Effects of Gluten-Free Diet in Non-Celiac Hashimoto's Thyroiditis: A Systematic Review and Meta-Analysis.

Edilene Maria Queiroz Araújo, Claubert Radamés Oliveira Coutinho-Lima, André Silva de Sousa, Lana Mércia Santiago de Souza, Helton Estrela Ramos, Bianca de Almeida-Pititto, Graziela De Luca Canto, Virginia Fernandes Moça Trevisani

Journal: Nutrients 2025;17(21):

PMID: 41228508

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Abstract

Background/Objectives: The gluten-free diet (GFD) may be anti-inflammatory in treating Hashimoto's thyroiditis (HT), but the studies are inconsistent. Methods: To determine the effects of the GFD in non-celiac HT, we included randomized controlled trials from the following databases: Cochrane Central, Embase, Lilacs, Medline, Scopus, and Web of Science. The study was registered at Prospero (no. CRD42024566034). The outcomes assessed included free triiodothyronine (fT3), free tetraiodothyronine (fT4), thyroid stimulating hormone (TSH), Anti-thyroid Peroxidase (TPO), anti-thyroglobulin (Tg), C-reactive protein (CRP), body weight (BW), body mass index (BMI) and adverse effects. Sensitivity, subgroup, meta-regression, bias risk, and evidence analyses' certainty were also assessed. Results: Only three studies were meta-analyzed, comprising 110 participants. The pooled data revealed the evidence was very uncertain about the effect of GFD compared to the control group on mean differences (MD) of TSH (MD -0.63 uIU/mL; 95% CI -1.63 to 0.36; p = 0.21), fT3 (MD -0.18 pg/mL; 95% CI -0.50 to 0.14; p = 0.28), fT4 (MD -0.33 ng/dL; 95% CI -0.89 to 0.23; p = 0.24), anti-Tg (MD -10.07 IU/mL; 95% CI -17.73 to -2.42; p = 0.010), anti-TPO (MD 76.19 IU/mL; 95% CI 46.86 to 108.51; p < 0.00001), CRP (MD -0.12 IU/mL; 95% CI -0.30 to 0.07), BW (MD -1.46 kg; 95% CI -6.70 to 3.77), and BMI (MD -1.80 kg/m2; 95% CI -3.30 to -0.31). The quality of evidence was rated as having serious methodological concerns to extremely serious imprecision. Conclusions: The GFD decreased anti-Tg and increased the anti-TPO levels, both significantly. There were no significant results on fT3, fT4, and TSH.

Address: Postgraduate Program in Evidence Based Medicine, Federal University of São Paulo (UNIFESP), São Paulo 04021-001, SP, Brazil.; Nutritional Genomics and Metabolic Dysfunctions Research and Extension Center (GENUT), Department of Life Sciences, State University of Bahia (UNEB), Salvador 41.150-000, BA, Brazil.; Postgraduate Program in Pharmaceutical Sciences (UNEB), Salvador 41.150-000, BA, Brazil.; Postgraduate Program in Interactive Processes of Organs and Systems, Institute of Health Sciences (ICS), Federal University of Bahia (UFBA), Salvador 40.110-902, BA, Brazil.; Nutritional Genomics and Metabolic Dysfunctions Research and Extension Center (GENUT), Department of Life Sciences, State University of Bahia (UNEB), Salvador 41.150-000, BA, Brazil.; Postgraduate Program in Evidence Based Medicine, Federal University of São Paulo (UNIFESP), São Paulo 04021-001, SP, Brazil.; Nutritional Genomics and Metabolic Dysfunctions Research and Extension Center (GENUT), Department of Life Sciences, State University of Bahia (UNEB), Salvador 41.150-000, BA, Brazil.; Health Sciences Center, Federal University of the Reconcavo of Bahia (UFRB), Santo Antônio de Jesus 44.430-622, BA, Brazil.; Postgraduate Program in Interactive Processes of Organs and Systems, Institute of Health Sciences (ICS), Federal University of Bahia (UFBA), Salvador 40.110-902, BA, Brazil.; Bioregulation Department, Institute of Health Sciences (ICS), Federal University of Bahia (UFBA), Salvador 40.110-100, BA, Brazil.; Department of Preventive Medicine (UNIFESP), São Paulo 04024-002, SP, Brazil.; Postgraduate Program in Evidence Based Medicine, Federal University of São Paulo (UNIFESP), São Paulo 04021-001, SP, Brazil.; Brazilian Centre for Evidence-Based Research, Federal University of Santa Catarina, Florianopolis 88.040-900, SC, Brazil.; Postgraduate Program in Evidence Based Medicine, Federal University of São Paulo (UNIFESP), São Paulo 04021-001, SP, Brazil.; Department of Medicine, University of Santo Amaro, São Paulo 04743-030, SP, Brazil.

DOI: 10.3390/nu17213437

MeSH Terms: Humans, Diet, Gluten-Free, Hashimoto Disease, Thyrotropin, Randomized Controlled Trials as Topic, C-Reactive Protein, Female, Autoantibodies, Body Mass Index, Thyroxine, Male, Triiodothyronine, Adult