Effect of gut microbiota modulation on sleep: a systematic review and meta-analysis of clinical trials

1 ABSTRACT 1 Con ex : A bidi ec ional ela ionship be ween gu mic obio a (GM) and ci cadian 2 hy hms has been p oposed. Objec i e: The aim o his s udy was o analyse he e icacy 3 o p obio ic o p ebio ic in e en ion on sleep quali y and quan i y. Da a sou ces, 4 selec ion and ex ac ion: A sys ema ic e iew and me a-analysis we e conduc ed using 5 he da abases PubMed-Medline, Embase, CINAHL and Web o Science. Only 6 andomised clinical ials w i en in English o Spanish we e conside ed. The ini ial 7 sea ch esul ed in 219 a icles. Following he emo al o duplica es and conside a ion o 8 he selec ion c i e ia, 25 a icles we e selec ed o he sys ema ic e iew and 18 a icles 9 o he me a-analysis. Resul s: The e ec o mic obio a modula ion showed no 10 signi ican imp o emen on sleep quali y in ou me a-analysis (p=0.31). In e ms o sleep 11 du a ion, he me a-analysis ound no imp o emen due o GM modula ion (p=0.43). 12 Conclusions: Ou me a-analysis esul s indica e ha he e is s ill insu icien e idence o 13 suppo he ela ionship be ween GM modula ion and imp o ed sleep quali y. While 14 se e al s udies assume ha including p obio ics in he die will undoub edly imp o e 15 sleep quali y, mo e esea ch is needed o ully unde s and his phenomenom. Sys ema ic 16 Re iew Regis a ion: PROSPERO egis a ion no. CRD42021245118. 17 18 2 INTRODUCTION 19 Gu mic obio a (GM) e e s o he se o mo e han 1000 species o li ing mic oo ganisms 20 such as i uses, bac e ia, a chaea, ungi and p o is s ha colonise he gas oin es inal 21 ac .1 The GM cons i u es a hos -speci ic ecosys em ha is gene ically inhe i ed and 22 ma u es du ing childhood, a ec ing indi iduals’ physiological homeos asis.2 The 23 unc ions o GM include con olling he p oli e a ion o pa hogenic bac e ia, egula ing 24 nu ien abso p ion and me abolism, modula ing he immune sys em and pa icipa ing in 25 he syn hesis o me aboli es such as sho -chain a y acids (SCFA) and i amins ha 26 p o ide bene i s o he hos .3–6 27 GM composi ion depends on se e al ac o s such as die , inges ion o ce ain d ugs, age 28 and gene ics, bu in gene al he dominan mic obial communi ies a e he phyla 29 Fi micu es, Bac e oide es, Ac inobac e ia and P o eobac e ia.7 Ce ain ac o s can a ec 30 he di e si y o GM leading o a p ocess known as in es inal dysbiosis.8,9 I has been 31 p oposed ha he phenomenon o dysbiosis could be ela ed o he de elopmen o 32 diso de s, such as obesi y and au ism, h ough wha is known as he gu -b ain axis 33 (GBA).10–12 The gu has an in insic inne a ion, he en e ic ne ous sys em (ENS), 34 composed o senso y neu ons ha de ec physicochemical changes, mo o neu ons and 35 in e neu ons loca ed in en e ic ganglia o ming a complex ne wo k o mo e han 500 36 million neu ons.13 In succession, he ne ous cells o he ENS can communica e wi h 37 b ain neu ons and GM ia GBA. This communica ion sys em is bidi ec ional and is 38 ca ied ou in h ee main pa hways: he agus ne e, he sys emic ci cula ion and he 39 immune sys em in ol ing neu o ansmi e s and neu omodula o s.13 40 3 Due o he bidi ec ional ela ionship be ween he cen al ne ous sys em (CNS) and GM, 41 se e al s udies ha e associa ed sleep dis u bances wi h changes in GM composi ion, as 42 hey obse ed ha pa ien s wi h insomnia had lowe mic obial ichness and di e si y 43 caused by a deple ion o anae obic bac e ia and SCFA-p oducing bac e ia ela ed o 44 con ol indi iduals.14,15 Lachnospi a and Bac e oides, in pa icula , a e common bac e ia 45 in pa ien s wi h acu e insomnia, whe eas Faecalibac e ium and Blau ia a e equen in 46 pa ien s wi h ch onic insomnia.14 47 Rega ding sleep, i is wo h no ing ha i plays a key ole in de elopmen , g ow h and 48 immune unc ion. Insu icien sleep has been associa ed wi h an inc eased isk o 49 mo ali y and he de elopmen o ca dio ascula and co ona y hea disease, hype ension 50 and diabe es.16 Addi ionally, i has been p oposed ha sleep quali y dis u bances may be 51 d i en by hypo halamic-pi ui a y-ad enal (HPA) axis o e ac i i y and co isol 52 hype sec e ion.17 The bene icial e ec s o GM on he CNS ia he GBA ha e led some 53 esea che s o sugges ha GM in e ac s wi h he ci cadian sys em, as he gu in luences 54 ene gy s a us by con olling physiological unc ions such as diges ion and nu ien 55 abso p ion, unc ions ha a e also egula ed by he gene ic clock. 