ASSOCIATION BETWEEN A 6-WEEK ELIMINATION DIET AND INFLAMMATORY BIOMARKERS IN WOMEN WITH HASHIMOTO THYROIDITIS

Abstract

Background: Hashimoto thyroiditis (HT) is characterized by chronic autoimmune inflammation with elevated proinflammatory cytokines. Elimination diets have been proposed as adjunctive nutritional interventions to modulate immune responses, though evidence remains limited.

Objective: This retrospective case-control study examined associations between a 6-week elimination diet protocol and inflammatory biomarkers, particularly interleukin-6 (IL-6), in women aged 30–50 years with HT receiving stable levothyroxine therapy.

Methods: Medical records of 60 women aged 30–50 years diagnosed with HT were reviewed retrospectively. The case group (n=30) received a 6-week elimination diet (excluding gluten, dairy, soy, refined sugars, processed foods) alongside levothyroxine. Controls (n=30) received levothyroxine alone. Inflammatory biomarkers (IL-6, TNF-α, IL-1β), hematological indices (PLR, NLR, MLR), thyroid function, autoantibodies, vitamin D, and metabolic parameters were assessed at baseline and 6 weeks.

Results: At 6-week follow-up, the elimination diet group had significantly lower IL-6 levels compared to controls (6.95±2.35 vs. 9.47±4.13 pg/mL, p=0.01), with significant within-group reduction (p=0.01) versus no change in controls (p=0.48). The elimination diet group showed significant reductions in PLR (p=0.01), increases in vitamin D (p=0.01), decreases in insulin (p=0.01), and reductions in BMI (p=0.02). Both groups exhibited decreases in TSH and thyroid autoantibodies (anti-TPO, anti-TG) with no significant between-group differences. TNF-α and IL-1β remained unchanged in both groups.

Conclusion: In this retrospective analysis of women aged 30–50 years with HT, a 6-week elimination diet protocol was associated with reduced IL-6 levels and favorable changes in PLR, vitamin D, insulin, and BMI. The similar reductions in thyroid autoantibodies and TSH across both groups suggest these changes may reflect natural disease fluctuation, regression-to-mean, or pharmacological effects rather than dietary intervention. These findings should be interpreted cautiously due to the retrospective design and small sample size. Prospective randomized controlled trials are needed to establish causality and clinical utility.