Infant Formulas: Safe Alternatives to Breast Milk in Many Situations

FACULTY:

W. Steven Pray, PhD, DPh
Bernhardt Professor, Nonprescription Products and Devices
Southwestern Oklahoma State University, College of Pharmacy
Weatherford, OK

FACULTY DISCLOSURE STATEMENTS:

Dr. Pray has no actual or potential conflict of interest in relation to this program.

U.S. Pharmacist does not view the existence of relationships as an implication of bias or that the value of the material is decreased. The content of the activity was planned to be balanced, objective, and scientifically rigorous. Occasionally, authors may express opinions that represent their own viewpoint. Conclusions drawn by participants should be derived from objective analysis of scientific data.

ACCREDITATION STATEMENT:

Pharmacy
Postgraduate Healthcare Education, LLC is accredited by the Accreditation Council for Pharmacy Education as a provider of continuing pharmacy education.
Program No.: 0430-0000-10-003-H04-P; 0430-0000-10-003-H04-T
Credits: 2.0 hours (0.20 ceu)

TARGET AUDIENCE:

This accredited activity is targeted to physicians, physician assistants, nurse practitioners, registered nurses, registered dietitians, pharmacists, and pharmacy technicians.

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DISCLAIMER:

Participants have an implied responsibility to use the newly acquired information to enhance patient outcomes and their own professional development. The information presented in this activity is not meant to serve as a guideline for patient management. Any procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this activity should not be used by clinicians without evaluation of their patients’ conditions and possible contraindications or dangers in use, review of any applicable manufacturer’s product information, and comparison with recommendations of other authorities.

GOAL:

The goal of this educational program is to inform the medical profession about various issues surrounding the use of commercially available infant formulas and to provide guidelines to allow professionals to more appropriately assist patients in the selection and use of an appropriate infant formula.

OBJECTIVES:

After completing this program, participants should be able to:

1. Recognize the optimum nutrition for infants through the first year of life—breast milk;*
2. Describe the role of formulas as adequate substitutes for term infants whose mothers cannot or choose not to breast-feed;*
3. Review regulations ensuring infant formula quality and safety;*
4. Discuss the myths and misconceptions associated with infant formulas, especially “generic” formulas;* and
5. Describe guidelines to assist patients in selecting and using the most appropriate infant formula.

*Also applies to pharmacy technicians.

The individual considering the use of an infant formula may notice that pharmacy shelves are fully stocked with an overwhelming array of products.¹ Many appear similar, to the uninformed eye, yet they are often radically different in respect to their ingredients, intended uses, and benefits.² It is critical to choose the appropriate product for each infant and the advice and assistance of a medical professional who is fully aware of the differences among formulas can be invaluable when making such a decision.

Breast-feeding and the Benefits of Breast Milk
Virtually all medical authorities recognize that human breast milk is the optimal nutritional resource for infants.^3-5 While there are a few exceptions, breast milk is best for normal newborns, premature newborns, and those with medical illnesses.

The Centers for Disease Control and Prevention (CDC) and the Health Resources and Services Administration (HRSA) cosponsor an initiative known as Healthy People 2010, designed to identify the most significant preventable threats to health and to establish national goals to reduce the threats. One of the goals is to improve the health and well-being of infants. These agencies plan to increase the proportion of mothers who choose to breast-feed their babies in the early postpartum period to 75% and to increase those who breast-feed infants aged 6 to 12 months to 50%.⁶ In a report card on the project, the CDC noted that the national percentage of women who have spent some time breast-feeding their babies is 73.9%, which is close to the 75% target.⁷ States with the lowest rates are mostly clustered in the Southern and eastern seaboards (e.g., 48.3% in Mississippi and low rates in Kentucky, Louisiana, Alabama, West Virginia, Tennessee, Georgia, Arkansas, and South Carolina). States with highest rates tend to cluster in the west, such as Utah (92.8%), Oregon, Washington, California, and outside the boundaries of the continental United States (U.S.) (Alaska and Hawaii).⁷

Breast-feeding has numerous advantages in comparison with infant formulas. For instance, breast milk contains all the nutrients necessary for the optimal growth and development of a normal infant.³ Breast milk also contains nutrients not found in formula, such as immunoglobulins.⁸ In addition, maternal circulation delivers antibodies to the fetus that provide protection against infection for 4 to 6 months; after that time, the infant receives antibodies via breast milk.³

The composition of human breast milk is not constant. Rather, its nutrient profile changes radically from early lactation to the final stages of breast-feeding.⁹ The exact mix and its gradual changes have not, yet, been duplicated with commercial formulas and this may be the reason for the differences in growth patterns between breast-fed and formula-fed infants.

