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. 2025 Jul 2;13(7):1561.
doi: 10.3390/microorganisms13071561.

Effects of Blackcurrant Extract and Partially Hydrolyzed Guar Gum Intake on Gut Dysbiosis in Male University Rugby Players

Hiroto Miura  1 , Machi Oda  1 , Kanako Abe  1 , Hiromi Ikeda  1 , Mami Fujibayashi  2 , Naoko Oda  2 , Tomohiro Segawa  3 , Aya Abe  4 , Natsumi Ueta  5 , Takamitsu Tsukahara  6 , Tomohisa Takagi  7 , Yuji Naito  8 , Ryo Inoue  1
Affiliations

Effects of Blackcurrant Extract and Partially Hydrolyzed Guar Gum Intake on Gut Dysbiosis in Male University Rugby Players

Hiroto Miura et al. Microorganisms. .

Abstract

Our previous study reported that male university rugby players tended to have a gut with a dysbiotic environment, characterized by abundant pathobiont bacteria and an accumulation of succinate, when compared with age-matched, non-rugby playing healthy males. In the present study, we conducted a randomized, double-blinded, placebo-controlled experiment to evaluate the potential of blackcurrant extract and/or partially hydrolyzed guar gum (PHGG) to improve the gut environment of university rugby players. Participants were supplemented with blackcurrant extract and/or PHGG or a placebo for 4 weeks. Beneficial gut bacteria such as Megasphaera spp. tended to increase (p < 0.10) and Bifidobacterium spp. increased (p < 0.05) with the intake of blackcurrant extract and/or PHGG. A subgroup analysis further indicated that, unlike in those with a eubiotic gut environment, the dietary supplements also increased the number of beneficial gut bacteria such as Phascolarctobacterium spp. (p < 0.10) and Faecalibacterium spp. (p < 0.10) and fecal SCFA concentrations (p < 0.05) in participants with a possible dysbiotic gut environment. However, a synergistic effect between blackcurrant extract and PHGG was not clearly observed. Although further investigation is recommended, it was concluded that blackcurrant extract and PHGG can at least be used as functional materials to improve gut dysbiosis in university rugby players.

Keywords: blackcurrant; dysbiosis; gut microbiota; partially hydrolyzed guar gum; rugby.

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Conflict of interest statement

N.U. is employed by Morishita Jintan Corporation, which sells blackcurrant extract commercially. A.A. is employed by Taiyo Kagaku Corporation, which sells PHGG commercially. R.I. received collaboration research funds from Morishita Jintan Corporation and Taiyo Kagaku Corporation. YN received scholarship funds from Taiyo Kagaku Co. Ltd., Morishita-Jintan Co. Ltd., and a collaboration research fund from Taiyo Kagaku Co. Ltd. The present research was partly supported by these funds. Neither the funding agency nor any outside organization has participated in the study design or have any competing interests. These companies have approved the final version of the manuscript. Other authors have no conflicts of interest.

Figures

Figure 1
Figure 1
Flow chart of study participants. PC, placebo group; BC, blackcurrant group; GG, guar gum group; CO, combination of blackcurrant and guar gum group; BDHQ, brief dietary history questionnaire; SCFA, short-chain fatty acid. * Participants who did not provide samples or questionnaires due to personal reasons were excluded from downstream analyses.
See this image and copyright information in PMC

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