Background: There is no effective treatment for children with subclin. hypothyroidism. The natural course of subclin. hypothyroidism shows a normalization rate of 41% for TSH (TSH). Objective: The thyroid needs (among others) iron, iodine, and vitamin A for a proper thyroid hormone synthesis. We hypothesize that with a dietary change, more children can normalize their TSH. Design: In this case-control study, 54 children aged 1-14 years with subclin. hypothyroidism were divided into a diet group and a control group. The diet consisted of green vegetables, beef, full fat milk, and butter. The diet was followed for at least 3 mo. A total of 27 patients comprised the diet group and 27 the control group. TSH, Free T4 (FT4), and Body Mass Index (BMI) were evaluated during the follow up. Results: By following this diet, TSH levels decreased significantly compared to when following the natural course. FT4 levels did not change during the follow up. The diet group realized a change of normalizing their TSH with a RR 2.8 (95% CI 1.45-5.61). There were no changes in BMI after following the diet. Conclusions: Even though our study population was small, we observed the association of a dietary change and normalization of TSH in children with subclin. hypothyroidism, without adverse effects.