Proteins are large molecules composed of one or more chains of amino acids linked by peptide bonds.  Hydrolysis refers to the action of breaking these large peptide bonds into their smaller components, amino acids.  Hydrolysis is what happens within our digestive system during the digestive process, this explains why hydrolyzed formulas are sometimes referred to as pre-digested.

Hypoallergenic formulas can be divided into two main categories:

1.  Casein Hydrolysate (Elemental) Formulas

Some would divide this category into two sections: partially hydrolyzed and extensively hydrolyzed formulas.  The difference clearly, is in the degree of hydrolysis (DH), which means how much each is broken down.

• Partially hydrolyzed (PHF) - A portion of the cow's milk protein in these has been broken down (hydrolyzed), however; some intact proteins still exist, making the potential for allergic reactions possible.  Although sometimes called hypoallergenic, they are not actually considered a true hypoallergenic formula.  Carnation Good Start is an example of this type of formula.
• Extensively hydrolyzed (EHF) - Most of the proteins in these formulas have been extensively broken down.  These can taste bitter and cost significantly more than standard formulas but have been proven to significantly lower the risk of allergic reactions to milk or soy proteins.

Listed below are extensively hydrolyzed formulas.

*The fat source and carb source in the liquid version appears in the chart, the fat source in the powdered version also includes corn oil and the carb source in the powdered version also contains dextrose.

**MCT-Medium Chain Triglycerides can help assure that infants with fat malabsorption receive an adequate energy supply. Medium chain triglycerides are more easily and rapidly hydrolyzed and absorbed than long chain fatty acids by infants with fat malabsorption.

The second category of hypoallergenic baby formula is:

2.  Amino Acid Based

Some babies have difficulty with even EHF's and require amino acid based formulas.  Amino acids are the actual molecular units that make up protein, or the building blocks of protein.  Breaking the proteins down to their basic chemical structure (completely pre-digested) makes amino acid based formulas the most hypoallergenic formulas available and are said to virtually eliminate the possibility of allergic reaction.  These are also used in babies with absorption disorders.

Reviewed By Dave Olson, MD
Fellow, American Academy of Pediatrics
Graduate University of Michigan School of Medicine