The Influence of Reducing Diets on Changes in Thyroid Parameters in Women Suffering from Obesity and Hashimoto’s Disease

Hashimoto's disease is listed among the most common endocrine causes of obesity. As treatment of obesity in women with Hashimoto's disease is frequently unsuccessful, the aim of this study was to evaluate the effectiveness of two different reducing diets and their influence on changes in thyroid parameters in female patients. A six-month observational/interventional study was performed on 100 women aged 18-65 years, previously diagnosed with Hashimoto's disease and obesity and receiving L-thyroxine. The women were randomly assigned to the test group (group A, n = 50) following elimination/reducing diets, and the control group (group B, n = 50) following reducing diets with the same caloric content (without elimination). Anthropometric and thyroid parameters were evaluated at the beginning, after 3 months and after 6 months of treatment. In both groups a significant decrease in BMI and body fat percentage was achieved, but in test group A the decrease in BMI and body fat percentage was significantly greater than in control group B (p < 0.002 and p = 0.026, respectively). Serum TSH (thyroid stimulating hormon) levels decreased significantly more in group A than in group B (p < 0.001). Group A exhibited significantly greater increases in fT4 and fT3 levels than the control group (p < 0.001) as well as significantly greater decreases in the levels anti-TPO (thyroid peroxidase) (p < 0.001) and anti-TG (thyreoglobulin) antibodies (p = 0.048). The application of reducing diets with product elimination was found to be a more beneficial tool for changing anthropometric and thyroid parameters in women suffering from obesity and Hashimoto's disease than classic reducing diets with the same energy values and macronutrient content.