.012–0.033), protein (p=0.018), carotenoids (α-carotene, p=0.001; β-carotene, p=0.026; lutein+zeaxanthin, p=0.016), vitamins A (p=0.044) and E (p=0.034), and minerals including magnesium (p=0.006), potassium (p=0.004), copper (p=0.008), zinc (p=0.024), and calcium (p=0.035). Refined grain intake was inversely associated with cognition (p=0.011). Conclusion: In this population, dietary components like fiber and micronutrients were positively associated with better cognitive function, and the overall nutrient intake shortfalls observed highlight the need for targeted dietary interventions to support healthy brain aging.