Effects of almond consumption on sleep quality in adults: a randomized controlled trial.

BACKGROUND

Sleep disturbances are associated with adverse metabolic, neurocognitive, and inflammatory outcomes. This study examined the effects of a 5-month whole-almond intervention on objective and subjective sleep parameters, biochemical and inflammatory markers in adults with poor sleep quality.

METHODS

In this open-label, parallel-arm, randomized controlled community-based trial with blinded outcome assessment, 175 adults aged 21-55 years with poor sleep quality (Pittsburgh Sleep Quality Index [PSQI] ≥ 5 and/or Epworth Sleepiness Scale [ESS] ≥ 10) were randomized to either an almond group (n = 88) or a control group receiving an isocaloric snack (n = 87) using computer-generated allocation. We hypothesized that regular almond consumption would improve subjective and objective sleep outcomes. Assessments conducted at baseline and after 5 months included polysomnography, PSQI, ESS, anthropometry, and biochemical markers. Per-protocol analyses were performed to evaluate between-group differences in mean changes.

RESULTS

Baseline characteristics were comparable between groups (p > 0.05). The almond group demonstrated significantly greater improvement in subjective sleep efficiency compared with controls (mean change: 9.7 ± 13.4 vs. 5.4 ± 10.6; p = 0.021). After adjustment for baseline values and sex, the almond group had lower global PSQI scores (3.94 ± 0.24 vs. 4.79 ± 0.32; p = 0.013), higher subjective sleep efficiency (94.45 ± 0.72% vs. 91.85 ± 0.42%; p = 0.012), and shorter subjective sleep latency (18.46 ± 2.25 vs. 26.29 ± 2.27 min; p = 0.016) than the control group. No significant treatment effects were observed for most PSG-derived sleep parameters, although wake during sleep tended to be lower in the almond group (p = 0.081). Endline melatonin concentrations were significantly higher following almond consumption (250.63 ± 15.98 vs. 206.19 ± 16.07 pg./mL, p = 0.050), whereas no significant differences were observed for other biochemical or anthropometric outcomes. A higher proportion of participants in the almond group achieved a clinically meaningful improvement in PSQI score and demonstrated reduced wake during sleep (p = 0.043).

CONCLUSION

Almond consumption was associated with improvements in subjective sleep efficiency and sleep continuity in adults with poor sleep quality. These findings suggest that almonds may enhance perceived sleep quality, with slight objective improvements among responders.

CLINICAL TRIAL: https://ctri.nic.in/Clinicaltrials/showallp.php?mid1=80395&EncHid=&userName=Almond, Clinical Trials Registry-India (CTRI/2023/02/049727; registered 15 February 2023).