Effect of probiotics or prebiotics on thyroid function: A meta-analysis of eight randomized controlled trials

Study answer

What this study found

Overall, probiotics or prebiotics did not significantly change thyroid hormone measures in the pooled analysis. There was no significant effect on TSH (SMD -0.01, 95% CI -0.21 to 0.20, P=0.93), fT4 (SMD 0.04, 95% CI -0.29 to 0.21, P=0.73), or fT3 (SMD 0.45, 95% CI -0.14 to 1.03, P=0.43). In Graves’ disease, however, supplementation significantly reduced TRAb levels (SMD -0.85, 95% CI -1.54 to -0.15, P = 0.02; I2: 18%). The authors concluded that thyroid hormone effects were not significant overall, but TRAb reduction may indicate a potential benefit in Graves’ disease.

Study & population

Systematic review and meta-analysis of 8 randomized controlled trials enrolling 367 participants from China, Iran, and Italy.

Intervention

Eight randomized controlled trials evaluated oral probiotic, prebiotic, or synbiotic regimens in adults with thyroid disease or risk of thyroid dysfunction.

Key limitation

Evidence was limited to 8 trials with 367 participants and substantial variability in populations, interventions, and durations.

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Original abstract