<b><i>Background/Aims:</i></b> Human milk is considered the most suitable food for infants. The potential benefits of breastfeeding can be explained by the presence of different growth and neurotrophic factors in human milk. This study was designed to detect some biomarkers in human milk, which could be involved in the infant neurodevelopment and in the regulation of the maturation of neonatal intestine (brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), glial fibrillary acidic protein (GFAP), fibroblast growth factor 21 (FGF21), lysophosphatidic acid (LPA) and autotaxin (ATX)), and compare them on the basis of the consumption of iodine supplements or multivitamins. <b><i>Methods:</i></b> A prospective study included 37 healthy breastfeeding mothers, divided into 3 different groups: (1) 10 mothers who did not take supplements, (2) 17 mothers who took potassium iodine (KI) 200 µg/day and (3) 10 mothers who took a multivitamin supplement. <b><i>Results:</i></b> The concentrations of BDNF, GDNF, GFAP, FGF21, LPA and ATX in human milk were not significantly different in women who took a multivitamin or KI supplement compared with those who did not take any supplement. <b><i>Conclusions:</i></b> The presence of neurotrophic factors in human milk is neither modified by the consumption of supplements nor by their type.