Bifidogenic effect of whole-grain wheat during a 12-week energy-restricted dietary intervention in postmenopausal women

• Published in: European journal of clinical nutrition Vol. 67; no. 12; pp. 1316 - 1321
• Main Authors: Christensen, E G, Licht, T R, Kristensen, M, Bahl, M I
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-12-2013; Nature Publishing Group
• Subjects: 692/698/2741/2135; 692/700/2814; Abundance; Animal models; Bacteria; Bifidobacterium; Bifidobacterium - genetics; Bifidobacterium - growth & development; Biological and medical sciences; Caco-2 Cells; Caloric Restriction; Clinical Nutrition; Composition; Consumption; Diet; Dietary restrictions; Digestive system; DNA, Bacterial - analysis; Electric Impedance; Epidemiology; Epithelium - physiology; Feces - microbiology; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Gastrointestinal tract; Grain; Health aspects; Humans; Integrity; Internal Medicine; Intervention; Intestinal microflora; Intestine; Intestines - microbiology; Medical sciences; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolites; Microbiota; original-article; Physiological aspects; Post-menopause; Postmenopausal women; Postmenopause; Prebiotics; Public Health; Relative abundance; Salmonella; Seeds; Triticum; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Wheat; Wheat products; Denmark; whole grain; gut microbiota; intestinal integrity; Bifidobacteria; Human; Bifidobacteria; Digestive system; Gut; Metabolic diseases; gut microbiota; Feeding; intestinal integrity; Energy; Diet; Whole grain; Postmenopause; Cereal; Female; Woman; Wheat
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/ejcn.2013.207

Background/Objectives:
Consumption of whole-grain products is known to have beneficial effects on human health. The effects of whole-grain products on the intestinal microbiota and intestinal integrity have, however, only been studied limitedly. We investigate changes of the human gut microbiota composition after consumption of whole-grain (WW) or refined wheat (RW) and further study effects on gut wall integrity.
Subjects/Methods:
Quantitative PCR was used to determine changes in the gut bacterial composition in postmenopausal women following a 12-week energy-restricted dietary intervention with WW (
N
=38) or RW (
N
=34). Intestinal integrity was determined by measuring trans-epithelial resistance (TER) across a Caco-2 cell monolayer, following exposure to faecal water.
Results:
No significant differences in microbiota composition were observed between the two dietary groups; however, the whole-grain intervention increased the relative abundance of
Bifidobacterium
compared to baseline, supporting a prebiotic effect of whole-grain wheat. Faecal water increased TER independent of dietary intervention, indicating that commensal bacteria produce metabolites that generally provide a positive effect on intestinal integrity. Combining microbiota composition data from the run-in period with its effect on TER revealed a tendency for a negative correlation between the relative abundance of
Bifidobacterium
and TER (
P
=0.09). This contradicts previous findings but supports observations of increased
Salmonella
infection in animal models following treatment with bifidogenic prebiotics.
Conclusions:
The present study shows that whole-grain wheat consumption increases the abundance of bifidobacteria compared to baseline and may have indirect effects on the integrity of the intestinal wall.