Human study shows flaxseed fibres modulate gut microbiota and improve insulin sensitivity

Prebiotics and probiotics are food components that directly target the gut microbiota. This recent human study investigated their effects on gut microbiota and metabolic risk markers in obesity.

In this trial, researchers tested the probiotic Lactobacillus paracasei, which has been associated with a healthy metabolic profile in previous research. They also tested flaxseed — composed of 30% dietary fibres, including soluble viscous fibres (mucilage) — as a possible prebiotic.

In this randomised trial, obese postmenopausal women (n=58) consumed Lactobacillus paracasei F19, flaxseed mucilage, or a placebo daily for six weeks.

The group of women consuming L. paracasei F19 showed no differences in metabolic profile compared to those in the placebo group. Those consuming flaxseed mucilage showed improved insulin sensitivity as well as lower serum C-peptide and insulin release in a glucose tolerance test. Fecal samples identified changes in gut microbiota in the flaxseed-consuming group: the relative abundance of 33 species was altered, yet these changes could not explain how flaxseed mucilage affected insulin sensitivity.


Brahe LK, et al. (2015) Dietary modulation of the gut microbiota – a randomised controlled trial in obese postmenopausal women. British Journal of Nutrition. doi:10.1017/S0007114515001786

Paul Enck
Paul Enck
Prof. Dr. Paul Enck, Director of Research, Dept. of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Germany. His main interests are gut functions in health and disease, including functional and inflammatory bowel disorders, the role of the gut microbiota, regulation of eating and food intake and its disorders, of nausea, vomiting and motion sickness, and the psychophysiology and neurobiology of the placebo response, with specific emphasis on age and gender contributions. He has published more than 170 original data paper in scientific, peer-reviewed journals, and more than 250 book chapters and review articles. He is board member/treasurer of the European Society of Neurogastroenterology and Motility and of the German Society of Neurogastroenterology and Motility, and has served as reviewer for many international journals and grant agencies.