Insights & Discussion
Cherry juice increases sleep time and efficiency in older adults with insomnia, potentially due to its inhibition of a process that degrades tryptophan and stimulates inflammation.
The study followed a placebo-controlled balanced crossover design, with subjects older than 50 years old with insomnia being randomized to either placebo or cherry juice consumption twice daily for two weeks, with a two-week washout period in between. Sleep was evaluated using polysomnography and five validated questionnaires, while serum measurements were conducted for several bio-indicators. In vitro studies were also performed to determine the ability of cherry juice components to inhibit a specific physiological process.
The study found that sleep time increased by 84 minutes per polysomnography evaluations and sleep efficiency increased per the Pittsburgh Sleep Quality Index. Serum measurements revealed decreased levels of certain bio-indicators suggesting reduced inflammation. In vitro studies also found that components present in cherry juice inhibited a specific process that degrades the amino acid tryptophan, potentially leading to these improved sleep outcomes. Other questionnaires, however, showed no significant differences in results.
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There is evidence to support significant improvements to total sleep time and sleep efficiency with the ingestion of tart cherries.
2023 Current Sleep Medicine Reports Too Sour to be True? Tart Cherries (Prunus cerasus) and Sleep: a Systematic Review and Meta-analysis Stretton B, Eranki A, Kovoor J, Bacchi S, Gupta A, Maddern G, et al.
Systematic Review Cherry Insomnia Sleep
We identified a total of 277 unique records, from which 8 studies of low-moderate methodological quality were included in the systematic review. Meta-analysis of subjectively recalled sleep efficiency (SE) and total sleep time (TST) were not significant. Objective SE, however, was significantly higher in the cherry cohort when compared to placebo with an effect size of 0.63 (95% CI 0.29–0.97, P < 0.01). There was low associated heterogeneity (I2 = 0%). Objective TST was significantly higher in the cherry cohorts, with a pooled effect size of 1.21 (95% CI 0.83–1.58, P < 0.01). There was high associated heterogeneity (I2 = 81.5%).
Consumption of tart cherry juice can increase exogenous melatonin that is beneficial in improving sleep duration and quality and might be of benefit in managing disturbed sleep.
2011 European Journal of Nutrition Effect of tart cherry juice (Prunus cerasus) on melatonin levels and enhanced sleep quality Howatson G, Bell PG, Tallent J, Middleton B, McHugh MP, Ellis J
Randomised Controlled Trial Cherry Melatonin Sleep
Total melatonin content was significantly elevated (P < 0.05) in the cherry juice group, whilst no differences were shown between baseline and placebo trials. There were significant increases in time in bed, total sleep time and sleep efficiency total (P < 0.05) with cherry juice supplementation. Although there was no difference in timing of the melatonin circardian rhythm, there was a trend to a higher mesor and amplitude.