Devina L. Willard, Lorraine S. Young, Xuemei He, Lewis E. Braverman, and Elizabeth N. Pearce

Iodine content of enteral and parenteral nutrition solutions

Endocrine Practice, July 2017, Vol. 23, No. 7, pp. 775-779.
doi.org/10.4158/EP161692.OR

ABSTRACT
Objective: Iodine is essential for thyroid hormone synthesis, and iodine deficiency may result in thyroid disorders including goiter and hypothyroidism. Patients on long-term enteral nutrition (EN) or parenteral nutrition (PN) may be at risk for micronutrient deficiencies. The recommended daily allowance for iodine intake is 150 μg for nonpregnant adults. However, there is no current consensus among scientific societies regarding the quantity of iodine to be added in adult EN and PN formulations. The objective of this study was to determine the iodine content of U.S. adult enteral and parenteral nutrition solutions. This study also aimed to determine whether adult patients in the United States who are receiving long-term artificial nutrition may be at risk for iodine deficiency.

Methods: Ten enteral nutrition solutions and 4 parenteral nutrition solutions were evaluated. The iodine contents of these solutions were measured spectrophotometrically and compared to the labeled contents.

Results: Measured and labeled EN iodine contents were similar (range 131–176 μg/L and 106–160 μg/L, respectively). In contrast, PN formulas were found to contain small, unlabeled amounts of iodine, averaging 27 μg/L.

Conclusion: Typical fluid requirements are 30 to 40 mL/kg/day for adults receiving either total EN (TEN) or total PN (TPN). Adults on long-term TEN likely consume enough servings to meet their daily iodine requirements. However, patients on long-term TPN would require on average 5.6 L PN/day to meet the recommended daily allowance of iodine. This volume of PN is far in excess of typical consumption. Thus, U.S. patients requiring long-term TPN may be at risk for iodine deficiency.

Abbreviations: EN = enteral nutrition; PN = parenteral nutrition; TEN = total enteral nutrition; TPN = total parenteral nutrition; UIC = urinary iodine concentration