Breast milk is easy to digest and moves through the digestive system more rapidly.³ It may reduce the risk of certain medical conditions.^3,10-12

In a landmark study, investigators prepared a report for the U.S. Department of Health and Human Services about the effects of breast-feeding on short-term and long-term infant and maternal health outcomes in developed countries.¹⁰ In preparation, they screened more than 9000 abstracts. They concluded that a history of breast-feeding was associated with a reduction in the risk of acute otitis media, nonspecific gastroenteritis, severe lower respiratory tract infections, atopic dermatitis, asthma (in young children), obesity, type 1 and type 2 diabetes, childhood leukemia, sudden infant death syndrome, and necrotizing enterocolitis.

The benefits of breast-feeding can endure for years.¹³ A history of being breast-fed for at least 15 weeks reduces the risk of respiratory infections in children up to the age of 7 years.¹⁴ Adults who were breast-fed have lower mean total cholesterol and low-density lipoprotein (LDL) cholesterol levels than those fed formula.¹² Some authorities report that breast-feeding can reduce the risk of diarrhea and cardiovascular disease.^3,14 There are reports that infants who are breast-fed have higher intelligence quotients (IQs), although this is debated.¹⁴

In recognition of the benefits of breast-feeding, the percentage of individuals who have chosen to breast-feed has risen over the years. In developing countries, the proportion is now over 90%; and in industrialized nations it is estimated to be between 50% and 90%.¹¹ In correlation with these increases, the duration of time to continue breast-feeding has also lengthened.

Situations in Which Breast-feeding Is Not an Option
Breast-feeding has the appropriate nutrients to support an infant’s first 12 months of life, but it may be extended for a longer period, if desired.³ There are several situations in which breast-feeding is not preferable or possible.

Some of the individuals who intend to breast-feed cannot do so because the supply of breast milk is inadequate as a result of maternal medical problems that occasionally occur (e.g., breast abnormalities, surgery). Further, some babies do not develop an efficient suckling reflex when presented with the breast; in this case, bottle feeding may be more easily mastered by the infant.³

It is important in some situations, or for certain patients, to be able to quantify the exact amount of nutrients the baby has ingested. These people may opt to pump the breasts and administer measured amounts. Those who do not wish to pump may find that infant formula is preferable because more precise measurements of nutrient intake are possible.

Many individuals who wish to breast-feed are taking medications. This is a realistic concern because certain medications are known to pass to the infant through breast milk.³ Medications that do so include cimetidine (e.g., nonprescription Tagamet HB 200), cyclophosphamide, lithium, gold salts, methotrexate, metronidazole (e.g., Flagyl), cyclosporine, and bromocriptine. The ability of most other medications to pass through breast milk has been inadequately studied. For this reason, patients taking almost any medication (especially those who must receive maintenance medications for chronic medical conditions) are best advised to consult with their physician before breast-feeding, minimizing risk for both their infant and themselves.

Some caregivers are forced by financial circumstances or through their personal preference to return to work while the child is still in the infant stages of development.³ If breast-feeding during breaks is not an option or pumping is not desirable, infant formula may be the optimal method of supplying infant nutrition.

Smokers who wish to breast-feed may consider their breast milk contaminated or unclean because of the nicotine residues that can reach the baby.¹⁵ Rather than smoking cessation, which is the far healthier choice, they may opt for the formula because they perceive it to be cleaner in comparison with their breast milk.

Infant Formula: General Points
Infant formulas do not duplicate the components of breast milk exactly; indeed, this would be impossible because the exact composition of breast milk has not yet been fully established. Rather, the goal of infant formula is to match the function of breast milk in regard to meeting the infant’s nutritional needs. Infant formulas have been proven to be a realistic and safe alternative to breast milk after a long period of use and with hundreds of millions of infant users.³ There is no set, immutable recipe for infant formulas. With the passage of time, new technologies emerge and new ingredients gain credibility.

