Baseline folic acid status affects the effectiveness of folic acid supplements in cognitively relevant outcomes in older adults: a systematic review

Background: Folic acid was investigated for decreased concentrations of the same type of cysteine (Hcy), which is considered a risk factor for Alzheimer's disease. However, the conclusions are inconsistent, while supplementing elders with different folic acid states. Method: The PubMed, Science Network and EMBASE databases were searched for randomized controlled trials published over the past decade; The 11/485 study was included on the basis of pre-defined criteria. Cognitive-related results, including cognitive function and brain atrophy, were measured using cognitive scales and magnetic resonance imaging. Results: Significant cognitive benefits were reported in individuals with incomplete folic acid (n s 4); However, individuals with sufficient folic acid (n s 2) do not benefit from supplements, evaluated by the cognitive scale. On the other hand, a significant positive association was established in the participants of plasma Hcy, but the folic acid state was sufficient (n s 2). One study reported that folic acid supplements did not provide any benefit, but folic acid status data were missing. In addition, folic acid supplementation also improves brain atrophy (n s 2). Conclusion: Baseline folic acid status may be a potential factor affecting the results of cognitive function folic acid supplementation in older adults. Older people with insufficient folic acid will benefit from folic acid supplementation.