Endocrine Abstracts

Objective: Oxidative stress has been implicated in the pathogenesis of several immune-mediated disorders, including autoimmune thyroid disease. Aim of our study was to investigate the relationship between dietary habit and redox homeostasis, in relationship with thyroid autoimmunity.

Materials and methods: We enrolled 200 healthy subjects (173 F, mean age 35 ± 12). None of them was under any pharmacological treatment. Exclusion criteria: any infectious/inflammatory/autoimmune comorbidity, kidney failure, diabetes, cancer. In each subject, we measured; serum TSH, free thyroxine andanti-thyroid antibodies; plasma oxidative stress markers (Table 1). A validated questionnaire on dietary habits, evaluating the intake frequencies of food groups (meat, fish, cereals, fruits and vegetables, dairy products) was submitted to each participant.

Results: Among the 200 recruited subjects, 81 (71 F, mean age 38 ± 11 yr) were diagnosed with euthyroid Hashimoto’s thyroiditis (HT), the remaining 119 (102 F, mean age 33 ± 12 yr) served as controls. In HT subjects, AGEs, markers of oxidative stress, were significantly higher (P = 0.0001), and anti-oxidants GPX, TRX and TEAA lower (P = 0.02, P = 0.02, P = 0.002, respectively) than controls, clearly indicating a condition of oxidative stress (Table 1). In questionnaires, HT subjects reported higher intake frequencies of animal foods (meat P = 0.0001; fish, P = 0.002; dairy products, P = 0.030) compared to controls, that, in turn, reported higher intake frequencies of plant foods (legumes, P = 0.010; fruits and vegetables, P = 0.030). Stepwise regression models demonstrated a significant dependence of oxidative stress parameters from consumption of animal foods: meat dietary intake was associated with low levels of GPX (P = 0.048) and TRX (P = 0.007), and dairy products intake was associated to low levels of TEAA (P = 0.020).

Conclusions: The present study provides further evidence that oxidative stress increases in euthyroid HT. Moreover, it suggests a positive influence of low intakes of animalfoods on the oxidative/antioxidative balance, and a potential protective effect of such dietary habit towards oxidative stress-related disorders.

Table 1