Infant formula is more difficult to digest than breast milk and moves more slowly through the digestive system.³ Thus, babies fed on formula are able to go longer intervals between feedings.

When an infant is fed via bottle and formula, others may shoulder part of the responsibility, affording the main caregiver more time to rest and recuperate. In addition, allowing all family members to feed the baby and participate in daily care promotes their bonding with the child.³

Infant formulas generally include all the necessary nutrients, so there would be no need to provide additional nutrients.¹⁶ One exception to this rule is for babies who are fed a low-iron formula. In these cases, the child should be given iron, especially after the baby reaches 4 months of age.

Health care professionals occasionally field questions about generic (not brand name) infant formulas. This label has been misapplied to products from both reputable manufacturers with trade names that are relatively unfamiliar and to store brands or private-label brands. As explained by the FDA, “All infant formulas marketed in the U.S. must meet the nutrient specifications listed in FDA regulations. Infant formula manufacturers may have their own proprietary formulations, but they must contain at least the minimum levels of all nutrients specified in FDA regulations without going over the maximum levels, when maximum levels are specified.”¹⁶ Thus, the notion of generic formulas reflects an incomplete understanding of the rigorous controls to which all infant formula manufacturers must adhere. Patients will realize an economic benefit after the purchase of store brand or private-label brand infant formula, a cost savings that may be as high as 50%, depending on use.

Extra care should be taken to ensure the baby is not fed expired, degraded, or counterfeit formula.¹⁶ Caregivers must purchase infant formula at reputable suppliers only, taking care to avoid gray market sources, including flea markets, garage sales, and large-scale clearance outlets (e.g., fire-sale or water-damage stores) that refuse to provide quality assurance. If the expiration date has been erased, obliterated, covered up, relabeled, or altered in any way, the product should be avoided. Any suspicious or altered label is cause for concern. For example, a product that contains cow’s milk could be falsely labeled as milk-free, endangering the health of the infant. Any change in taste, smell, consistency, or color should initiate a prompt return of this product to the seller. All manufacturers’ lot numbers and the expiration dates on cans from the same case should match, and the data on the cases must match the labels on the cans packaged within.¹⁶ Cans should be free of dents, rust, bulges, leaks, and any other external sign of stress or damage.¹⁷ Once purchased, formula should be immediately stored in a cool, indoor location, as opposed to garages, outdoor storage buildings, or vehicles.

Caregivers may ask health care professionals about the safety of marketed infant formulas, referring to the 2008 outbreak of melamine-tainted infant formula suspected of causing 230,000 children to develop urinary stones and at least 6 deaths.^18,19 People should be reassured that this formula was distributed in China and other nations and that this has not occurred in the U.S. because of the stringent manufacturing controls required by the laws that govern the development of infant formulas. 

If caregivers suspect a problem or illness has been caused by an infant formula, they should contact the FDA, either by phoning the FDA Medwatch hotline (1-800-FDA-1088) or by completing the online form at https://www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm.¹⁶

Infant Formula and Regulatory Issues
Infant formula is a category of foods often used as the sole source of nutrition by a vulnerable population during their critical growth/development period. It is defined by federal law as, “a food which purports to be or is represented for special dietary use solely as a food for infants by reason of its simulation of human milk or its suitability as a complete or partial substitute for human milk.”¹⁶ Infants are defined in federal regulations as those not more than 12 months of age.¹⁶

Before infant formulas became commercially available, parents attempted to create infant formulas from scratch and some misguided parents may still feel capable of creating formula themselves. The Food and Drug Administration (FDA) and the American Academy of Pediatrics (AAP) both recommend strongly against this practice.³ It is simply not possible to duplicate the manufacturing process and to abide by the exacting standards to which manufacturers must adhere. If the parent fails to cook and process the product appropriately, renal damage may result³; nutritional imbalances may also result.¹⁶

Infant formulas are manufactured as a food, according to all requirements found in the Federal Food, Drug, and Cosmetic Act. They are regulated by the Center for Food Safety and Applied Nutrition (CFSAN) section of the FDA. Infant formula is “…often used as the sole source of nutrition by a vulnerable population during a critical period of growth and development.”¹⁶ Infant formula must meet federal nutrient requirements. The only ingredients that may be used in the manufacture of formula are those generally recognized as safe and effective and specifically appointed for use in the production of formula. For instance, ready-to-feed formulas and those supplied as liquid concentrates usually contain such ingredients as lecithin, carrageenan, monoglycerides, and diglycerides to help prevent the product from separating during its shelf life.¹⁶

Ingredients and Nutrient Content of Commercially Available Infant Formulas
Commercially available infant formulas are supplied as both liquids that are ready to use and liquid concentrates or powders that require dilution or reconstitution prior to administration. An important step in clarifying these infant formulas, for professionals and consumers alike, is to examine them from different aspects, such as their ingredients and nutrients.

