Osmolality of elemental and semi-elemental formulas supplemented with nonprotein energy supplements

Background: Elemental and semi-elemental formulas are used to feed infants with short bowel syndrome, who may not be able to tolerate feeds of more than 310 mOsm kg^-1. The present study aimed to measure the osmolality of elemental and semi-elemental formulas at different concentrations, with and without the addition of nonprotein energy supplements. Methods: The osmolality of one elemental and three semi-elemental formulas was measured by the freezing point depression method at concentrations of 10, 12, 14 and 16 gper 100 mL, with and without 10% or 20% of additional calories, in the form of glucose polymers and medium chain triglycerides. Inter-analysis and intra-analysis coefficients of variation of the measurements were less than 3.9%. Results: The mean osmolalities of formulas reconstituted up to 12 g per 100 mL did not exceed 305.3 mOsm kg^-1, even with added energy supplements. The mean osmolalities of formulas at 14 and 16 g per 100 mL, with or without added energy supplements varied between 205.8 and 421.6 mOsm kg^-1. Conclusions: A comprehensive list of elemental and semi-elemental formulas at different concentrations, enriched or not with calories, is made available. This will enable professionals to customize feeds with the optimum composition, without exceeding the osmolality suggested for infants with short bowel syndrome.