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Systematic review assessing the effectiveness of dietary intervention on gut microbiota in adults with type 2 diabetes

Lookup NU author(s): Dr Dave Houghton, Dr Timothy Hardy, Dr Christopher StewartORCiD, Linda Errington, Professor Chris Day, Professor Mike TrenellORCiD, Dr Leah Avery



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2018 The Author(s) Aims/hypothesis: Despite improved understanding of the pathophysiology of type 2 diabetes mellitus, explanations for individual variability in disease progression and response to treatment are incomplete. The gut microbiota has been linked to the pathophysiology of type 2 diabetes mellitus and may account for this variability. We conducted a systematic review to assess the effectiveness of dietary and physical activity/exercise interventions in modulating the gut microbiota and improving glucose control in adults with type 2 diabetes mellitus. Methods: A systematic search was conducted to identify studies reporting on the effect of dietary and physical activity/exercise interventions on the gut microbiota and glucose control in individuals with a confirmed diagnosis of type 2 diabetes mellitus. Study characteristics, methodological quality and details relating to interventions were captured using a data-extraction form. Meta-analyses were conducted where sufficient data were available, and other results were reported narratively. Results: Eight studies met the eligibility criteria of the systematic review. No studies were found that reported on the effects of physical activity/exercise on the gut microbiota and glucose control. However, studies reporting on dietary interventions showed that such interventions were associated with modifications to the composition and diversity of the gut microbiota. There was a statistically significant improvement in HbA1c (standardised mean difference [SMD] −2.31 mmol/mol [95% CI −2.76, −1.85] [0.21%; 95% CI −0.26, −0.16]; I2 = 0%, p < 0.01), but not in fasting blood glucose (SMD −0.25 mmol/l [95% CI −0.85, 0.35], I2 = 87%, p > 0.05), fasting insulin (SMD −1.82 pmol/l [95% CI −7.23, 3.60], I2 = 54%, p > 0.05) or HOMA-IR (SMD −0.15 [95% CI −0.63, 0.32], I2 = 69%, p > 0.05) when comparing dietary interventions with comparator groups. There were no significant changes in the relative abundance of bacteria in the genera Bifidobacterium (SMD 1.29% [95% CI −4.45, 7.03], I2 = 33%, p > 0.05), Roseburia (SMD −0.85% [95% CI −2.91, 1.21], I2 = 79%, p > 0.05) or Lactobacillus (SMD 0.04% [95% CI −0.01, 0.09], I2 = 0%, p > 0.05) when comparing dietary interventions with comparator groups. There were, however, other significant changes in the gut microbiota, including changes at various taxonomic levels, including phylum, family, genus and species, Firmicutes:Bacteroidetes ratios and changes in diversity matrices (α and β). Dietary intervention had minimal or no effect on inflammation, short-chain fatty acids or anthropometrics. Conclusions/interpretation: Dietary intervention was found to modulate the gut microbiota and improve glucose control in individuals with type 2 diabetes. Although the results of the included studies are encouraging, this review highlights the need for further well-conducted interventional studies to inform the clinical use of dietary interventions targeting the gut microbiota.

Publication metadata

Author(s): Houghton D, Hardy T, Stewart C, Errington L, Day CP, Trenell MI, Avery L

Publication type: Article

Publication status: Published

Journal: Diabetologia

Year: 2018

Volume: 61

Issue: 8

Pages: 1700-1711

Print publication date: 01/08/2018

Online publication date: 12/05/2018

Acceptance date: 05/03/2018

Date deposited: 31/05/2018

ISSN (print): 0012-186X

ISSN (electronic): 1432-0428

Publisher: Springer Verlag


DOI: 10.1007/s00125-018-4632-0


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Funder referenceFunder name
Diabetes UK
Health-F2-2009-241762Commission of the European Communities