56 The use o p obio ics and p ebio ics o manage in es inal dysbiosis ha e been es ed in 57 humans. Fo example, he adminis a ion o p obio ics con aining li e mic oo ganisms 58 showed bene icial e ec s on pa hologies such as dia hoea, coli is, and in lamma o y 59 bowel disease.18,19 P ebio ics p omo e he selec i e g ow h o bac e ia by p e en ing he 60 g ow h o pa hogens in he colonic lo a. The ood componen s ha seem o exe he bes 61 p ebio ic e ec a e uc ooligosaccha ides (FOS), inulin and lac ulose.20,21 In ecen 62 yea s, he adminis a ion o p ebio ics and p obio ics has been in es iga ed wi h he aim 63 o ea ing insomnia in bo h expe imen al animals and humans, al hough con adic o y 64 4 da a ha e been ound.22 Fo example, he adminis a ion o Lac obacillus b e is DL1-11, 65 L. b e is SBC8803 and L. e men um PS150TM was able o inc ease sleep du a ion and 66 dec ease sleep la ency in mice.23–25 Simila ly, ea men s wi h Lac obacillus gasse i 67 CP2305 and Lac obacillus casei s ain Shi o a (LcS) imp o ed sleep quali y in heal hy 68 adul s a ec ed by s ess.26,27 Howe e , ano he s udy ound no changes in sleep quali y 69 a e adminis a ion o Lac obacillus acidophilus Rosell-52 and Bi idobac e ium 70 longum Rosell-175 in s ess-a ec ed olun ee s.28 Rega ding p ebio ics such as inulin o 71 galac o-oligosaccha ides (GOS), i seems ha hey ha e no e ec on sleep dis u bances 72 ei he in adul s o in child en.29,30 73 The main hypo hesis p oposed in ela ion o he seda i e e ec o some p obio ic s ains 74 is associa ed o he immune sys em modula ion. The p oduc ion o p o-in lamma o y 75 cy okines such as in e leukin 1-be a (IL-1β) and umou nec osis ac o alpha (TNF-α) 76 has been ound o be inc eased in a s exposed o ch onic sleep es ic ion, indica ing he 77 p esence o in lamma o y p ocesses in sleep- es ic ed expe imen al animals.31 In his 78 ega d, he e is e idence o an i-in lamma o y e ec s o p obio ic s ains such as 79 Lac obacillus plan a um, which hinde s he exp ession o IL-1β and TNF-α while 80 inc easing he exp ession o IL-10, an an i-in lamma o y cy okine, in a s ea ed wi h 81 2,4,6- ini obenzenesul onic acid (TNBS)-induced coli is.32 82 To da e, e idence o he e ec o p obio ics on sleep quali y is e y limi ed,33,34 bu no 83 e idence has been ound o o he modula o s o GM, such as p ebio ics o FMT. Thus, 84 he o e all aim o his e iew was o analyse how GM in e en ion by p obio ics o 85 p ebio ics a ec s sleep quali y and quan i y, wi h o he ac o s such as sleep du a ion as 86 seconda y objec i es. 87 5 METHODS 88 A sys ema ic e iew was conduc ed wi h s udies un il Sep embe 2022 ollowing he 89 P e e ed Repo ing I ems o Sys ema ic e iews and Me a-Analyses (PRISMA) 90 guidelines35 (Table S1) and he Coch ane sys ema ic e iew manual.36 The p o ocol o 91 his s udy was egis e ed in PROSPERO (CRD42021245118). 92 Da abases 93 The esea ch ques ion used in he sea ch o in o ma ion wi hin his e iew ollowed he 94 Pa ien -In e en ion-Ou comes (PIO) s uc u e (Table 1): “How does GM modula ion 95 in luence sleep quali y?”, as a consequence o he unc ion o he in es inal mic obio a 96 like an an i-in lamma o y and neu op o ec i e agen o he cen al ne ous sys em ha 97 in e ac s wi h he ci cadian sys em. 98 [INSERT TABLE 1 AROUND HERE] 99 Fou da abases we e used o collec da a (PubMed-Medline, CINAHL, Embase and Web 100 o Science), and sea ch s a egies we e de eloped by combining s uc u ed language 101 (Medical Subjec Heading) and na u al language. The s a egies adap ed o each da abase 102 a e shown in Table S2. 