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Am. J. Clin. Nutr..2020 06;111(6):1286-1296. 5823789. doi: 10.1093/ajcn/nqaa074.


Effect of chicory inulin-type fructan-containing snack bars on the human gut microbiota in low dietary fiber consumers in a randomized crossover trial.

  • Raylene A Reimer
  • Adriana Soto-Vaca
  • Alissa C Nicolucci
  • Shyamchand Mayengbam
  • Heekuk Park
  • Karen L Madsen
  • Ravi Menon
  • Elaine E Vaughan
PMID: 32320024 DOI: 10.1093/ajcn/nqaa074.




BACKGROUND: The low intake of dietary fiber compared to recommended amounts has been referred to as the dietary fiber gap. The addition of fiber to snack foods could favorably alter gut microbiota and help individuals meet intake recommendations.



OBJECTIVES: Our objective was to examine the effect of low- and moderate-dose fiber-containing snack bars, comprising mainly chicory root inulin-type fructans (ITF), on gut microbiota in healthy adults with habitual low dietary fiber intake using 16S ribosomal RNA-based approaches.


2つの別々の4週間プラセボ対照二重盲検クロスオーバー試験において、食物繊維摂取量の少ない健康な成人50人を、試験1では中用量食物繊維(7 g/d)または対照(n=25)、試験2では低用量食物繊維(3 g/d)または対照(n=25)のいずれかのイソカロリックスナックバーを受けるように無作為に割り付け、4週間のウォッシュアウト期間を設けた。糞便微生物組成と推察機能、糞便SCFA濃度、胃腸(GI)症状、食事摂取量、生活の質を測定した。

METHODS: In 2 separate 4-wk, placebo-controlled, double-blind, crossover trials, 50 healthy adults with low dietary fiber intake were randomly assigned to receive isocaloric snack bars of either moderate-dose fiber (7 g/d) or control in Trial 1 (n = 25) or low-dose fiber (3 g/d) or control in Trial 2 (n = 25), with 4-wk washout periods. Fecal microbiota composition and inferred function, fecal SCFA concentration, gastrointestinal (GI) symptoms, dietary intake, and quality of life were measured.


中等量投与群では、対照群と比較して、複数の微生物分類群で有意な差が認められ、特にビフィドバクテリウム属の相対的な存在量が(平均±SEM)5.3%±5.9%から18.7%±15.0%へと増加していた。低用量ITFでは、多重比較補正後はビフィドバクテリウムの有意な増加は認められなくなったが、qPCRによる標的解析ではビフィドバクテリウムの有意な増加が認められた。予測機能プロファイリングでは、中用量のバーを摂取した後の予測機能の変化が確認されたが、低用量のバーを摂取した後の予測機能の変化は確認されなかった。糞便 SCFAs は時間の影響を受けたが、治療法の影響は受けなかった。GI症状のグループ間差は認められなかった。重要なことは、食物繊維の摂取量が中等量および低用量バーで有意に増加したことである。

RESULTS: Compared with the control group, the moderate-dose group showed significant differences across multiple microbial taxa, most notably an increased relative abundance of the Bifidobacterium genus from (mean ± SEM) 5.3% ± 5.9% to 18.7% ± 15.0%. With low-dose ITF, significant increases in Bifidobacterium were no longer present after correction for multiple comparisons but targeted analysis with qPCR showed a significant increase in Bifidobacterium. Predictive functional profiling identified changes in predicted function after intake of the moderate- but not the low-dose bar. Fecal SCFAs were affected by time but not treatment. There were no between-group differences in GI symptoms. Importantly, fiber intake increased significantly with the moderate- and low-dose bars.



CONCLUSIONS: In healthy adults, adding 3 or 7 g ITF to snack bars increased Bifidobacterium, a beneficial member of the gut microbial community. The addition of ITF to food products could help reduce the dietary fiber gap prevalent in modern life.This trial was registered at clinicaltrials.gov as NCT03042494.

Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.