Objective: We have comprehensively evaluated an immunologic response to food antigens, mediated by immunoglobulin G (IgG) antibodies, on clinical aspects of Hashimoto's thyroiditis (HT).
Methods: IgG antibodies to 125 food antigens were measured in serum samples of 74 HT patients and 245 controls using microarray-based enzyme-linked immunosorbent assay (ELISA) test. We analyzed differences in IgG levels between two groups and evaluated correlations between food-specific IgG levels and HT-related clinical phenotypes (thyroid hormones/antibodies, symptoms of hypothyroidism, measures of body size and blood pressure) and food consumption in HT patients.
Results: We observed increased IgG levels to 12 different food antigens in either HT cases or controls, of which plum-specific IgG antibodies were significantly higher (p = 1.70 × 10-8), and almond-specific IgG antibodies were significantly lower (p = 8.11 × 10-5) in HT patients in comparison to controls, suggesting their possible roles in HT etiology or symptomatology. There was no significant correlation between any of 12 increased food-specific IgG antibodies, along with gluten-specific IgG, with clinically important phenotypes, such as thyroid hormones/antibodies or symptoms. Among other tested correlations, the most interesting is the negative correlation between coffee and tea combined IgG levels and number of symptoms, suggesting possible beneficial effect of tea and coffee on disease symptoms. We also found that food consumption is not correlated with IgG levels.
Conclusions: Distribution of food-specific IgG antibodies is comparable between HT patients and controls, with the exception of plum and almond. There is no evidence that increased food-specific IgG antibodies are associated with clinical aspects of HT. Clarification of biology behind formation of these antibodies is needed.
Keywords: Hashimoto’s thyroiditis; almond; food intolerance; food-specific IgG; gluten; hypothyroidism; plum.