Dietary fibre and whole grains in diabetes management: Systematic review and meta-analyses
PLoS Medicine synthesis combines prospective cohorts of adults with type 1 or type 2 diabetes with 42 short trials (n≈1,789): higher fibre intake (~35 vs ~19 g/day in cohort dose narrative) linked to fewer deaths per 1,000 over follow-up; trials pooled lower HbA1c, fasting glucose, insulin resistance, lipids, weight, BMI, and CRP versus lower-fibre comparators with high heterogeneity.
Design
- Cohorts: two multicountry cohorts (~8,300 adults with T1D or T2D; ~8.8 y mean follow-up)
- Trials: 42 controlled trials (n ≈ 1,789) increasing fibre without bundled lifestyle coaching arms (per inclusion rules)
Mortality (cohort dose narrative; abstract)
Comparing ~35 g/day vs ~19 g/day dietary fibre: ~14 fewer deaths per 1,000 participants over study duration (95% CI 4–19) with dose–response language in abstract.
Trial pooled signals (abstract examples)
- HbA1c: MD −2.00 mmol/mol (95% CI −3.30 to −0.71; 33 trials)
- Fasting glucose: MD −0.56 mmol/L (−0.73 to −0.38; 34 trials)
- HOMA-IR: MD −1.24 (units as reported; 95% CI −1.72 to −0.76; 9 trials)
- Body weight / BMI / lipids / CRP: additional pooled benefits reported with high heterogeneity—inspect forest plots before translating to individual care.
Evidence hygiene
GRADE and meta-regression identify baseline fibre, region, and diabetes inclusion as drivers—do not substitute for medication titration or renal diet rules without clinicians.
Publication
Reynolds AN, Akerman AP, Mann J. PLoS Med. 2020 Mar 2;17(3):e1003053. PMID 32142510.
Outcomes
- Prospective cohort dose narrative: ~14 fewer deaths per 1,000 participants when comparing ~35 g/day vs ~19 g/day fibre intake over mean ~8.8 y follow-up (95% CI 4–19 fewer deaths).
- Trials meta-analysis: HbA1c MD −2.00 mmol/mol (95% CI −3.30 to −0.71; 33 trials) and fasting glucose MD −0.56 mmol/L (95% CI −0.73 to −0.38; 34 trials) with higher fibre vs lower-fibre comparators (Reynolds et al. 2020).