Brazilian preschool children attending day care centers show an inadequate micronutrient intake through 24-h duplicate diet

•89% of children did not achieve a potassium adequate intake.•Calcium and selenium were the micronutrients with highest inadequate intake rates.•48% of children had a sodium intake higher than the tolerable upper level.•Overweight and obesity prevalence in the studied preschool group was 17%. Inadequate micronutrient intake in childhood harms growth and development, and it is related to increased rates of morbidity and mortality. The aim of this study is to evaluate the dietary intake and prevalence of inadequate micronutrient intake in preschool children (1–4 years old) attending two-day care centers. To assess children’s dietary micronutrient intake, 24-h duplicate diets (n = 64) were collected for one week-day, including everything the children ate and drank both at home and in kindergarten. Anthropometric measurements were carried out to evaluate the children’s nutritional status. The micronutrients copper, iron, calcium, magnesium, selenium, zinc, potassium, sodium, and manganese were determined by inductively coupled plasma mass spectrometry or graphite furnace atomic absorption spectrometry. Calcium and selenium were found with high inadequate intake rates: 50% and 42%, respectively, for children aged 1–3 years old, and 93% and 90% for children aged 4 years. Potassium was consumed in very low amounts, 13% and 5% of children aged 1–3 and 4 years old, respectively, achieved the adequate intake for the nutrient. Sodium intakes were excessive: 23% of the 1–3-year old and 42% of the 4-year-old children, respectively, had an intake higher than the tolerable upper levels. Regarding the nutritional status, overweight and obesity prevalence was 17%. Therefore, considering the damaging health effects for children of micronutrient deficiency and overweight and obesity status, it is necessary that government authorities be aware and update public policies and educational programs in order to promote healthy eating habits in early childhood.