TY - JOUR

T1 - Whole-grain rye and wheat affect some markers of gut health without altering the fecal microbiota in healthy overweight adults

T2 - A 6-week randomized trial

AU - Vuholm, Stine

AU - Nielsen, Dennis Sandris

AU - Iversen, Kia Nøhr

AU - Suhr, Julie

AU - Westermann, Peter

AU - Krych, Lukasz

AU - Andersen, Jens Rikardt

AU - Kristensen, Mette

N1 - CURIS 2017 NEXS 260

PY - 2017

Y1 - 2017

N2 - Background: 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/m(2))] 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 (-38%) group compared to the WGW (25%, P = 0.014) and WGR groups (-1%, 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 of WGR and WGW affected fecal butyrate concentration and gastrointestinal symptoms in healthy overweight adults, supporting the hypothesis that WGR and WGW can be included in the diet equally to maintain gut health. This trial was registered at clinicaltrials.gov as NCT02358122.

AB - Background: 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/m(2))] 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 (-38%) group compared to the WGW (25%, P = 0.014) and WGR groups (-1%, 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 of WGR and WGW affected fecal butyrate concentration and gastrointestinal symptoms in healthy overweight adults, supporting the hypothesis that WGR and WGW can be included in the diet equally to maintain gut health. This trial was registered at clinicaltrials.gov as NCT02358122.

KW - Whole grain

KW - Rye

KW - Wheat

KW - Microbiota

KW - Gut health

U2 - 10.3945/jn.117.250647

DO - 10.3945/jn.117.250647

M3 - Journal article

C2 - 28954842

VL - 147

SP - 2067

EP - 2075

JO - Journal of Nutrition

JF - Journal of Nutrition

SN - 0022-3166

IS - 11

ER -