Infant formulas contain water, carbohydrates, fat, protein, vitamins, minerals, and other ingredients. FDA requirements specify minimum amounts of 29 separate nutrients and the allowable maximum amounts for 9 of the nutrients.¹⁶ Manufacturers usually set nutrient amounts that safely exceed the FDA minimums (without exceeding the maximum levels) and this practice allows the formula to meet its label claims up to its expiration date.¹⁶ The requirements may be altered to produce a special class of products known as exempt formulas, which are legally defined as “…an infant formula intended for commercial or charitable distribution that is represented and labeled for use by infants who have inborn errors of metabolism or low birth weight, or who otherwise have an unusual medical or dietary problem.”^16,20 Manufacturers must meet all legal requirements prior to marketing any type of formula, and they must notify the FDA prior to marketing a new type of formula.¹⁶

Water
Ready-to-use formulas are a relatively simple option to consider. Liquid and powder concentrates must be prepared and administered exactly as directed. Whether the formula is ready-to-use or made from concentrate, it is approximately 85% water.³ Individuals may purposely add too much water to concentrates or dilute ready-to-feed formula in an attempt to save money.^3,21 They may also feed the baby water in addition to formula. Either practice can result in water intoxication, which may lead to hyponatremia, irritability, coma, or permanent brain damage. In contrast, some may add too little water when preparing formula from concentrate and administration of the resulting hypertonic formula can lead to diarrhea, dehydration, renal failure, gangrene of the legs, and coma.³

The water used for dilution/reconstitution of infant formulas may be drawn from the household tap; but caregivers are instructed to bring it to a boil and keep it at that point for one minute or as directed on the formula label.¹⁶ Commonly sold bottled waters are not guaranteed to be sterile and should not be used for dilution/reconstitution without boiling. Some stores sell bottled water designed to reconstitute infant formula powders or to dilute liquid concentrates. Unless these bottled water products are clearly labeled as sterile, they should also be boiled as directed above.

Carbohydrates
Carbohydrates are a major source of energy for an infant’s brain, muscles, and other tissues. Lactose is the standard carbohydrate in milk-based formulas and lactose-free formulas contain such carbohydrates as glucose polymers, sucrose, corn syrup solids, tapioca starch, and modified cornstarch.³

Proteins
Proteins serve a dual purpose: they are amino acids, which are the building blocks for growth, and they are also an energy source. Approximately 10% to15% of infants’ energy needs are met through the protein in breast milk.³ Most milk-based formulas contain casein and whey as their protein sources. Soy isolate is the protein in formulas intended for infants with special medical needs (see below).

Fats
Fat is critical for the development of a healthy baby, supplying a major part of the total daily caloric requirements. Most formulas supply fat as corn oil, soy oil, safflower oil, and coconut oils, but predigested fats known as medium-chain triglycerides (MCT) may be preferable for infants with certain medical problems.

ARA/DHA
 When manufacturers create a specific product’s lipid/fatty acid profile, they may focus their efforts on a certain ratio of long-chain polyunsaturated fatty acids known as arachidonic acids (ARA) and docosahexaenoic acids (DHA).^3,16 These fatty acids occur naturally in breast milk, but are not present in conventional infant formulas.² As a result, formula-fed infants have a lower concentration of these fatty acids in their blood than those ingesting breast milk.¹⁶ Early clinical studies suggested that these fatty acids might provide a short-term improvement in the visual function and neural development of infants.^3,16,22 As a result of those studies, manufacturers began to supplement some formulas with these ingredients in 2002.¹⁶ Additional research, performed more recently, failed to confirm the promise of the earlier studies, demonstrating no effect on the infant’s growth and yielding mixed results in the areas of improved cognitive and visual development.^11,16 The inconsistent results of studies leaves the door open for further research. Products supplemented with these fats include Nutramigen^® AA^® Lipil^® (Lipil is a trade name for a specific, proprietary blend of DHA/ARA; Mead Johnson & Company).²³

