Table 2.
Characteristics of included controlled intervention studies
| No. | Reference (year) | Country | Study design | Population | Intervention | Control | Duration | Sleep outcome measurement | Main results |
|---|---|---|---|---|---|---|---|---|---|
| Infants and toddlers (aged 0–3 y) | |||||||||
| 1 | Judge et al (2012)41 | United States | RCT | Healthy pregnant women and their newborn babies (n = 48) | Cereal bars contained fish oil (300 mg DHA/d) | Corn oil | Started from 24 wk gestation and continued until delivery (38–40 wk): 98–112 d | Neonates’ sleep outcome including arousals, QS, AS, active-quiet sleep transition, and sleep-wake transition measured by actigraph | On postnatal day 1, infants of mothers in the DHA intervention group had significantly fewer arousals in QS (t = 2.17, P < 0.05) and arousals in AS (t = 2.21, P < 0.05) compared with infants born to mothers in the placebo group. On postnatal day 2, QS: I: 12.70 ± 5.85, C: 13.70 ± 4.76; active-quiet sleep transition: I: 0.47 ± 0.30, C: 0.41 ± 0.27; sleep-wake transition: I: 51.57 ± 14.54, C: 51.70 ± 11.13. Infants of mothers in the treatment group had significantly fewer arousals in QS (F = 5.72, P < 0.05) than the placebo group when controlling for maternal total weight gain during pregnancy, because maternal weight was significantly correlated with the infant sleep measure. |
| 2 | Boone et al (2019)46 | United States | RCT | Children (n = 377) aged 10–16 mo born at < 35 wk gestation | DHA 200 mg+AA 200 mg/d supplementation | Corn oil (400 mg/d) | 180 d | Nocturnal and daytime sleep duration, and sleep-onset time measured by caregiver-reported BISQ | Nocturnal sleep duration (h) I: 10.0 ± 1.6, C: 9.9 ± 1.5, difference in change (95%CI): 0.24 (−0.05 to 0.53), effect size = 0.16, P = 0.11; TSD (h) I: 12.1 ± 1.8, C: 12.3 ± 1.8, difference in change (95%CI): 0.14 (−0.23 to 0.51), effect size = 0.07, P = 0.32; sleep onset time (min) I: 34.4 ± 42.8, C: 32.1 ± 35.5, difference in change (95%CI): 3.50 (−4.80 to 11.79), effect size = 0.09, P = 0.35; night wakefulness (min): I: 28.6 ± 72.3, C: 26.8 ± 61.1, difference in change −0.95 (95%CI, −15.80 to 13.90), effect size = −0.01, P = 0.82. Although there is no evidence of an overall effect of DHA+AA supplementation on child sleep, exploratory post hoc analyses identified that boys and children whose caregivers had depressive symptomatology may benefit more from the supplementation. |
| Children (aged 4–18 y) | |||||||||
| 3 | Hysing et al (2018)50 | Finland | RCT | Preschoolers between ages 4 and 6 y (n = 232) | Three warm lunch meals per week containing fatty fish. Each meal contained 50–80 g of fatty fish. | Three warm lunch meals per week containing meat. Each meal contained 50–80 g of meat. | 112 d | Parent-reported bedtime and rise time, time in bed, sleep latency, wake after sleep onset, sleep efficiency (ratio of duration of sleep to time in bed). | Time in beda (min) I: 678 ± 42, C: 672 ± 34, change of mean score: I: −5.3 (95%CI, −11.8 to 0.3); C: −5.3 (95%CI, −11.2 to 0.6), P = 0.905. TSD (min) I: 653 ± 45, C: 644 ± 36; change of mean score, I: −1.2 (95%CI, −8.3 to 5.9), C: −1.8 (95%CI, −8.8 to 5.1), P = 0.893. Sleep latency (min): I: 23.0 ± 16.0, C: 26.3 ± 16.8; change of mean score: I: −1.9 (95%CI, −4.7 to 0.9). There were no statistically significant differences between the fish and the meat groups on any of the included sleep measures. |
| 4 | Montgomery et al (2014)18 | United Kingdom | RCT | Healthy children aged 7–9 y (n = 362) who were under performing in reading from mainstream UK schools | Three capsules containing a total of 600 mg of algal DHA/d | Three capsules /d containing corn or soybean oil, matched with the active treatment for taste and color | 112 d |
