Probiotics, prebiotics and synbiotics use in neonates : a critical appraisal of the evidence and evaluation of its application by the food industry

Mugambi, Mary Letizia Nkatha (2014-04)

Thesis (PhD)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: Background: Synbiotics, probiotics and prebiotics are being added to infant formula. This study was an in-depth evaluation of research on infants fed infant formula containing synbiotics, probiotics or prebiotics and was carried out in two phases. Phase one included two systematic reviews that assessed if synbiotics, probiotics or prebiotics led to improved growth and clinical outcomes in formula fed full term and preterm infants. Phase two included two studies: A systematic review compared the methodological quality and outcomes of industry and non-industry sponsored randomized controlled trials (RCTs) and a descriptive study evaluated how the food industry applies the knowledge and evidence gained from probiotics, prebiotics or synbiotics research in infants. The research questions were: Does the consumption of probiotics, prebiotics or synbiotics supplemented infant formula lead to improved clinical outcomes in infants? Is there an association between source of funding and methodological quality, clinical outcomes and author’s conclusions in trials using probiotics, prebiotics or synbiotics supplemented formula in infants? Does the food industry use the evidence gained through probiotics, prebiotics and synbiotics research trials on infants for the benefit of the general paediatric population? The hypotheses were: Consumption of probiotics, prebiotics or synbiotics by infants leads to improved clinical outcomes; The source of funding in research trials using probiotics, prebiotics or synbiotics supplemented formula in infants is associated with outcomes in favour of the sponsor’s products and authors’ conclusions; Methodological qualities of non-industry sponsored trials are equivalent to industry sponsored trials; Evidence gathered through probiotics, prebiotics and synbiotics research is implemented by the food industry. Methods: Phase one: Both systematic reviews on preterm and full term infants: Cochrane methodology was followed using RCTs which compared preterm or full term formula containing probiotics, prebiotics or synbiotics to conventional infant formula with / without placebo among healthy preterm or full term infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Phase two: In the systematic review, Cochrane methodology was used to assess the risk of bias of included RCTs. Association between source of funding and risk of bias, clinical outcomes and conclusions were assessed. In the descriptive study, all listed companies that manufacture infant food products with added synbiotics, probiotics or prebiotics for infants were identified and invited to participate. A letter of invitation was sent and if they expressed willingness to take part in the study, a questionnaire with a written consent form was sent. Descriptive statistics and associations between categorical variables were to be tested using a Chi-square test. Results: Phase one: Review on preterm infants: 8 studies were included. Probiotics increased stool frequency with no effect on other clinical outcomes. Prebiotics increased stool frequency and bifidobacteria counts only. Review on full term infants: 25 studies were included. Synbiotics improved stool frequency but had no effect on other clinical outcomes. Probiotics did not have an effect on any clinical outcome. Prebiotics increased weight gain and stool frequency with no effect on other outcomes. Phase two: Systematic review: 67 studies were included, majority were funded by food industry. There was no significant association between the source of funding and four domains (sequence generation, allocation concealment, blinding, selective reporting), majority of reported clinical outcomes or authors’ conclusions. Source of funding was significantly associated with two domains (incomplete outcome data, free of other bias), antibiotic use and conclusions on weight gain. Descriptive study: 25 companies were identified and invited to participate. No company agreed to participate in the survey for different reasons. Conclusions Phase one: Review on preterm infants: There is not enough evidence to state that supplementation with probiotics or prebiotics results in improved growth and clinical outcomes in exclusively formula fed preterm infants. Review on full term infants: There is not enough evidence to state that supplementation of term infant formula with synbiotics, probiotics or prebiotics does result in improved growth or clinical outcomes in term infants. There is no data available to establish if synbiotics are superior to probiotics or prebiotics. Phase two: Systematic review: In RCTs on infants fed infant formula containing probiotics, prebiotics or synbiotics, the source of funding does not influence majority of outcomes in favour of the sponsors’ products. More non-industry funded research is needed to further assess the impact of funding on reported clinical outcomes and authors’ conclusions. Descriptive study: Due to companies refusing to participate in this study, no conclusion could be drawn on how the food industry applies evidence gained through probiotics, prebiotics or synbiotics research on infants. More transparency is needed from the infant formula manufactures on how they apply the evidence gained from probiotic, prebiotic or synbiotic research on infants.

