concentrating / Fortifying feedings

Concentrating infant formula or fortifying expressed breastmilk is a common practice for increasing an infant's nutrient intake. While this is helpful for some infants, problems can arise when formulas are prepared improperly or there is not careful monitoring.

Risks associated with concentrated or fortified feedings can include (Oregon PNPG):

• dehydration due to excessive renal solute load (see below)
• hypervitaminosis
• intestinal blood loss
• allergenic properties
• improper nutrient composition
• improper bone mineralization
• insufficient fluid intake

Renal solute load is the amount of nitrogenous waste and minerals that must be excreted by the kidneys. When renal solute load exceeds the capacity of the kidneys, dehydration can lead to serious complications, including neurologic deterioration. Acute illness (especially febrile), increased water losses, and medical conditions can decrease an infant's ability to concentrate urine and excrete solutes.

Potential renal solute load (PRSL) is the concentration of solute provided by diet (if none were used for new tissue or lost through non-renal routes). Human milk has a PRSL of about 14 mOsm/100 kcal. Infant formulas typically have PRSL of 20-26 mOsm/100 kcal.

It has been suggested that an upper limit of 30-35 mOsm/100 kcal be used to decrease an infant's risk of hypertonic dehydration. (Fomon and Ziegler, 1999)

The Oregon Pediatric Nutrition Practice Group, Oregon Dietetic Association has developed a resource: Selecting and Concentrating Infant Formula: guidelines for healthcare professionals. 2005. Ordering information can be found at: http://www.eatrightoregon.org/pnpg/resources.htm