A recent retrospective study (LF Gonzalez Ballesteros et al Bone 2017; 97: 287-92) of 17 centers in North America and Ireland (2014-2016) identified a frequent association between an elemental formula and idiopathic hypophosphatemia in infants and children.

Key findings:

• “Fifty-one children were identified at 17 institutions with unexplaned hypophosphatemia.  Most children had complex illnesses and been solely fed Neocate® formula products for variable periods of time.”
• “Hypophosphatemia was detected during evaluation of fractures or rickets.  Increased alkaline phosphatase activity”  was noted in nearly all cases.
• “Most all improved with addition of supplemental phosphate or change to a different formula product.”
• Median age was 3.0 years (range 0.2 years to 15.5 years).  Median duration of Neocate® was 1.3 years

Since the composition of the formula had adequate phosphate, the authors speculate that the “bioavailability of formula phosphorus may be impaired in certain clinical settings.” Interestingly, this report singles out Neocate® products, “although the possibility of hypophosphatemia may occur with other amino-acid based formulas cannot be excluded.” Neocate® infant has similar amounts of phosphorus as Elecare®: 82.2 mg of phosphorus per 100 kcal compared with 84.2 mg.

My take: In patients receiving exclusive amino-acid based formulas (especially Neocate®), it is probably worthwhile to periodically monitor phosphate, calcium, alkaline phosphatase and possibly other micronutrients.

College of Charleston