Effect of folic acid on cognitive function in older adults: A systematic review and meta-analysis

Abstract

Dementia is a common problem among the elderly. It is caused by a decline in cognitive abilities. Some studies have shown that folic acid supplements can improve cognitive function in older adults. However, the results are not yet conclusive. The aim of this study was to investigate whether folic acid supplementation can improve cognitive function among older adults. Relevant articles were systematically searched using PubMed, Google Scholar, ScienceDirect, and PMC databases as of June 13,  2024. Randomized controlled trials (RCT) investigating the effect of folic acid supplementation on cognitive function among older adults were included for qualitative and quantitative data syntheses. For meta-analysis, we used a random-effects model to compute the mean difference (MD) and 95% confidence interval (CI). A total of four studies with 1,855 participants were included in this meta-analysis. The meta-analysis revealed that folic acid supplementation did not improve cognitive function as measured by Mini-Mental State Examination (MMSE) score changes (1,310 participants; MD: 0.01; 95%CI: -0.14–0.17; p=0.89). However, a significant improvement by folic acid supplementation was observed based on executive function Z-score (1,610 participants; MD: 0.25; 95%CI: 0.24–0.27; p<0.001). Another improvement was observed in episodic memory Z-score (1,610 participants; MD: 1.31; 95%CI: 1.23–1.38; p<0.001). The heterogeneity was significant in episodic memory Z-score (I²=100%) and executive function Z-score (I²=82%), but not in MMSE (I²=0%). Folic acid improves executive function and episodic memory among the elderly with dementia, yet the effect is suboptimal when measured through MMSE.