Background: The inclusion of nuts in the diet has been explored as a dietary approach for supporting cognition health across the lifespan. However, research on the types of nuts and their effects on various cognitive domains remains limited, especially in Chinese populations.

Methods: This cross-sectional study investigated the associations of tree nut and peanut consumption with cognitive function and mild cognitive impairment (MCI) risk among middle-aged and older adults from the Chinese Square Dancer Cohort. Data on nut consumption were collected using a semi-quantitative food frequency questionnaire. Cognitive function was assessed by the neuropsychological tests, such as the Verbal Fluency Test (VFT), Auditory Verbal Learning Test (AVLT), Trail Making Test-B (TMT-B), and the Digit Symbol Substitution Test (DSST), and the diagnosis of MCI was conducted following Petersen’s criteria. Multiple linear and logistic regression models were utilized to examine the relationship between the consumption of tree nut and peanut and cognitive performance, as well as the likelihood of MCI.

Results: This study included 4,275 adults aged 55 and above. After controlling demographic characteristics, lifestyle factors, other dietary factors, and history of chronic disease, tree nut consumption was positively associated with global cognition scores (P for trend < 0.001). Compared with non-consumers of tree nuts (0 g/day), the β values (95% confidence intervals, 95% CIs) were 0.10 (0.06, 0.15) for 0.01–4.99 g/day, 0.12 (0.06, 0.18) for 5.00–9.99 g/day, and 0.15 (0.10, 0.20) for ≥10.00 g/day. Participants consuming ≥10.00 g/day of tree nuts also had lower odds of MCI than non-consumers (odds ratio [OR] = 0.69, 95% CI: 0.55, 0.87). As for peanuts, no significant association with MCI was observed after full adjustment. Peanut consumption showed weaker and non-linear associations with global cognition; compared with non-consumers, the β values (95% CIs) were 0.07 (0.03, 0.12) for 0.01–4.99 g/day.

Conclusions: Higher tree nut consumption was associated with better overall cognitive performance and lower odds of MCI. Peanut consumption showed weaker and non-linear associations with global cognition, but was not significantly associated with MCI after full adjustment.

Sleep disturbances have become a pressing public health problem. The association between diet and sleep health has attracted increasing attention in recent years. This study aimed to elucidate the associations of dietary carbohydrate amount and carbohydrate quality with sleep quality. This study was conducted among 4772 participants with a mean age of (62.4 ± 6.3) years in the Lifestyle and Healthy Aging of Chinese Square Dancer Study. Dietary data were collected using a 64-item food frequency questionnaire. Carbohydrate quality was assessed by the carbohydrate quality index (CQI), which is based on four components: dietary fiber intake, glycemic index, whole grain/total grain ratio, and solid carbohydrate/total carbohydrate ratio. Sleep quality was evaluated by the Pittsburgh sleep quality index. Multivariable logistic regression analysis was performed to analyze the association of carbohydrate amount and quality with sleep quality. After controlling for sociodemographic, lifestyle, and multiple disease-related factors, the odds ratio for the highest vs. the lowest quintile of the CQI was 0.64 (95% confidence interval (CI) 0.53, 0.78; P-trend < 0.0001). In contrast, no significant associations were observed between carbohydrate amount and sleep quality. The findings suggest that higher dietary carbohydrate quality, rather than carbohydrate amount, was associated with better sleep quality. This study provided a diet-related sleep-improving strategy for the general population.

Specific carotenoid (e.g., β-carotene, lutein, lycopene) has potential benefits for cognitive health demonstrated in both human and animal studies. To mimic the composition of carotenoids in the human diet and to avoid the overdose of any specific carotenoid, we developed a mixture of 6 carotenoids (7.5 mg/(kg·day), including 9.0% α-carotene, 35.8% β-carotene, 12.2% lutein, 1.6% zeaxanthin, 41.0% lycopene and 0.4% β-cryptoxanthin) and investigated its long-term neuroprotective effect and potential mechanism in APP/PS1 mice, a well-established animal model for Alzheimer’s disease. Initiated at 3 months with a total of 4 months’ gavage intervention, the dietary carotenoids mixture was found to alleviate cognitive impairment and amyloid β deposition in the brain (P < 0.05). Consistently, dietary carotenoids mixture restored Nissl bodies and the density of dendritic spines, and increased protein expression of Synapsin and PSD95 in the hippocampus and cortex of APP/PS1 mice (P < 0.05). In addition, carotenoids were also found to reduce oxidative stress and inflammation level and increase autophagy (P < 0.05). Importantly, carotenoids have been shown to up-regulate the expression of silent information regulator 1 (SIRT1) and brain-derived neurotrophic factor (BDNF) in the brain (P < 0.05). Together, long-term intake of dietary carotenoids mixture could alleviate the cognitive deficit in APP/PS1 mice, wherein the SIRT1/BDNF pathway might play an important role. Our findings could contribute to the development of effective dietary and nutritional intervention strategies for delaying neurodegeneration in the aging population.