Behavioral and medical sleep problems were measured by CSHQ. TSD, SL, SEff, frequency and length of wakefulness during night were measured by sleep diary and actigraphy. |
Slight but nonsignificant improvements were seen in both groups for all but 1 CSHQ subscale (sleep duration). Actigraphy results showed TSD increased by 58 min more in the active group than in the control group. TSD (h): I: 3.94 ± 1.214, C: 3.88 ± 1.202, z = −0.724, P = 0.469. Sleep onset delay: I : 1.66 ± 0.676, C: 1.62 ± 0.677, z = 0.71, P = 0.478. Bedtime resistance: I : 6.99 ± 1.575, C: 7.33 ± 2.02, z = 0.998, P = 0.318. Daytime sleepiness: I: 9.56 ± 2.555, C: 9.69 ± 2.766, z = −0.128, P = 0.898. TSD: I : 40.48 ± 6.166, C: 40.87 ± 6.084, z = −0.682, P = 0.495. Actigraphy score: TSD (min): I: 639 ± 52, C: 611 ± 66, t = 0.6, P = 0.551. SEff (ratio): I: 0.8 ± 0.098, C: 0.09 ± 0.117, t = 2.000, P = 0.052. Wake episodes: I: 12.86 ± 3.93, C: 15.78 ± 6.521, t = −2.59, P = 0.013. SL (min): I: 14 ± 22, C : 25 ± 33, z = 0379, P = 0.704. |
| 5 | Yehuda et al, (2011)57 | Israel | CT | Children aged 9–12 y (n = 78) and diagnosed with ADHD with onset of sleep deprivation | Capsules containing 720 g/d linoleic acid and 180 g/d ALA. | Placebo composed of mineral oil in identical capsule. Two capsules/d | 70 d | Self-reported SQ measured on a 5-point Likert-scale question | SQ: I: 3.8 ± 0.7, C: 1.4 ± 0.8. Polyunsaturated acid administration was associated with significant improvement in quality of life, ability to concentrate, SQ, and hemoglobin levels. |
| Adults (aged > 18 y) | |||||||||
| 6 | Yehuda et al (2005)19 | Israel | RCT | Undergraduate male students (n = 126) with test anxiety | Two capsules/d containing 450 mg of ALA and linoleic acid in a 1:4 ratio | Mineral oil | 21 d | Self-reported SQ on a 5-point Likert-scale question | Participants in the intervention group reported better sleep than those who received placebo. SQ: I: 3.6 ± 1.0, C: 1.8 ± 1.1. |
| 7 | Dretsch et al (2014)47 | United States | RCT | US deployed soldiers aged 18–55 y (n = 106) | One capsule/d containing 2500 mg EPA+DHA | Identical corn oil capsules containing 12% palmitic acid, 28% oleic acid, and 56% linoleic acid | 60 d | Self-reported SQ was measured by PSQI. Daytime sleepiness was measured by ESS. | PSQI score: I: 7.1 ± 3.4, C: 7.1 ± 3.7, effect sizes (Cohen d = 0.10), P = 0.663; ESS score I: 10.7 ± 4.5, C: 10.0 ± 4.3, Cohen d = 0.26, P = 0.247. A change in the HS-Omega-3 Index was a significant predictor of the change in ESS scores, F(1, 77) = 7.25, P = 0.009, suggesting that as omega-3 levels increased, daytime sleepiness decreased. |
| 8 | Hansen et al (2014)48 | United States | RCT | Male forensic patients aged 21–60 years (n = 95) from a secure forensic inpatient facility in the USA | 300 gram of Atlantic salmon that contain 4.8 g of EPA+DHA was served three times a week; however during the final 4 wk of the study, only 150 g of salmon were served each time. | Meat (eg, chicken, pork, beef) meals three times a week | 180 d | SL, SE, TSD, and actual wake time were measured by actigraph. Self-reported SQ was measured by sleep diary. | Actigraph: SL (min): I: 23.30 ± 20.38, C: 30.89 ± 18.93, main effects between two groups: F = 0.198, P = 0.66; effects between pre- and post-test conditions: F = 4.14, P = 0.05; interaction between groups and conditions: F = 4.11, P = 0.05. SEff (min): I: 70.37 ± 10.33, C: 69.64 ± 7.1, effect between groups: not significant; main effects of pre- and post-conditions: F = 32.84, P < 0.001; interaction between groups and conditions: F = 1.63, P = 0.21. Actual wake time (min): I: 110.04 ± 59.09, C: 107.49 ± 31.1, with a significant effect of pre- and post-test conditions (F = 19.83, P < 0.001), and a significant increase in actual wake time from pre- to post-test (P < 0.001, d = 0.43). TSD (min): I: 328.78 ± 52.84, C: 325.53 ± 67.09; main effect of pre- and post-test conditions: F = 7.44, P = 0.008. Self-reported SQ: 3.52 ± 0.6, C: 3.41 ± 0.8, with no effect of groups (F = 0.20, P = 0.66); no effect of pre- and post-test conditions (F = 0.26, P = 0.61). Daily functioning score: I: 3.35 ± 0.86, C: 2.85 ± 0.62, with significant main effect of groups, F = 54.63, P = 0.03, no effects of the pre- and post-test conditions (F = 0.49, P = 0.49). |
