Infant Formulas

Breast milk is recommended for infants with CSID. An infant with CSID who is exclusively breastfed will not display symptoms until food or medication containing sucrose or starch is introduced. Unfortunately, there are circumstances where breast milk is not a feasible option. In this circumstance, parents need to know what infant formula is safe for an infant with CSID. Many parents/caregivers may change the infant’s formula several times before they find one that does not cause gastrointestinal symptoms. It is important to continue to find the formula that works best because a lack of growth using traditional formula may result in an infant being diagnosed with “failure to thrive.” A registered dietitian (RD) or pediatric gastroenterologist can help with formula choices.


Some infants with CSID are able to tolerate traditional infant formulas. CSID-friendly options (as of 2015) include Enfamil® Infant and Similac® Advance. Most infants with CSID should be able to tolerate formulas with lactose as the carbohydrate source. These formulas are the most economical and easiest to obtain.


Unfortunately, not all infants with CSID can tolerate traditional infant formulas due to gastrointestinal symptoms and/or weight loss. Some traditional and specialty infant formulas use sucrose or starches as their carbohydrate source and could produce symptoms in an infant with CSID. For this reason, there are two specialty formulas that have been shown to be successful for those patients with CSID who do not tolerate traditional formulas—3232A by Mead Johnson™ and No Added Carbohydrate Soy Infant Formula Base with Iron (RCFS®). All formula changes should be conducted under the advice of a physician and/or an RD.


3232A by Mead Johnson™

This is a protein hydrosylate formula that has to be mixed with an appropriate carbohydrate before consumption. This formula is indicated for use with infants with disaccharidase deficiencies or other disorders of carbohydrate malabsorption. Because 3232A is not nutritionally complete by itself, it is mixed with dextrose powder. Infants with CSID can tolerate dextrose. 3232A contains tapioca starch, so some infants diagnosed with CSID with significant problems with starch may not be able to tolerate this formula. If 3232A formula is used long-term, additional essential fatty acids supplementation should be considered. Infants on 3232A formula should be closely monitored by a physician and RD. It should be noted that 3232A formula does contain tapioca starch. For CSID patients that cannot tolerate starch, 3232A may not be tolerated.


No Added Carbohydrate Soy Infant Formula Base with Iron (RCF®)

This formula is indicated for use with infants who are unable to tolerate the carbohydrates found in traditional infant formulas. This product has no added carbohydrate, so appropriate carbohydrates must be added, which is usually added in the form of dextrose powder. This formula uses soy protein isolate to avoid symptoms of cow’s milk protein allergy or sensitivity. Infants on RCF® should be closely monitored by a physician and RD.


Due to the high cost of these alternative infant formulas, some insurance companies or WIC (Women, Infant, and Children program) may pay for them. Your physician can help you draft a letter of medical necessity to the insurance company in hopes of getting them to cover the cost of the formula. The letter of medical necessity should include the following information:

  • Patient’s name
  • Patient’s date of birth
  • Patient’s diagnosis of CSID
  • Current weight
  • Current length/height
  • Other relevant information
  • Request for insurance coverage or reimbursement for specialty formula