103 S udy eligibili y c i e ia 104 The inclusion c i e ia used o his e iew we e as ollows: andomised clinical ials 105 (RCTs) pe o med in humans, published in Spanish o English, and ele an o he aim o 106 he s udy, including a measu e o sleep quali y and du a ion. Re iews, con e ence 107 abs ac s, quali a i e s udies, o desc ip i e o obse a ional s udies wi hou a con ol 108 6 g oup we e excluded. Simila ly, s udies conduc ed on he paedia ic popula ion we e 109 disca ded. No s udies we e excluded due o me hodological laws o age es ic ions. 110 Selec ion o s udies and me hodological quali y 111 Two au ho s (EGH and CRG) ca ied ou he a icle selec ion p ocess independen ly; in 112 case o disc epancy, a hi d esea che (PR) was consul ed. Likewise, he me hodological 113 quali y was e alua ed using he Jadad scale o andomised clinical ials. This scale is 114 composed o 5 i ems ha se e o e alua e he quali y o RCTs in a simple manne .37 A 115 sco e o mo e han 3 poin s is associa ed wi h a high-quali y s udy, while a sco e o less 116 han 3 poin s is associa ed wi h a low-quali y s udy; hese sco es a e based on he quali y 117 o double blinding, andomiza ion and ollow-up.38 I should be no ed ha his scale 118 co e s some o he elemen s ela ed o biases, hus acqui ing eliabili y and ex e nal 119 alidi y.39 120 Da a ex ac ion 121 Da a we e ex ac ed independen ly by wo in es iga o s (EGH and CRG) om each o 122 he s udies and abula ed as ollows: (1) e e ence; (2) numbe o pa icipan s; (3) 123 in e en ion used; (4) du a ion o in e en ion; (5) a iables analyzed; and (6) main 124 ou comes. 125 The WebPlo Digi ize p og am was used o ob ain he da a om hose a icles ha 126 p o ided only he ele an esul s in g aphs. This so wa e has al eady been used by o he 127 au ho s in me a-analyses, demons a ing i s e ec i eness in ex ac ing da a om 128 g aphs.40,41 129 S a is ical analysis 130 7 The me a-analysis o he included ials was pe o med using Re iew Manage (Re Man) 131 so wa e e sion 5.4. 132 E ec size 133 The e ec size was measu ed by he mean di e ence and s anda d de ia ion o s anda d 134 e o be ween he con ol and expe imen al g oups. 135 Fo he main a iable, sleep quali y, he ollowing ques ionnai es we e used: Pi sbu gh 136 Sleep Quali y Ques ionnai e (PSQI), Nume ic Ra ing Scale (NRS) and A hens Insomnia 137 Scale (AIS). 138 The s udies included in he me a-analysis had o p o ide da a on means, s anda d 139 de ia ion o s anda d e o ; o could be calcula ed om o he da a p o ided. O he wise, 140 he co esponding au ho was con ac ed and, i no esponse was ecei ed, hey we e 141 disca ded om he me a-analysis. 142 He e ogenei y and publica ion bias 143 Depending on he deg ee o he e ogenei y (I2) ob ained, a andom-e ec s model (I2≥50%) 144 o a ixed-e ec s model (I2 ≤50%) was used o pe o m he me a-analysis. A o es plo 145 ep esen ed he analysis. In addi ion, he p- alue was conside ed signi ican when i was 146 <0.05. 147 A sensi i i y analysis was also used o obse e whe he changes in he da a o in he 148 objec i e o he analysis a ec ed he esul s and conclusions o his e iew. I a e 149 sensi i i y analysis, he conclusions did no change, hey we e conside ed obus . Fo his 150 8 pu pose, each o he s udies was excluded independen ly o iden i y which o hem had a 151 signi ican in luence on he indings. 152 RESULTS 153 A e sea ching he di e en da abases, 219 a icles we e ini ially e ie ed. One hunded 154 i y-one a icles we e sc eened by eading hei i le and abs ac a e emo ing 155 duplica es (68 documen s). The numbe o publica ions conside ed in his sys ema ic 156 e iew was educed o 25 a e ull- ex analysis, wi h 18 ials included in he me a-157 analysis. The en i e p ocess is depic ed in Figu e 1. 158 [INSERT FIGURE 1 AROUND HERE] 159 Included s udies 160 The s udy popula ion included a highe p opo ion o heal hy people and s uden s (60%). 161 O e all, he s udies inco po a ed a o al o 2192 pa icipan s, wi h a mean o 91.33 162 indi iduals (max= 581, min= 10) and a mean in e en ion du a ion o 7.12 weeks (max= 163 24, min=1). 