Effects of folic acid supplementation on cognitive impairment: A meta-analysis of randomized controlled trials.

OBJECTIVE: With the increasing number of patients with cognitive impairment, nonpharmacological ways to delay cognitive impairment have attracted people's attention, such as lifestyle changes and nutritional supplementation. Folic acid supplementation appears to be a promising treatment option. However, it remains controversial whether folic acid supplementation is effective in delaying adult's cognitive impairment. Therefore, we conducted a meta-analysis to analyze the effects of folic acid supplementation on different cognitive impairments. METHODS: We systematically searched PubMed, Web of Science, EMbase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI), WanFang and VIP databases for randomized controlled trials on January 22, 2024. The included population comprised those diagnosed with cognitive impairment. We included trials that compared folic acid treatment with placebo, other dosing regimens, or other intervention controls. Conducting quality evaluation of included studies according to the Cochrane Risk of Bias tool. Statistical analyses were performed using Review Manager software. RESULTS: Twenty-two trials, including 3604 participants, met inclusion criteria. Compared with controls, the cognitive function of Alzheimer's disease (AD) patients showed improvement with folic acid supplementation: supplementation with < 3 mg (standardized mean differences (SMD) = 0.15, 95% confidence interval (CI) -0.10 to 0.41), and supplementing with ≥ 3 mg folic acid could improve cognitive function in AD patients (SMD = 1.03, 95% CI 0.18 to 1.88). Additionally, it reduced homocysteine (HCY) levels (mean differences (MD) = -4.74, 95% CI -8.08 to -1.39). In mild cognitive impairment (MCI) patients, cognitive function improved with folic acid supplementation: supplementation with > 400 µg (SMD = 0.38, 95% CI 0.13 to 0.63), and supplementation with ≤ 400 µg (SMD = 1.10, 95% CI 0.88 to 1.31). It also reduced HCY levels at intervention ≤ 6 months (MD = -3.93, 95% CI -5.05 to -2.82) and intervention > 6 months (MD = -4.38, 95% CI -5.15 to -3.61). However, supplementing with folic acid did not improve cognitive function in vascular cognitive impairment (VCI) patients, with folic acid supplements < 3 mg (SMD = -0.07, 95% CI -0.23 to -0.08), folic acid supplements ≥ 3 mg (SMD = 0.46, 95% CI -0.57 to 1.49), however, it reduced HCY levels at intervention > 6 months (MD = -5.91, 95% CI -7.13 to -4.69) and intervention ≤ 6 months (MD = -11.15, 95% CI -12.35 to -9.95). CONCLUSIONS: Supplement folic acid is beneficial to the cognitive profile of patients with MCI, supplementation with ≥ 3 mg folic acid can improve cognitive function in AD patients.

Comparative study on inhibitory effects of ferulic acid and p-coumaric acid on Salmonella Enteritidis biofilm formation.

Biofilm cells exhibit higher resistance than their planktonic counterparts to commonly used disinfectants in food industry. Phenolic acids are promising substitute offering less selective pressure than traditional antibiotics. This study aims to evaluate the inhibitory effects of ferulic acid (FA) and p-coumaric acid (p-CA) on Salmonella Enteritidis biofilm formation and explore the underlying inhibitory mechanisms. The minimal inhibitory concentration (MIC) of FA and p-CA were 1.0 and 0.5 mg/ml, respectively. The sub-inhibitory concentration (1/8 MIC) significantly decreased biofilm formation without growth inhibitory effects. The biomass and extracellular polymeric substances (EPS) of S. Enteritidis biofilm as well as the bacterial swimming and chemotaxis abilities were significantly decreased when exposed to sub-MIC concentrations of FA and p-CA. These two phenolic acids showed high affinity to proteins involved in flagella motility and repressed the S. Enteritidis biofilm formation-related gene expressions. Furthermore, these two phenolic acids maintained high antibiofilm efficiency in simulated food processing conditions. This study provided valuable information of multiple phenotypic and molecular responses of S. Enteritidis to these two phenolic acids.