| 9 | Watanabe et al (2018)55 | Japan | RCT | Female nurses aged 20–59 y (n = 80) and worked in inpatient wards at hospitals | Omega-3 PUFA capsules containing 1200 mg EPA and 60 mg DHA per day | Identical capsules contained rapeseed oil (47%), soybean oil (25%), olive oil (25%), and fish oil (3%) | 91 d of capsule intake and 52 wk of follow-up | Insomnia severity was measured by ISI | ISI score at the week 52: I: 6.07 (95%CI, 4.96–7.18), C: 5.34 (95%CI, 4.16–6.51), group by time interaction, −0.24 (95%CI, −1.96 to 1.49), P = 0.786. Statistically significant superiority was observed in favor of the omega-3 PUFA group in terms of the ISI at 13 wk (95%CI, −6.29 to −12.56, and 0.02; P = 0.049), but no significant differences were found in other time periods. |
| 10 | Doornbos et al (2009)51 | Netherlands | RCT | Healthy pregnant women (n = 119) | DHA 220 mg or DHA+AA 220 mg/d | Soybean oil | From second trimester to 3 wk after delivery | Quantity and quality of sleep were assessed using sleep diaries. | No between-group effects were noted. The indices of SQ did not change significantly over time in any group. In a significant regression model, F = 15.240; P < 0.001. Efficient sleep at week 4 postpartum (min) median (25th;75th percentile): I: 487 ( 420–540), C = 450 ( 370, 490), SEff (%) median (25th;75th percentile): I: 88.03 ( 81.28–90.39), C: 84.62 ( 78.22–87.50), P > 0.05 for all. |
| 11 | Judge et al (2014)49 | United States | RCT (pilot trial) | Pregnant women aged 18–35 years (n = 42) without self-reported significant medical history | One fish oil capsule that contains 300 mg DHA, 5 d weekly | Corn oil | From 24 wk gestation to delivery | Sleep disturbance was measured with a 5-point Likert item contained in the postpartum depressive symptomatology. | Sleep disturbance at 6 mo (mean ± SD): I: 6.80 ± 3.44, C: 7.00 ± 2.67, > 0.05. |
| 12 | Cohen et al (2014)44 and Reed et al (2014)45 were the same study | United States | RCT | Women aged 40–62 y (n = 355) experiencing the menopausal or postmenopausal transition | Fish oil capsule containing a total omega-3 dose of 615 mg, including EPA 425 mg and DHA 100 mg, along with other assorted omega-3 PUFA (90 mg) | Matching placebo capsule containing olive oil | 84 d | Self-reported SQ was measured by PSQI. Insomnia severity was measured by ISI. | The mean PSQI score reduction was 2.1 for the omega-3 group and 1.7 for the placebo group (P = 0.09). The mean ISI reduction was 3.8 for the omega-3 group and 3.7 for the placebo group (P = 0.73). |
a
Time in bed was calculated by subtracting bedtime from rise time.
Abbreviations: AA, arachidonic acid; ADHD, attention deficit hyperactivity disorder; ALA, α-linolenic acid; AS, active sleep; BISQ, Brief Infant Sleep Questionnaire; C, control group; CSHQ, Children’s Sleep Habits Questionnaire; CT, controlled trial; DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; ESS, Epworth Sleepiness Scale; I, intervention group; ISI, Insomnia Severity Index; PSQI, Pittsburgh Sleep Quality Index; PUFA, polyunsaturated fatty acid; QS, quiet sleep; RCT, randomized controlled trial; SEff, sleep efficiency; SL, sleep latency; SQ, sleep quality; TSD, total sleep duration.