Effects of saffron supplementation on improving sleep quality: a meta-analysis of randomized controlled trials.
Level 1 - systematic review of randomized trials
Meta-analysis of randomized controlled trials
PubMed 35325766 · doi:10.1016/j.sleep.2022.03.001
What was done
Systematic review and meta-analysis of randomized controlled trials (RCTs) searched across PubMed, Embase, Cochrane Library, and other databases up to October 2021. The study evaluated the effect of saffron supplementation on sleep quality across various adult populations (healthy adults, insomnia, type 2 diabetes, and patients under methadone maintenance treatment). Risk of bias was evaluated using the Cochrane risk-of-bias tool. Outcomes assessed included the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Restorative Sleep Questionnaire (RSQ).
What was found
Compared with placebo, saffron supplementation resulted in statistically significant improvements across all measured sleep outcomes: - PSQI: Mean Difference (MD) -2.14 (95% CI: -2.86 to -1.42; P < 0.01) - ISI: MD -2.63 (95% CI: -3.70 to -2.55; P < 0.01) - RSQ: MD 7.05 (95% CI: 1.48 to 12.62; P = 0.01) Subgroup analysis indicated that a dose of 100 mg/day achieved a stable curative effect, with no serious adverse events reported.
Why it matters
This review synthesizes clinical trial evidence suggesting saffron may serve as an effective dietary supplement to improve subjective sleep quality and reduce insomnia severity.
Limits
The abstract omits the total number of included RCTs and total sample size (n). The findings rely entirely on subjective questionnaires rather than objective sleep measures (such as actigraphy or polysomnography), populations evaluated were heterogeneous, and long-term efficacy and safety remain unconfirmed.