The effects and potential mechanisms of folic acid on cognitive function: a comprehensive review

Cognitive impairment and dementia are major neurocognitive disorders that cause a noticeable decline in cognitive abilities, including memory and thinking skills. The effectiveness of using folic acid as an adjuvant for management of neurocognitive disorders is not well-known. This paper explains the role of folic acid, including its usefulness, effectiveness, adverse side effects, and active mechanisms on cognitive functions of the elderly. In the current study, we reviewed clinical and experimental studies investigating the use of folic acid prior to November 2017, using PubMed, ISI Web of Knowledge, Science Direct, Scopus, Ovid, and Cochrane Library databases. A total of 142 articles were retrieved by electronic search. Based on the preset inclusion and exclusion criteria, a total of 36 articles were retrieved for full text analysis. According to data obtained from the review, it seems that folic acid supplementation may improve cognitive function by decreasing homocysteine (Hcy), vascular care, attenuating inflammatory status, modification of cerebral folic acid deficiency, and antioxidant responses. Specifically, people with high levels of Hcy have a better response to folic acid supplementation, which may arise from low serum folate concentration.