164 Mos s udies used p obio ics as modula o s o GM. The mos -used p obio ic species we e 165 Lac obacillus and Bi idobac e ium, hough Saccha omyces ce e isiae, S ep ococcus and 166 En e ococcus aecalis we e also used, as we e h ee ypes o p ebio ics (Inulin, GOS and 167 FOS). Di e en s ains o Lac obacillus (acidophilus, bulga is, hamnosus, casei, 168 plan a um, e men um, delb ueckii ssp. Bulga icus, eu e i, gasse i, casei Shi o a, 169 hel e icus) and o Bi idobac e ium (animalis ssp. lac is, longum, adolescen is, b e e, 170 bi idum, longum ssp. in an is) we e used in he assays. Only one s udy used p ebio ics, 171 p ima ily inulin and uc o-oligosaccha ides, as GM modi ie s. Fu he mo e, s udies ha 172 9 used synbio ics in he in e en ion g oup we e included. Lac obacillus and 173 Bi idobac e ium s ains we e used as p obio ics, and inulin and FOS we e used as 174 p ebio ics. 175 Sleep quali y was analysed in 88.46% o he selec ed s udies, while sleep du a ion was 176 analysed in 30.77%. The esul s ex ac ed om he RCTs, as well as hei cha ac e is ics, 177 a e shown in Table 2. 178 [INSERT TABLE 2 AROUND HERE] 179 Me hodological quali y: assessmen o bias 180 Figu e 2 shows he o e all sco e o each i em, wi h he lowes isk o bias in s udies ha 181 included andomisa ion and a desc ip ion o pa icipan blinding. Howe e , he ials did 182 no usually s a e how his andomisa ion and blinding we e pe o med, no whe he he 183 a e o he pa icipan s was known. On he o he hand, Figu e 3 shows he e alua ion o 184 he me hodological quali y and isk o bias using he Jadad scale o he s udies included 185 in he sys ema ic e iew. Wi h he excep ion o he s udies by Lee e al. (2021), Que o e 186 al. (2021), Rode e al. (2022), Sha ie e al. (2022), Valle e al. (2021), Wäli aa a e al. 187 (2019) and Wang e al. (2021), whose me hodological quali y is qui e high, his igu e 188 shows ha some s udies ha e i ems wi h some de iciencies.26–29,42–62,52,59,60 189 [INSERT FIGURE 2 AND 3 AROUND HERE] 190 Sleep quali y and du a ion 191 T ea ing heal hy s uden s, we ound se e al a icles.26,27,43,45,49,51,56,63 All o hem used 192 p obio ics as he in e en ion in hei expe imen al g oups, mos ly using Lac obacillus as 193 16 In e es ingly, ecen indings sugges ha immune sys em cells can in luence GBA since 327 an in lamma o y en i onmen in he in es inal mucosa can inc ease pe meabili y and hus 328 impac b ain ac i i y78, as some cy okines ha e been shown o c oss he blood b ain 329 ba ie (BBB) and p omo e neu oin lamma ion.79 In e ms o immune sys em s a us, 330 Wang e al. (2021) concluded ha a combina ion o p obio ic s ains including 331 Bi idobac e ium longum, Lac obacillus acidophilus, and En e ococcus aecalis we e able 332 o educe plasma IL-6 le els in olde adul s on he 5 h-7 h day pos -su ge y 44. This e ec 333 on IL-6 was also shown in imma u e en e ocy es u ilising p obio ic condi ioned media 334 (PCM) om Bi idobac e ium longum subsp in an is and Lac obacillus acidophilus, bu 335 no isola ed o ganisms, which a enua ed and dec eased IL-6 induced by IL-1.80,81 336 Con e sely, IL-1Ra, IL-10, IL-1b, IL-6, IL-8, and TNF-α concen a ions did no al e 337 a e adminis a ion o Lac obacillus acidophilus (DDS-1), Bi idobac e ium animalis spp. 338 lac is (UABla-12) and L. hamnosus (JB-1) o he in e en ion g oup.50,60 In his con ex , 339 L. hamnosus GG (LGG) has no been demons a ed o change IL-10 le els, bu has been 340 epo ed o inc ease IL-10R2 ecep o subuni exp ession and dec ease TNF- exp ession 341 in he mouse colon.82 Ano he s udy ound ha LGG-condi ioned medium educed TNF- 342 p oduc ion in LPS-ac i a ed mac ophages.83 343 Co isol is well known o in luence he sleep quali y and du a ion, as high le els inc ease 344 waking ime and lack o sleep inc eases co isol le els.84 The e ec o p obio ic 345 supplemen a ion on sali a y and plasma co isol le els has yielded con adic o y esul s. 346 In only h ee o he ials included in his s udy, blood and sali a y co isol le els we e 347 al e ed a e adminis a ion o Bi idobac e ium, Lac obacillus, and En e ococcus 