Effect of inulin on the human gut microbiota: stimulation of Bifidobacterium adolescentis and Faecalibacterium prausnitzii

Prebiotics are food ingredients that improve health by modulating the colonic microbiota. The bifidogenic effect of the prebiotic inulin is well established; however, it remains unclear which species of Bifidobacterium are stimulated in vivo and whether bacterial groups other than lactic acid bacteria are affected by inulin consumption. Changes in the faecal microbiota composition were examined by real-time PCR in twelve human volunteers after ingestion of inulin (10 g/d) for a 16-d period in comparison with a control period without any supplement intake. The prevalence of most bacterial groups examined did not change after inulin intake, although the low G+C % Gram-positive species Faecalibacterium prausnitzii exhibited a significant increase (10.3% for control period v. 14.5% during inulin intake, P=0.019). The composition of the genus Bifidobacterium was studied in four of the volunteers by clone library analysis. Between three and five Bifidobacterium spp. were found in each volunteer. Bifidobacterium adolescentis and Bifidobacterium longum were present in all volunteers, and Bifidobacterium pseudocatenulatum, Bifidobacterium animalis, Bifidobacterium bifidum and Bifidobacterium dentium were also detected. Real-time PCR was employed to quantify the four most prevalent Bifidobacterium spp., B. adolescentis, B. longum, B. pseudocatenulatum and B. bifidum, in ten volunteers carrying detectable levels of bifidobacteria. B. adolescentis showed the strongest response to inulin consumption, increasing from 0.89 to 3.9% of the total microbiota (P=0.001). B. bifidum was increased from 0.22 to 0.63% (P<0.001) for the five volunteers for whom this species was present.     

Course of normal and abnormal fatigue in patients with chronic obstructive pulmonary disease, and its relationship with domains of health status

Objective

To examine the difference between patients with normal and patients with abnormal fatigue on aspects of health status, and investigate the natural course of fatigue in patients with Chronic Obstructive Pulmonary Disease (COPD).

Methods

Fatigue, physiological functioning, functional impairment, symptoms, and Quality of Life (QoL) were measured in 168 patients with COPD, and longitudinal data on fatigue of 77 patients were collected.

Results

Fifty percent of patients had abnormal fatigue. Patients with abnormal fatigue reported significantly more problems on the sub-domains of functional impairment (except actual physical activity), symptoms, and QoL as compared to patients with normal fatigue. With respect to physiological functioning patients with normal fatigue scores had better exercise capacity. Four years later the percentage of patients with abnormal fatigue was increased to 64%. In 1/3 of the patients an increase of more than the minimal clinically important difference was found.

Conclusion

Many COPD patients suffer from abnormal fatigue. Patients with abnormal fatigue have more limitations on many aspects of health status, especially on symptoms, functional impairment, and QoL.

Practice implications

Fatigue should be evaluated in usual care with a questionnaire that corrects for normal fatigue in order to tailor treatment to patients’ need.