Effects of saffron (Crocus sativus L.) on cognitive function. A systematic review of RCTs.

INTRODUCTION: Improvement of cognitive function may be desirable for healthy individuals and clinically beneficial for those with cognitive impairment such as from Alzheimer's disease (AD) or mild cognitive impairment (MCI). The aim of this systematic review is to investigate the cognitive effects of oral saffron intake, in patients with MCI/AD and/or in non-demented individuals, by following the PRISMA guidelines. METHODS: We performed a literature search on MedLine, Cochrane library, and ClinicalTrials.gov to identify randomized controlled trials (RCTs) investigating the effects of oral saffron administration in patients with MCI/AD and/or in non-demented individuals. RESULTS: Five studies (enrolling 325 individuals) met our inclusion criteria. Four studies included patients with MCI/AD, and one study included cognitively normal individuals. Saffron was well-tolerated in all groups. Regarding cognitively impaired patients, scores on Alzheimer's Disease Assessment Scale-cognitive subscale or Mini mental state examination were significantly better when saffron was compared with placebo and did not differ significantly when saffron was compared with donepezil or memantine. Saffron effects on functional status were similar with its effects on cognition. CONCLUSIONS: Saffron was shown to be equally effective to common symptomatic drugs for MCI/AD and resulted in no difference in the incidence of side effects, when compared with placebo or drugs. The promising results should be seen cautiously, since the evidence was derived from studies with potentially high risk of bias (ROB). RCTs with larger sample sizes and low ROB are required to definitively assess the potential role of saffron as an MCI/AD treatment.

Atrial fibrillation and cognitive function in patients with heart failure: a systematic review and meta-analysis.

Cognitive impairment and dementia are established complications of heart failure (HF) in adult patients and impair medication adherence and self-care. Atrial fibrillation (AF) is suggested to play an independent role in the cognitive decline in patients with HF. The objective of this systematic review was to assess the effect of AF on cognitive function in these patients. Medline (PubMed), Scopus, and the CENTRAL databases were queried from their inception up to April 30, 2016. The search included primary research articles evaluating the effect of AF on cognition in HF patients. There were five eligible studies, including a total of 1670 patients with HF; of these, 449 (26.9%) had AF. Different AF types were studied, including persistent, paroxysmal, or permanent. Four cognitive tests were used to assess cognitive function (Mini-Mental State Examination, Short Portable Mental Status Questionnaire, Modified Mini-Mental Examination, and Montreal cognitive assessment tool). Using the inverse variance method and a random effects model, we observed that presence of AF was significantly associated with increased risk of cognitive impairment in HF patients (odds ratio [OR], 1.94; 95% confidence interval [CI], 1.30-2.87), although with significant heterogeneity (I 2  = 39%). This heterogeneity can be attributed to the different populations and types of AF studied as well as to varying cognitive assessment methods. Concomitant AF may exacerbate cognitive dysfunction in HF patients. However, data are sparse and heterogeneous. Well-designed, prospective studies are needed to (a) establish a causative link and (b) identify the underlying mechanism in order to design appropriate interventions to attenuate risk of cognitive impairment in patients with HF.