348 s ains.44,49,60 In his manne , p obio ic supplemen a ion has been documen ed in ce ain 349 ials o signi ican ly educe plasma co isol le els in s essed-ou s uden s and adul s.85,86 350 17 In he o he ials e alua ed, p obio ics ailed o lowe co isol le els.27,43,50,63 This is 351 consis en wi h a cu en clinical ial in which Bi idobac e ium b e e CCFM1025 was 352 adminis e ed o pa ien s wi h majo dep ession, ye ailed o lowe se um co isol le els.87 353 Nume ous s udies on mic obio a-de i ed me aboli es ha e sugges ed ha low SCFA 354 concen a ions may con ibu e o he de elopmen o neu opsychia ic diseases, obesi y, 355 and au ism.88–90 Addi ionally, g ea e aecal p opionic acid le els in in an s a e associa ed 356 wi h longe pe iods o unin e up ed sleep.91 These indings show ha consuming 357 p obio ic s ains de i ed om SCFA-p oducing bac e ia could be an a ac i e s a egy. 358 Only Nishida e al. (2019) s udied he impac s o p obio ic consump ion on SCFAs, 359 concluding ha Lac obacillus gasse i p obio ic supplemen a ion inc eased n- ale ic 360 le els in heal hy olun ee s bu did no a ec o he SCFAs such as p opionic and ace ic 361 acids.27 Simila , esea ch using Bi idobac e ium animalis subsp. lac is BB-12 (BB-12) 362 ound ha i did no signi ican ly enhance aecal SCFA le els in heal hy adul s.92,93 363 Limi a ions 364 The numbe o s udies included in he me a-analysis is limi ed owing o lack o da a se s 365 equi ed o p ocess and comple e he analysis. While we a emp ed o con ac all 366 co esponding au ho s o s udies ha did no con ain his in o ma ion, we did no always 367 ecei e a esponse. As a esul , ou s udies mus be excluded om he me a-analysis and 368 he sys ema ic e iew.42,46,49,51 Ano he limi a ion o conside when in e p e ing he 369 esul s o his me a-analysis is he la ge a iabili y in in e en ion leng h, which anges 370 om 1 week in he s udy by Wang e al. (2021) o 24 weeks in he s udy by Nishida e al. 371 (2019), he e o e his he e ogenei y may ha e an impac on he analysis and he 372 magni ude o ou comes be ween in e en ions may no be accu a ely examined. 373 18 Rega ding he adminis a ion o p ebio ics, only one RCT was i ed in he inclusion 374 c i e ia, he e o e we canno d aw a p ecise conclusion abou he in luence o p ebio ics 375 on sleep. Ano he aspec o conside when in e p e ing and analysing he esul s is ha a 376 signi ican p opo ion o he included s udies used sel - epo scales o assess sleep 377 quali y. In addi ion o hese alida ed scales95-97, i would ha e been in e es ing o include 378 objec i e measu es o sleep quali y, wi h he PSQI being he mos commonly used in he 379 s udies selec ed. Finally, since i was ou side he scope o his manusc ip , he esponse 380 o he gu mic obiome o p obio ic o p ebio ic in e en ion was no assessed in his 381 sys ema ic e iew and me a-analysis, and hus he e ec o mic obiome modula ion om 382 he in e en ions could no be de e mined. Ra he han concluding he issue, ou indings 383 pa e way o u u e esea ch o de e mine which in e en ions a e associa ed wi h a 384 measu able gu mic obiome esponse and whe he his co ela es wi h changes in sleep 385 quali y. Likewise, u u e clinical ials should conside de ailing he blinding me hods and 386 pa icipan d opou a e in o de o imp o e igou and ep oducibili y, as hese i ems ank 387 lowes in ou quali y assessmen o included s udies. 388 CONCLUSIONS 389 Al hough se e al s udies ag ee ha modula ion o he mic obio a a ec s sleep quali y, 390 he esul s o ou me a-analysis do no show ha he implemen a ion o p obio ics in he 391 die leads o a signi ican imp o emen in sleep quali y. The as majo i y o he bac e ia 392 used in he s udies included in his s udy we e om he Lac obacillus and Bi idobac e ium 393 amilies, while En e ococcus aecalis, S ep ococcus he mophilus, and Saccha omyces 394 ce e isiae we e also used. 395 19 Few s udies p o ided su icien da a o be included in ou me a-analysis in e ms o sleep 396 du a ion, which did no include s a is ically signi ican da a. Because o his, i would