Vitamins and Minerals
Infant formulas generally contain the optimal level of vitamins and minerals recommended for a healthy baby; supplementation with vitamins should only be advised by a physician or other medical prescriber. Likewise, minerals are not necessary when standard products are chosen. However, there was once a controversy over the amount of iron needed in infancy, which prompted manufacturers to produce both a low-iron and a high-iron formula.³ The controversy has since been resolved in favor of all infants receiving normal iron products and the FDA and the AAP have advised against the use of low-iron formulas.^2,3 Some caregivers request low-iron formulas because of the perception that iron causes instances of constipation, diarrhea, vomiting, and colic.¹⁷ This is a misperception, as iron-fortified formulas do not cause a greater incidence of these problems. Parents should be persuaded to choose iron-fortified formulas instead of low-iron products. Despite these recommendations, a few low-iron formulas are still available (e.g., Similac^® PM 60/40 Low-Iron Formula). (Similac^® PM 60/40 is generally used for special conditions, usually renal, and not recommended for most infants because of low calcium phosphate levels.)

Prebiotics and Probiotics
Prebiotics are short-chain carbohydrates intended to support growth of beneficial organisms in the gastrointestinal tract by selectively encouraging beneficial bacteria to proliferate.^11,24,25 Prebiotics include such substances as inulin, fructooligosaccharides, and galactooligosaccharides.¹⁴ The body is unable to digest the prebiotics, allowing them to reach the colon in whole form. Supporters allege that ingesting prebiotic-fortified infant formula causes the stool cultures and its consistencies to be closer to those of breast-fed infants.¹⁴ One product utilizing this formula for administration to full-term infants is Enfamil^® Premium^® Lipil^® with Triple Health Guard^®. This milk-based product contains a prebiotic carbohydrate consisting of short galactose chains ending in glucose (i.e., galactooligosaccharide), synthesized from lactose.

Formulas may also include probiotics, strains of living organisms such as Lactobacilli that reach the intestine in an active state after ingestion and are, therefore, suspected of conferring specific health benefits, e.g., increased bowel health.^11,26 Both types of ingredients are purported to reduce the risk of infection, atopic disease, and allergies, and to prevent respiratory-tract infections, necrotizing enterocolitis, and rotavirus-induced diarrhea; but further research is needed to confirm these assertions.^14,27-30 Formulas containing probiotics include NESTLÉ^® GOOD START^® Protect PLUS^® (with Bifidus BL).

Carnitine and Taurine
Carnitine must be added to all infant formulas to aid in fat oxidation.¹¹ It is found naturally in formulas prepared from human milk and cow’s milk but must be added to soy-derived formulas. The role of taurine is less clear and the U.S. does not specify a minimum amount. It is often added to formulas to help prevent retinal abnormalities seen in patients administered taurine-free total parenteral nutrition on a long-term basis.¹¹

Nucleotides
Nucleotides are found in breast milk, and are the fundamental building blocks of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA), as well as adenosine-5’-triphosphate (ATP).¹⁷ Their addition to infant formula may aid in the proper development of the gastrointestinal tract and enhance overall immune function.

Milk-Based Formulas
Milk-based formulas are the first major class of infant formulas.³ The cow’s milk base supplies lactose as the carbohydrate³⁰; in addition, these formulations also contain cow’s-milk protein, which is a potential source of allergic reactions. They are supplemented with vegetable oil, vitamins, minerals, and iron. These formulas deliver adequate nutrition for a large number of healthy, full-term babies. They are generally considered the products of choice when formula is preferable, when breast-feeding is not an option, or when breast-feeding is terminated prior to the age of 12 months.¹ Such products include Bright Beginnings^® Milk-Based Infant Formula, Similac^®, Enfamil^®, and NESTLÉ^® GOOD START^®. The products can be considered interchangeable.²

Milk-based formulas are available both in products intended for full-term infants and in those more suitable for preterm infants. Those intended for full-term infants generally contain 20 kcal/ounce. Formulas for preterm infants will be discussed under the specialty formulas heading below.

Milk-based formulas are also available as an organic formulation produced by utilizing cows fed only organic feeds, and without exposure to pesticides, added growth hormones, or antibiotics. One such product is Bright Beginnings^® Organic Milk-Based Infant Formula, with added DHA and ARA.

