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Daily intake of wheat germ-enriched bread may promote a healthy gut bacterial microbiota: a randomised controlled trial



Wheat bran fibre has a beneficial effect on gastrointestinal function, but evidence for wheat germ is scarce. Accordingly, we evaluated the effects of daily intake of wheat germ on gastrointestinal discomfort and gut microbiota by adding wheat germ to refined (white) wheat bread, the most consumed bread type. We hypothesised that an improvement in the composition of refined bread could beneficially affect intestinal health without compromising consumers’ acceptance.


Fifty-five healthy adults were recruited for a randomised, double-blind, crossover, controlled trial comprising two 4-week intervention periods separated by a 5-week washout stage. During the first 4-week period, one group consumed wheat bread enriched with 6 g of wheat germ and the control group consumed non-enriched wheat bread.


Wheat germ-enriched bread was well-appreciated and the number of participants that demonstrated minimal gastrointestinal improvements after wheat-germ intake was higher than in the control arm. Importantly, intake of wheat germ-enriched bread decreased the perceived gastrointestinal discomfort-related quality of life (subscale worries and concerns) over refined white bread. The improvements in the gastrointestinal function were accompanied by favourable changes in gut microbiota, increasing the number of Bacteroides spp. and Bifidobacterium spp.


Adding wheat germ to industrially made white bread without altering sensory properties may promote a healthy gut bacterial microbiota and the gastrointestinal health.

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(adapted from Moreira-Rosário et al. [30])

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AM-R, CC, and LFA were responsible for the study design, carrying out the trial, data analysis, manuscript writing, and final revision. CM, HP, SN and DS were partially responsible for the data collection and analysis. JAT collaborated in the study design and final revision of the manuscript. AM-R and LFA were responsible for the statistical analysis. CC and LFA were coordinators of the project, with an equal contribution. This work is part of the VALORINTEGRADOR project, and was supported by the Programa Operacional Competitividade e Internacionalização and by National Funds through the Fundação para a Ciência e a Tecnologia (through the operations FCOMP-01-0202-FEDER-038861 and POCI-01-0145-FEDER-007746). Our thanks to Germen and Padaria Ribeiro for the production of the bread used in this trial. We would like to thank Francisca Mendes for her assistance in laboratory work. We are also especially grateful to all participants for their enthusiastic collaboration in this study. We extend our thanks to Milaydis Sosa-Napolskij for proof reading this manuscript.

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Correspondence to André Moreira-Rosário.

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Moreira-Rosário, A., Marques, C., Pinheiro, H. et al. Daily intake of wheat germ-enriched bread may promote a healthy gut bacterial microbiota: a randomised controlled trial. Eur J Nutr 59, 1951–1961 (2020).

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  • Gastrointestinal discomfort
  • Gut microbiota
  • Bread
  • Wheat germ
  • Randomised controlled trial