be 397 in e es ing o expand esea ch in his a ea o ha e access o a la ge amoun o da a and 398 he e o e be able o ob ain a mo e exhaus i e and p ecise conclusion. Only one clinical 399 ial wi h p ebio ics was included in his s udy, which used Inulin and FOS in i s 400 expe imen al g oup. Due o limi ed a ailabili y o s udies ob ained du ing ou sea ch, we 401 a e unable o d aw any conclusions on he e ec s o including p ebio ics in he die ; 402 hence, i would also be wo h conduc ing addi ional esea ch in his a ea. 403 ACKNOWLEDGMENTS 404 The CTS-451 Resea ch G oup and he CEINSA Resea ch Cen e ha e suppo ed his 405 esea ch. 406 Funding. This esea ch ecei ed no speci ic g an om any unding agency in he public, 407 comme cial, o no - o -p o i sec o s. 408 Decla a ions o in e es . The au ho s ha e no ele an in e es s o decla e. 409 SUPPORTING INFORMATION 410 Table S1: PRISMA checklis . 411 Table S2: Sea ch s a egies in each da abase used. 412 REFERENCES 413 1. Ma ijašić M, Meš o ić T, Palje ak HČ, Pe ić M, Ba ešić A, Ve banac D. Gu 414 mic obio a beyond bac e ia—mycobiome, i ome, a chaeome, and euka yo ic 415 20 pa asi es in IBD. In J Mol Sci. 2020;21(8). doi:10.3390/ijms21082668 416 2. De ien M, Al a ez AS, de Vos WM. 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Lee Y, Ba Z, Robe s RF, e al. E ec s o Bi idobac e ium animalis subsp. lac is 728 BB-12® on he lipid/lipop o ein p o ile and sho chain a y acids in heal hy 729 young adul s: a andomized con olled ial. Nu J. 2017;16(1):1-9. 730 doi:10.1186/s12937-017-0261-6 731 732 733 35 Table Legend 734 Table 1. PIO c i e ia 735 Table 2. Summa y o ials selec ed o e iew 736 Figu e Legend 737 Figu e 1. Flowcha 738 Figu e 1. G aph o he me hodological quali y o he ials included in he s udy. 739 Figu e 2. Me hodological quali y o included clinical ials (n=25). 740 Figu e 4. Fo es plo showing he e ec s o GM modula ion on he quali y o sleep (n=18). 741 Figu e 5. Fo es plo e lec ing he e ec s o GM modula ion on sleep du a ion (n=5). 742 743 36 Table 1. PIO c i e ia 744 RCT: Randomized clinical ial 745 746 747 748 Pa ame e C i e ia Popula ion Adolescen and adul popula ion (olde han 18 yea s old) In e en ion P obio ics and p ebio ics o mula ions Ou comes Quali y and du a ion o sleep S udy design RCT Language Spanish o English 37 Table 2. Summa y o ials selec ed o e iew 749 REFERENCE N INTERVENTION USED INTERVENTION DURATION (WEEKS) VARIABLES ANALYZED DATA COLLECTION TOOLS MAIN RESULTS PROBIOTIC Rode e al. (2022)57 Heal hy subjec s aged 20-28 (n=22) Lac obacillus hel e icus R0052 (2×109 CFU), Lac iplan ibacillus plan a um R1012 (8 × 108 CFU) and Bi idobac e ium longum R0175 (7×107 CFU) Powde sache 4 Anxie y S ess Dep ession Sleep quali y Sleepiness Awakening HADS PSS STAI KSD The e we e no signi ican di e ences in sleep quali y be ween he p obio ic in e en ion and he placebo g oup Sha ie e al (2022)58 Pos menopausal women aged 45-55 (n=66) Lac obacillus bulga icus, S ep ococcus he mophilus Bi idobac e ium lac is and L. acidophilus Yogu 6 Anxie y S ess Dep ession Sleep quali y PSQI DASS-21 The use o p obio ics had no e ec on sleep quali y Da oodabadi e al (2021)59 Females aged 18-40 su e ed om cyclical mas algia due o b eas FCC (n=45) Lac obacillus acidophilus, L. e men um, L. eu e i, and Bi idiobac e ium bi idum 2x109 CFU Capsule 12 Dep ession Anxie y Sleep quali y BDI BAI PSQI The p obio ic g oup did no imp o e sleep quali y Wes e al (2021)60 Nigh shi wo ke s (n=87) Lac obacillus acidophilus DDS-1 and Bi idobac e ium animalis spp. lac is UABla-12. 1x1010 CFU Capsule 2 Sleep quali y PSQI Fi bi sleep ime (min) Signi ican changes in sleep quali y in he expe imen al g oups Calga o e al. (2021)61 Heal hy subjec s (n=33) Limosil ac obacillus e men um LF16 (DSM 26956), Lac icaseibacillus hamnosus LR06 (DSM 21981), Lac iplan ibacillus plan a um LP01 (LMG P-21021), and Bi idobac e im longum 04 (DSM 23233). 