Impact of partially hydrolyzed guar gum (PHGG) on constipation prevention: A systematic review and meta-analysis

Dietary fiber is part of the diet of many people worldwide and is commonly recognized as a health food. The aim of this study was to quantitatively evaluate the impact of partially hydrolyzed guar gum (PHGG) supplementation on constipation prevention related outcomes in apparently healthy individuals. An extensive electronic and manual bibliographic search of controlled trials was undertaken in PubMed, Embase, the Cochrane Library, and JST database as part of a wider scoping review from inception to September 2016, and a systematic review and meta-analysis was performed. The pooled effect of PHGG supplementation on constipation was assessed using fixed-effects or random-effects model. The outcomes of interest were fecal defecation frequency (FDF), fecal weight (FW), fecal moisture (FM), fecal volume (FV) and fecal excretory feeling (FEF). Fifteen trials of seven enrolled studies (4 RCTs & 3 non-RCTs) administrated PHGG involving only healthy volunteers comprising a total of 325 participants, indicated that PHGG has a favorable efficacy success rate of constipation reduction, while no adverse events were observed in context of the studies included. Trials revealed a highly significant statistically pooling difference (P<0.00001) in pre- and post-intervention changes in FDF (SMD: 0.58times/day; 95%CI, 0.43–0.74; I2=0, p=0.54) in the fixed-effects model. A dose-response curve revealed a tendency toward a significant relationship (p=0.011) between FDF and dosage of PHGG, wherein the coefficient of relation (r) was 0.31. The finding revealed that daily dosage of 5–7g PHGG is sufficient to ameliorate the FDF among the healthy participants with constipation conditions. Five studies involved in elderly and children were also evaluated separately for the reference. Results suggested that PHGG consumption led to a favorable impact on constipation prevention of the similar magnitude that was achieved with laxatives.