AFRIKAANSE OPSOMMING: Agtergrond Synbiotika, probiotika en prebiotika word gereeld by baba formule gevoeg. Hierdie studie was 'n in-diepte evaluering van navorsing oor babas gevoed met formule melk wat synbiotika, probiotika of prebiotika bevat en is uitgevoer in twee fases. Fase een het twee sistematiese oorsigte ingesluit wat die rol van synbiotika, probiotika en prebiotika op verbeterde groei en kliniese uitkomste van formule gevoede volterm babas en vroeg gebore babas evalueer het. Fase twee het bestaan uit twee studies: 'n sistematiese oorsig wat die metodologiese kwaliteit en uitkomste van die bedryf en nie-bedryf geborgde ewekansige gekontroleerde proewe (RCTs) evalueer het, asook 'n beskrywende studie wat die kennis en toepassing van bewyse oor die effektiewiteit van probiotika, prebiotika of synbiotika in die voedsel industrie bestudeer het. Die hipotese stellings was: verbruik van probiotika, prebiotika of synbiotika by babas lei tot verbeterde kliniese uitkomste; die bron van befondsing vir synbiotics, probiotika of prebiotika navorsing beïnvloed uitkomste ten gunste van die borg se produkte; bewyse ingesamel deur middel van probiotika, prebiotika en synbiotika navorsing word geïmplementeer deur die voedselindustrie. Metodes Fase een: Beide sistematiese oorsigte op volterm en premature babas: Cochrane metodes is gevolg deur ewekansige, gekontroleerde studies wat vol termyn of premature formule met probiotika, prebiotika of synbiotika met konvensionele baba formule met / sonder plasebo onder gesonde volterm of premature babas bestudeer. Die gemiddelde verskil (MD) en die ooreenstemmende 95% vertrouensintervalle is gebruik vir deurlopende uitkomste, risiko verhouding (RR) en die ooreenstemmende 95% CI vir tweeledige uitkomste. Fase twee: In die sistematiese oorsig is Cochrane metodiek gebruik om die risiko van vooroordeel van ingesluite ewekansige, gekontroleerde studies te evalueer. Assosiasie tussen bron van befondsing en die risiko van vooroordeel, asook kliniese uitkomste en gevolgtrekkings was beoordeel. In die beskrywende studie, is alle genoteerde maatskappye wat babavoeding produkte vervaardig met bygevoegde synbiotika, probiotika of prebiotika vir babas geïdentifiseer en uitgenooi om deel te neem. 'n Uitnodigingsbrief is vir die relevante maatskappye gestuur om hul bereidwilligheid om deel te neem te bevestig. Indien hulle wel bereid was om deel te neem was 'n vraelys met 'n skriftelike toestemming vorm gestuur. Beskrywende statistiek en assosiasies tussen kategoriese veranderlikes was getoets met behulp van 'n Chi-kwadraat toets. Resultate Fase een: Oorsig oor premature babas: 8 studies was ingesluit. Probiotika verhoog stoelgang frekwensie met geen effek op ander kliniese uitkomste. Prebiotika verhoog ook stoelgang frekwensie en slegs bifidobakteriële tellings. Oorsig oor die vol termyn babas: 25 studies was ingesluit. Synbiotika verbeter stoelgang frekwensie, maar het geen effek op ander kliniese uitkomste gehad nie. Probiotika het nie 'n effek op enige kliniese uitkoms gehad nie. Prebiotika verhoog gewigstoename en stoelgang frekwensie met geen effek op ander uitkomste. Fase twee: Sistematiese oorsig: 67 studies was ingesluit, en die meerderheid was befonds deur die voedsel bedryf. Daar was geen beduidende assosiasie tussen die bron van befondsing en vier gebiede (toekenningsvolgorde, toekenningsverberging, studie verblinding, selektiewe verslaggewing), en die meerderheid van gerapporteerde kliniese uitkomste of skrywers se gevolgtrekkings. Die bron van befondsing was beduidend verbind met twee gebiede (onvolledige uitslag data, vry van ander vooroordeel), antibiotika gebruik en gevolgtrekkings op gewigstoename. Beskrywende studie: 25 maatskappye is geïdentifiseer en genooi om deel te neem. Geen maatskappy het ingestem om deel te neem aan die studie om verskillende redes. Gevolgtrekkings Fase een: Oorsig oor premature babas: Daar is nie genoeg bewyse dat die aanvulling met probiotika of prebiotika resultate in verbeterde groei en kliniese uitkomste in uitsluitlik formule gevoede premature babas tot gevolg het nie. Oorsig oor die volle termyn babas: Daar is nie genoeg bewyse om te sê dat die aanvulling van term baba formule met synbiotika, probiotika of prebiotika lei tot verbeterde groei of kliniese uitkomste in termyn babas. Daar is geen inligting beskikbaar om te stel of synbiotika beter is as probiotika of prebiotika nie. Fase twee: Sistematiese oorsig: In studies op babas gevoed met formule melk wat probiotika, prebiotika of synbiotika bevat het, het die bron van befondsing nie meerderheid van die uitkomste in die guns van die borge se produkte beïnvloed nie. Meer nie-industrie befondsde navorsing is nodig om verder die impak van befondsing op kliniese uitkomste en skrywers se gevolgtrekkings te evalueer. Beskrywende studie: Aangesien al die maatskappy deelname geweier het, kon geen gevolgtrekking gemaak word of die voedsel bedryf bewyse oor die gebruik van probiotika, prebiotika of synbiotika toepas nie. Meer deursigtigheid is nodig van die formule vervaardigers oor hoe hulle die bewyse oor die gebruik van probiotika, prebiotika of synbiotika toepas.

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