4×109 CFU/AFU. Sache 6 Sleep quali y PSQI Signi ican imp o emen in sleep quali y Lee e al (2021)62 Heal hy adul s aged 19-65 (n=156) Lac obacillus eu e i NK33 and Bi idobac e im adolescen is NK98 2.5 × 109 CFU/500 mg Capsule 8 Sleep quali y Symp oms o insomnia Mood BAI BDI-2 PSQI ISI SRI Signi ican educ ions in sleep quali y and se e i y o insomnia in he expe imen al g oup 38 Ha ne e al (2021)42 Eli e a hle es (n=38) Ul abio ic 60TMi and SBFlo ac i TMii Table 17 Sleeping hou s Sleep quali y Sel - epo ed sleep quali y Sel - epo ed numbe o hou s o sleep Sleep quali y and quan i y imp o ed in he expe imen al g oup Moloney e al (2021)43 S uden s aged 18-40 (n=20) Bi idobac e ium longum AH1714. 1x109 CFU Capsule 8 Dep ession measu emen s Sleep quali y Mood PSS HADS-A, HADS-D PSQI The p obio ic Bi idobac e ium longum imp o ed sleep quali y and du a ion in he expe imen al g oup Wang e al (2021)44 Olde adul s (n=120) Bi idobac e ium longum Lac obacillus acidophilus En e ococcus aecalis Mo e o 1.0x107 CFU/g. Capsule 1 Pos ope a i e cogni i e impai men Pos ope a i e sleep quali y MMSE NRS No signi ican di e ences we e ound in sleep quali y be ween he expe imen al and con ol g oup Ma o a e al (2019)45 Heal hy s uden s (n=38) Lac obacillus e men um LF16 (DSM 26956) L. hamnosus LR06 (DSM 21981) L. plan a um LP01 (LMG P-21021) Bi idobac e ium longum BL04 (DSM 23233) 4x109 CFU Powde 9 P esence and se e i y o anxie y symp oms and p opensi y o be anxious Occu ence and se e i y o dep essi e symp oms Mood Sleep quali y LEIDS-R STAI BDI-2 POMS PSQI An inc ease in sleep quali y was obse ed in he expe imen al g oup Wäli aa a e al (2019)46 Heal hy pa ien s (n=61) Lac obacillus eu e i (DSM 17938 and ATCC PTA 5289). 2x108 li e bac e ia om he combined s ains Table 2 Sleep Sel - epo ed da a on dis u bed sleep The expe imen al g oup was associa ed wi h ewe nigh s o in e up ed sleep Nishida e al (2019)27 Heal hy s uden s (n=60) Lac obacillus gasse i CP2305. 1x1010 bac e ial cells pe 2 able s Table 24 Men al and physical condi ion Sleep quali y STAI GHQ-28 HADS PSQI In ake o he p obio ic signi ican ly educed sleep diso de s Lei e al (2018)47 Pa ien s wi h simple ib ac u e (n=283) Lac obacillus casei Shi o a. 6x109 CFU Milk 4 Sleep quali y NRS The e was no signi ican imp o emen in sleep quali y Nishida e al (2017)63 S uden s aged 18-34 (n=32) Lac obacillus gasse i CP2305. 1x1010 CFU Canned milk 5 Men al and physical condi ion Sleep measu emen and assessmen GHQ-28 Zung-SDS HADS STAI PSQI Sleep quali y imp o ed in he p obio ic g oup, sho ened sleep la ency, and inc eased sleep du a ion 39 Sawada e al (2017)49 S uden s (n.d.) Lac obacillus gasse i CP2305. 1.0x1010 CFU Powde 4 Men al heal h Sleep quali y and dis u bances GHQ-28 Zungs-SDS HADS STAI PSQI P obio ic inges ion p e en ed he de elopmen o sleep diso de s and imp o ed PSQI sco es Kelly e al (2017)50 Heal hy pa icipan s aged 20-33 yea s (n=29) Lac obacillus hamnosus (JB-1) 1x109 CFU Capsule 8 Psychobiological esponseiii o an acu e s esso Cogni i e pe o mance Sleep quali y CANTAB SECPT BDI-2 BAI PSS STAI PSQI P obio ic ea men did no signi ican ly a ec sleep quali y ela i e o placebo ea men Takada e al (2017)26 Heal hy s uden s (n=124) Lac obacillus casei s ain Shi o a YIT 9029. 1.0x109 CFU/ml Milk. 11 Anxie y le els Sleep quali y Sleep e iciency Heal hy habi s Psychological well-being STAI PSQI GHQ OSA HPI Posi i e e ec on sleep du a ion and la ency Culpeppe e al (2016)51 Unde g adua e s uden s (n=581) Lac obacillus hel e icus R0052 (LH), Bi idobac e ium bi idum R0071 (BB) and B. longum spp. in an is R0033 (BI). 