Whole-grain rye and wheat affect some markers of gut health without altering the fecal microbiota in healthy overweight adults: A 6-week randomized trial
Journal article, 2017

Whole grains have shown potential for improving gut health, but evidence comparing different whole-grain types is lacking. Objective:We investigated whether whole-grain wheat (WGW) and whole-grain rye (WGR) improve gut health in different ways compared to refined wheat (RW), with the primary outcomes of microbiota composition and gastrointestinal (GI) symptoms. Methods: In a randomized parallel trial, 70 healthy adults (in means ± SDs; aged 51.0 ± 9.4 y, body mass index [BMI (in kg/m2)] 27.8 ± 1.9, 32:38 men:women) replaced cereal foods from their habitual diet with WGR, WGW, or RW (control). Before and after a 6-wk intervention, a spot stool sample was collected and analyzed for short-chain fatty acids and microbiota composition through the use of 16S ribosomal RNA gene-targeted high-throughput amplicon sequencing. GI symptoms and stool regularity were evaluated by questionnaires at baseline and after weeks 2, 4, and 6. Results: Intakes of whole grains were 145.2 ± 75.9, 124.2 ± 57.3, and 5.4 ± 3.2 g/d in the WGW, WGR, and RW groups, respectively. Gut microbiota composition was not affected by diet. The relative change in fecal butyrate decreased in the RW (238%) group compared to the WGW (25%, P = 0.014) and WGR groups (21%, P = 0.037). Other short-chain fatty acids were unaffected. Flatulence was more frequent following intake of WGW (OR: 2.06, 95% CI: 1.03, 4.17) and WGR (OR: 2.62, 95% CI: 1.35, 5.22) compared to RW, whereas bloating was less frequent following WGW (OR: 0.38, 95% CI: 0.18, 0.80) and WGR (OR: 0.34, 95% CI: 0.16, 0.72). Stool frequency increased following WGR but not WGW, compared to RW in weeks 2 (0.4 defecations/d, P = 0.049) and 4 (0.5 defecations/d, P = 0.043), but not in week 6. The WGW and WGR groups did not differ from each other in any of the variables tested. Conclusion: Regular consumption ofWGR andWGWaffected fecal butyrate concentration and gastrointestinal symptoms in healthy overweight adults, supporting the hypothesis thatWGR andWGWcan be included in the diet equally tomaintain gut health.

Gut health

Whole grain

Rye

Microbiota

Wheat

Author

S. Vuholm

University of Copenhagen

D.S. Nielsen

University of Copenhagen

Kia Noehr Iversen

University of Copenhagen

J. Suhr

University of Copenhagen

P. Westermann

Aalborg University

L. Krych

University of Copenhagen

J.R. Andersen

University of Copenhagen

M. Kristensen

University of Copenhagen

Journal of Nutrition

0022-3166 (ISSN) 1541-6100 (eISSN)

Vol. 147 11 2067-2075

Subject Categories

Nutrition and Dietetics

DOI

10.3945/jn.117.250647

More information

Latest update

6/3/2019 1