Homocysteine (Hcy) is a risk factor for brain atrophy, cognitive impairment, and dementia. Vitamin B₁₂ and folate are cofactors necessary for the methylation of Hcy. However, there is some debate regarding the differing levels of plasma Hcy and serum folate and vitamin B₁₂ among healthy controls, patients with mild cognitive impairment (MCI), and patients with Alzheimer’s disease (AD). This study aimed to evaluate how the levels of plasma Hcy and its biological determinants, folate and vitamin B₁₂, are related to MCI and AD in older Chinese adults. This is a case-control study including 112 subjects with MCI, 89 AD patients and 115 healthy controls. Diagnosis of AD was made according to the NINCDS-ADRDA and MCI with modified Petersen’s criteria. Serum folate and vitamin B₁₂ concentrations were analyzed by radioimmunoassay, and plasma Hcy was assessed by a high-performance liquid chromatography-fluorescence method. Multivariate analysis of regression was used to examine the odds ratio (OR) of MCI or AD with Hcy or vitamin levels. Results have shown that serum folate and vitamin B₁₂ levels were significantly lower, but the plasma Hcy level was higher, in patients with MCI and AD than in healthy controls. Multivariate regression analyses showed that subjects in the lowest folate tertile had significantly higher adjusted ORs for MCI (OR: 3.07; 95% confidence interval [CI]: 1.12, 8.07) and AD (3.42; 95% CI: 1.15, 8.34) compared to subjects in the highest tertile. The highest Hcy tertile was significantly associated with MCI (adjusted OR: 2.81; 95% CI: 1.15, 4.73) and AD (adjusted OR: 3.64; 95% CI: 1.13, 9.04) compared to the lowest tertile. No association existed between low vitamin B₁₂ levels and AD or MCI (p > 0.05). Low blood levels of folate and vitamin B₁₂ and elevated Hcy levels were associated with MCI and AD in older Chinese adults, and the association was stronger for AD.

Background: Dining out has become increasingly prevalent in China, which is associated with higher intakes of energy, fat and sodium, elevating the risk of diet-related non-communicable diseases. However, evidence on color-coded nutrition labels for onsite prepared meals remains scarce. This study aimed to examine consumers’ perceptions of Dish-Choice, a three-color-coded onsite label, in comparison with the standard Nutrition Facts Label (NFL), to evaluate subjective perceptions of this novel label. Methods: A self-controlled trial was conducted among 3008 diners from canteens in Shanghai, with completing questionnaires twice: first on NFL perceptions, then three months later on Dish-Choice. Logistic regression and paired-sample comparison were used for analysis. Results: Compared with the NFL, Dish-Choice was associated with higher perceptual scores, with greater changes in overweight/obese, males, lower socio-economic status (SES) groups and those with poor dietary quality. Conclusions: The Dish-Choice label elicits more positive perceptual responses across multiple perceptual constructs. It is particularly well-received among vulnerable populations with lower health literacy, including men, lower-SES groups, and individuals with poor dietary habits. This supports its potential as a public health tool for on-site dining settings, though further research is needed to confirm its impact on actual food choices.