3×109 CFU. Capsule 6 S ess le el Sleeping hou s Sel - epo ed s ess sco es Sel - epo ed s ess and le els o sleep Nega i e co ela ion be ween hou s o sleep and sel - epo ed s ess alues Wong e al (2014)52 IBS pa ien s (n=42) Bi idobac e ium longum, B. in an is and B. b e e, Lac obacillus acidophilus, L. casei, L. delb ueckii ssp. bulga icus and L. plan a um and S ep ococcus sali a ius ssp. he mophilus (VSL#3) 112.5 billion iable lyophilized bac e ia Capsule 6 Sleep quali y Day ime sleepiness HADS-A, HADS-D PSQI ESS No signi ican di e ences we e ound be ween he p obio ic g oup and placebo Diop e al (2008)28 Volun ee s wi h s ess symp oms aged 18-60 (n=75) Lac obacillus acidophilus Rosell- 52 and Bi idobac e ium longum Rosell- 175. (3 × 109 CFU) Sache s ick 3 Sleep diso de s Sel - epo ed le els o sleep P obio ic in e en ion did no change s ess- induced sleep p oblems PREBIOTIC Saleh-Ghadimi e al (2022)53 Female obese ype 2 diabe ic melli us pa ien s aged 30–65 (n=63) Nu iose®06 ( esis an dex in) 8 Sleep quali y PSQI P ebio ic in e en ion esul ed in signi ican imp o emen s in sleep quali y when 40 compa ed o he placebo g oup Schaa sma e al (2021)54 Adul s wi h sleep dis u bances aged 30-50 (n=70) P oduc con aining p o ein, GOS, i amins and mine als Sache 3 Sleep quali y PSQI T ea men did no imp o e sleep quali y Buigues e al (2016)29 Ins i u ionalised olde popula ion wi hou demen ia (n=50) Da moca e P e® (Inulin 3375mg and uc o- oligosaccha ides 3488mg (FOS)) Powde 13 E ec o he p ebio ic on he ail y synd ome MMSE AIS No signi ican changes in sleep quali y we e obse ed SYNBIOTIC Valle e al (2021)55 Mili a y unde going ield aining (n=65) Lac obacillus acidophilus LA-5 (2·1 × 108 CFU/g) Bi idobac e ium animalis BB-12 (2·7 × 109 CFU/g) and inulin (2- 3g/60g) Ice c eam 4 Sleep quali y Sleepiness WAM PSQI Sleep quali y did no imp o e signi ican ly in he expe imen al g oup Sleepiness dec eased in he synbio ic- ea ed g oup Que o e al (2021)56 P o essional socce playe s and seden a y s uden s (n=27) Gas eel Plus® (Bi idobac e ium lac is CBP- 001010, Lac obacillus hamnosus CNCM I-4036, Bi idobac e ium longum ES1 (≥1×109 CFU) and FOS (200 mg)) S ick 4 Sleep quali y Anxie y S ess Dep ession Fa igue HLPCQ. STAI PSS BDI BFI The in e en ion only imp o ed he sleep quali y o he a hle es CFU: Colony-Fo ming Uni s; AIS: A hens Insomnia Scale; BDI-2: Beck Dep ession 750 In en o y; CANTAB: The Camb idge Neu opsychological Tes Au oma ed Ba e y; 751 GHQ: Gene al Heal h Ques ionnai e; GHQ-28: The 28-i em Gene al Heal h 752 Ques ionnai e; WAM: Well-being, Ac i i y, Mood ques ionnai e; BAI: The Beck Anxie y 753 In en o y; SRI: S ess Response In en o y; HADS-A, HADS-D: The Hospi al Anxie y 754 and Disease Scale; LEIDS-R: Leiden Index o Dep ession Sensi i i y-Re ised es ; ISI: 755 Insomnia Se e i y Index; MMSE: Mini-Men al S a e Examina ion; NRS: Nume ic Ra ing 756 Scale; OSA: The Ogu i-Shi akawa-Azumi sleep in en o y; POMS: P o ile o Mood S a e; 757 PSQI: Pi sbu gh Sleep Quali y Index; PSS: The Pe cei ed S ess Scale; SECPT: The 758 Socially E alua ed Cold P esso Tes ; STAI: The S a e T ai Anxie y In en o y; Zung-759 SDS: The Zung Sel -Ra ing Dep ession Scale; HPI: Heal h P ac ice Index; ESS: Epwo h 760 Sleepiness Scale; BFI: The B ie Fa igue In en o y; HLPCQ; The Sleep Quali y in 761 Heal hy Li es yle and Pe sonal Con ol Ques ionnai e; DASS-21: Dep ession, Anxie y, 762 and S ess Scale-21 i ems; IBS: i i able bowel synd ome; AFU: Ac i e Fluo escen Uni s; 763 KSD: Ka olinska Sleep Dia y. GOS: galac o-oligosaccha ides; FCC: ib ocy ic change. 764 MADRS: Mon gome y-Åsbe g Dep ession Ra ing Scale; QIDS-SR16: Quick In en o y o 765 Dep essi e Symp oma ology; GAD-7: Gene alized Anxie y Diso de 7-i em scale; MDD: 766 Majo Dep essi e Diso de . 767 41 i This o mula includes Lac obacillus acidophilus (CUL 21+CUL 60) 20 illion CFU, L. hamnosus (CUL 63) 15.55 illion CFU, L. casei (CUL 06) 9.45 illion CFU, L. plan a um (CUL 66) 3.15 illion CFU, L. e men um (CUL 67) 1.35 illion CFU, Bi idobac e ium animalis ssp. lac is (CUL 34) 6.55 illion CFU, B. b e e (CUL 74) 1.35 illion CFU, B. bi idum (CUL 20) 345 million CFU, S ep ococcus he mophilus (CUL 68) 2.25 illion CFU. ii This o mula consis s o Saccha omyces ce e isiae (boula dii) 5 illion CFU. iii This o mula consis s o 112.5 billion iable lyophilized bac e ia: Bi idobac e ium longum, B. in an is and B. b e e, Lac obacillus acidophilus, L. casei, L. delb ueckii ssp. bulga icus and L. plan a um and S ep ococcus sali a ius ssp. he mophilus.