Influence of Dietary Habits on Oxidative Stress Markers in Hashimoto's Thyroiditis

Abstract

Background: There is a growing awareness that nutritional habits may influence risk of several inflammatory and immune-mediated disorders, including autoimmune diseases, through various mechanisms. The aim of the present study was to investigate dietary habits and their relationship with redox homeostasis in the setting of thyroid autoimmunity. Materials and Methods: Two hundred subjects (173 females and 27 males; median age, 37 years) were enrolled. None were under any pharmacological treatment. Exclusion criteria were any infectious/inflammatory/ autoimmune comorbidity, kidney failure, diabetes, and cancer. In each subject, serum thyrotropin (TSH), free thyroxine, antithyroid antibodies, and circulating oxidative stress markers were measured. A questionnaire on dietary habits, evaluating the intake frequencies of food groups and adherence to the Mediterranean diet, was submitted to each participant. Results: Among the 200 recruited subjects, 81 (71 females and 10 males) were diagnosed with euthyroid Hashimoto's thyroiditis (HT); the remaining 119 (102 females and 17 males) served as controls. In questionnaires, HT subjects reported higher intake frequencies of animal foods (meat, p = 0.0001; fish, p = 0.0001; dairy products, p = 0.004) compared with controls, who reported higher intake frequencies of plant foods (legumes, p = 0.001; fruits and vegetables, p = 0.030; nuts, p = 0.0005). The number of subjects who preferentially consumed poultry instead of red/processed meat was lower in HT subjects than in controls ( p = 0.0141). In logistic regression analysis, meat consumption was associated with increased odds ratio of developing thyroid autoimmunity, while the Mediterranean diet traits were protective. In HT subjects, serum advanced glycation end products (markers of oxidative stress) were significantly higher ( p = 0.0001) than in controls, while the activity of glutathione peroxidase and thioredoxin reductase, as well as total plasma antioxidant activity, were lower ( p = 0.020, p = 0.023, and p = 0.002, respectively), indicating a condition of oxidative stress. Stepwise regression models demonstrated a significant dependence of oxidative stress parameters on consumption of animal foods, mainly meat. Conclusions: The present study suggests a protective effect of low intake of animal foods toward thyroid autoimmunity and a positive influence of such nutritional patterns on redox balance and potentially on oxidative stress-related disorders.

Serum Levels of Soluble Receptor for Advanced Glycation End Products Are Reduced in Euthyroid Children with Newly Diagnosed Hashimoto’s Thyroiditis: A Pilot Study

“…It has to be underlined that all our patients were euthyroid and, therefore, no alteration of oxidative stress parameters could be attributed to overt or subclinical hypothyroidism, since we decided to recruit only patients with euthyroid HT at diagnosis. The links between AGEs, sRAGE, and AOPPs and HT have been already investigated in adults [22, 31, 32]. In particular, significantly higher serum levels of AGEs and lower serum levels of sRAGE have been documented among HT patients than controls [22, 31, 32].…”

“…The links between AGEs, sRAGE, and AOPPs and HT have been already investigated in adults [22, 31, 32]. In particular, significantly higher serum levels of AGEs and lower serum levels of sRAGE have been documented among HT patients than controls [22, 31, 32]. In our study, we demonstrated that euthyroid children with HT had lower serum levels of sRAGE, notwithstanding that significant differences in AGEs, AOPPs, and AGEs/sRAGE have not been documented.…”

“…There is an increased evidence that dietary regimen might influence risk of autoimmune disorders either directly by increasing inflammation and altering immune (CD4+ effector and T regulatory cells) balance and intestinal microbiota composition, or indirectly through increasing fat mass and obesity [37]. Recently, a protective effect of low intake of animal foods toward thyroid autoimmunity and a positive influence of such nutritional patterns on redox balance and potentially on oxidative stress-related disorders have been demonstrated [32].…”

“…AGEs-RAGE/sRAGE interaction is involved in the pathogenesis of several diseases related to oxidative stress [29, 30], but scanty data are available concerning thyroid autoimmunity. Recently, increased levels of AGEs have been reported in adult individuals suffering from HT [31, 32]. No data are available on such oxidative stress parameters in pediatric HT patients.…”

The Influence of Oxidative Stress on Thyroid Diseases

“…Advanced glycation end products (AGE) are believed to be associated with the onset and progression of metabolic disorders, notably diabetes and obesity, due to their formation both through lipid peroxidation and glycoxidation reactions; that is, in response to an increased intake of simple carbohydrates [15,63]. Elevated levels are observed in ROS-damaged tissues, as the final product of peroxidation, making them markers of oxidative stress in the body [64]. Among DNA bases, guanine is the most easily oxidised, due to its relatively low redox potential.…”