Fortifier selection and dosage enables control of breast milk osmolarity.

Upon addition of the HMFs tested, BM osmolality increases significantly and keeps raising over time. All HMFs but the recently developed PreNAN FM85® at 4% exceed the AAP recommended threshold for osmolarity of 450 mOsm/kg. Addition of NSs to PreNAN FM85® at 4% significantly increases osmolality above 450 mOsm/Kg. Thus, using PreNAN FM85® at 5% may be preferable to adding nutritional supplements since nutritional recommendations by the ESPGHAN are reached with a lower increase in osmolality.