Dietary modulation of the gut microbiota – a randomised controlled trial in obese postmenopausal women

Abstract

The gut microbiota has been implicated in obesity and its progression towards metabolic disease. Dietary interventions that target the gut microbiota have been suggested to improve metabolic health. The aim of the present study was to investigate the effect of interventions with Lactobacillus paracasei F19 or flaxseed mucilage on the gut microbiota and metabolic risk markers in obesity. A total of fifty-eight obese postmenopausal women were randomised to a single-blinded, parallel-group intervention of 6-week duration, with a daily intake of either L. paracasei F19 (9·4 × 1010 colony-forming units), flaxseed mucilage (10 g) or placebo. Quantitative metagenomic analysis of faecal DNA was performed to identify the changes in the gut microbiota. Diet-induced changes in metabolic markers were explored using adjusted linear regression models. The intake of flaxseed mucilage over 6 weeks led to a reduction in serum C-peptide and insulin release during an oral glucose tolerance test (P< 0·05) and improved insulin sensitivity measured by Matsuda index (P< 0·05). Comparison of gut microbiota composition at baseline and after 6 weeks of intervention with flaxseed mucilage showed alterations in abundance of thirty-three metagenomic species (P< 0·01), including decreased relative abundance of eight Faecalibacterium species. These changes in the microbiota could not explain the effect of flaxseed mucilage on insulin sensitivity. The intake of L. paracasei F19 did not modulate metabolic markers compared with placebo. In conclusion, flaxseed mucilage improves insulin sensitivity and alters the gut microbiota; however, the improvement in insulin sensitivity was not mediated by the observed changes in relative abundance of bacterial species.

Probiotic Foods and Supplements Interventions for Metabolic Syndromes: A Systematic Review and Meta-Analysis of Recent Clinical Trials

“…Since all reviewed studies have similarities in allocation (randomized), endpoint classification (surrogate), and primary purpose (treatment), the authors in this study did not list this information in the study design section in Table 1. As it was shown in Table 1, only the study by Brahe et al [38] used single-blinding methods; all other studies used double-blinding in their research (n = 17). Ten studies used a 2-treatment-arm design, 5 studies used a 3-treatment-arm design, 2 studies used a 4-treatment-arm design, and one study used a 5-treatment-arm design.…”

“…As mentioned above, only one study [38] used a singleblind method, and all the others used double-blind methods. Also, all reviewed RCTs had small intervals.…”

“…The reasons for the removal include lack of original data [47], data without specific SD of fasting glucose [48], and outcome indicator being serum glucose, not fasting glucose [42]. Among the remaining 7 studies, 5 of them found no significant differences in fasting glucose or blood glucose in between-group comparisons [38,43,50,55,57]. In the 2014 4-arm study by Ivey et al [66], the researchers used a 4-arm approach: (A) probiotic yogurt plus probiotic capsules, (B) probiotic yogurt plus placebo capsules, (C) control milk plus probiotic capsules, and (D) control milk plus placebo capsules.…”

Do You Really Want a Hunter-gatherer Microbiota? Perils and Pitfalls for Your Gut

“…They also tracked microbiota. However, the blood sugar improvements did not correlate with changes in the microbiota [33]. This study infers that microbiota tests are important, and clinician's participation in gathering data is needed but clinical utility is still in future.…”

Historical perspective: gut dysbiosis and hypertension

“…Further experiments demonstrating effects of gut dysbiosis on hypertension are clearly necessary. The older and new data in rats and humans provide a rationale for further investigations since this concept may offer a new mechanism for treating hypertension with diet, probiotics, antibiotics, or fecal transplants as seen with other pathologies (5,25,32,37).…”