Tart Cherry Juice for Better Sleep? Research Says Yes!

observational-study PMID: 28901958

Quick Summary: A small study found that drinking tart cherry juice helped older adults with insomnia sleep longer and more efficiently. The juice may work by increasing the body's use of tryptophan, an amino acid important for sleep.

Does Tart Cherry Juice Help You Sleep?

Yes, according to this research! People who drank tart cherry juice for two weeks slept an average of 84 minutes longer each night. They also reported better sleep quality. This is because tart cherry juice may help your body use tryptophan more effectively.

What The Research Found

Better Sleep: People in the study slept longer and felt like they slept better.

Tryptophan Boost: The study suggests tart cherry juice helps your body use tryptophan, which is needed to make melatonin, the sleep hormone.

Less Inflammation: The juice also seemed to reduce inflammation, which can disrupt sleep.

Study Details

Who was studied: 8 adults over 50 with insomnia (trouble sleeping).

How long: Participants drank the juice for two weeks.

What they took: 240 mL (about 1 cup) of tart cherry juice twice a day.

What This Means For You

Natural Sleep Aid: Tart cherry juice could be a natural way to improve your sleep.

Talk to Your Doctor: Before making big changes to your diet, talk to your doctor.

Try It Out: If you have trouble sleeping, you might consider adding tart cherry juice to your bedtime routine.

Study Limitations

Small Study: Only a few people were in the study, so more research is needed.

Short Time: The study only lasted two weeks, so we don't know if the effects last long-term.

Not for Everyone: The study focused on older adults without sleep apnea.

Key Findings

This 2018 pilot study found that Montmorency tart cherry juice (240 mL twice daily) significantly increased sleep time by 84 minutes (p = 0.0182) and improved sleep efficiency on the Pittsburgh Sleep Quality Index (PSQI) (p = 0.03) in elderly adults (≥50 years) with insomnia. The study identified two potential mechanisms:
1. Reduced tryptophan degradation: Serum kynurenine-to-tryptophan ratio decreased, indicating enhanced tryptophan availability.
2. Anti-inflammatory effects: Prostaglandin E2 levels dropped, suggesting reduced inflammation.
In vitro experiments further demonstrated that procyanidin B-2, a cherry juice compound, dose-dependently inhibited indoleamine 2,3-dioxygenase (IDO), an enzyme that degrades tryptophan and promotes inflammation.

Study Design

Type: Placebo-controlled, balanced crossover trial (observational study).
Participants: 11 adults ≥50 years with insomnia; 8 completed the study after excluding 3 with sleep apnea.
Duration: 2-week intervention periods (cherry juice or placebo) separated by a 2-week washout.
Methods: Sleep was assessed via polysomnography (gold-standard objective measure) and five validated questionnaires. Serum biomarkers (IDO activity, kynurenine-to-tryptophan ratio, prostaglandin E2) were measured. In vitro tests evaluated procyanidin B-2’s IDO inhibition.

Dosage & Administration

Dose: 240 mL of Montmorency tart cherry juice twice daily.
Administration: Commercially available juice; exact concentrations of procyanidin B-2 and anthocyanins were quantified but not specified in the summary. Placebo matched in appearance and taste but lacked active compounds.

Results & Efficacy

Objective sleep improvement: Polysomnography showed +84 minutes total sleep time (p = 0.0182).
Subjective sleep efficiency: PSQI score improved (p = 0.03), though other questionnaires (e.g., Insomnia Severity Index) did not.
Biomarker changes:
Kynurenine-to-tryptophan ratio decreased (p < 0.05), indicating reduced IDO activity.
Prostaglandin E2 levels fell (p < 0.05), suggesting anti-inflammatory effects.
In vitro: Procyanidin B-2 inhibited IDO in a dose-dependent manner, supporting its role in preserving tryptophan.

Limitations

Small sample: Only 8 completers, limiting statistical power and generalizability.
Short duration: 2-week intervention may not reflect long-term efficacy or safety.
Population specificity: Excluded participants with sleep apnea; results apply only to non-apneic elderly individuals.
Unmeasured variables: Direct tryptophan levels and melatonin concentrations were not reported.
Blinding concerns: Placebo design details (e.g., participant blinding) were unspecified, risking bias.
In vitro extrapolation: Mechanistic findings in Caco-2 cells require human validation.

Clinical Relevance

For elderly adults with insomnia, tart cherry juice may offer a non-pharmacological option to increase sleep duration and efficiency. The proposed mechanism—procyanidin B-2 inhibiting IDO to boost tryptophan availability—highlights a novel pathway linking dietary compounds to sleep regulation. However, due to the study’s small size and short duration, these findings should be considered preliminary. Larger, longer trials are needed to confirm efficacy and explore whether IDO inhibition and reduced inflammation are consistent drivers of sleep improvement. Practitioners might cautiously recommend tart cherry juice as an adjunct to sleep hygiene practices, while prioritizing safety monitoring (e.g., falls, drug interactions).

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