Soy-Based Formulas
Soy formulas are another major formula classification, comprising about 25% of formulas purchased in the U.S.² These products include soy protein isolate, made from soybean solids, as their major protein source (supplemented with taurine, methionine, and carnitine), as well as vegetable oils (e.g., sunflower, safflower, soy, palm, coconut) to supply fat, and corn syrup solids, cornstarch/glucose polymers, and/or sucrose as their carbohydrate sources.^3,17,31 Products in this category include Similac^® Isomil^®, Similac^® Isomil^® Advance^®, Enfamil^® Prosobee^®, and NESTLÉ^® GOOD START^® Soy Plus™ and NESTLÉ^® ALSOY^®.

Soy-based infant formul as have traditionally been considered more appropriate than milk-based formulas in the following situations³:

• Lactose-intolerant infants
  
• Infants who have a documented IgE-mediated allergy to the whole protein in cow’s milk and to the milk-based formulas that use cow’s milk; perhaps 0.5% to 3% of infants fall into this category, experiencing abdominal pain, diarrhea, rectal bleeding, rash/eczema, wheezing, rhinorrhea, vomiting, extreme irritability, colic, and/or dyspnea when given milk protein^13,17,32-34; improvement is usually seen 2 to 4 weeks after discontinuation of a milk-based formula and the appropriate products should be continued until the infant is one year of age¹⁷
  
• Infants who have limits imposed on their ingestion of plant-derived foods
  

The role of soy-based formulas has recently been reconsidered by the AAP.³¹ The organization examined several issues, such as the presence of phytoestrogens and aluminum in soy formulas, as well as the severe gastrointestinal reactions to soy formula. Phytoestrogens are nonsteroidal estrogenic chemicals such as isoflavones from soy.³¹ Their effects on health are debated, but there is a potential effect on the infant’s immune and thyroid function, as well as its neurobehavioral and sexual development. Aluminum is present in soy formulas in far greater amounts than in breast milk, possibly affecting skeletal mineralization and leading to osteopenia in preterm infants.³¹ Infants may exhibit an age-dependent hypersensitivity to soy protein, causing such gastrointestinal problems as enteropathy with resultant malabsorption, enterocolitis with bloody diarrhea, and/or proctitis.

As a result of these issues with soy, in 2008 the AAP revised its previous recommendations to now restrict the use of soy formula except in infants with either galactosemia or primary lactase deficiency (extremely rare), or for those infants with a diet designed to avoid any animal-based products.³¹ In its 2008 clinical report, the AAP addressed the traditionally recommended use of soy products for those experiencing lactose intolerance as a result of the more common secondary lactase deficiency, as opposed to the rare primary lactose deficiency. The organization pointed out that these infants retain some lactase activity and seldom require a total lactose restriction; thus, the AAP suggested lactose-reduced cow’s milk formulas, as opposed to the lactose-free formulations, for the preferred alternative.

The AAP also suggested that a documented allergy to cow’s milk protein would be better addressed by the use of an extensively hydrolyzed protein formula, since many of those infants are also allergic to soy protein.³¹ Similar products will also be discussed in this article. Currently, soy-based formulas are not considered to be of any proven benefit in the instance of acute gastroenteritis, without a diagnosis of lactose intolerance, in colic, for allergy prevention in healthy or high-risk infants, and in infants with documented cow’s milk protein-induced enteropathy or enterocolitis.¹⁷

Lactose-Free Formulas
Lactase is the enzyme that breaks lactose into glucose and galactose, allowing it to be absorbed and used as a fuel source. Occasionally, babies are lactase-deficient, rendering them unable to use lactose as a fuel. Lactose intolerance is rarely inherited (i.e., congenital or primary alactasia), but it is commonly secondary to such problems as viral gastroenteritis. When an infant has experienced lactose intolerance, undigested lactose reaches the intestinal tract and causes diarrhea, bloating, cramping, and flatulence. Products marketed for the lactose-intolerant infant are derived from cow’s milk, but are either reduced-lactose or lactose-free formulations.³ They are also used provisionally for temporary relief of cramping and diarrhea in infants recovering from gastroenteritis or infectious diarrhea.³ They can be recommended for infants with galactosemia.² These products include Enfamil^® Gentlease^® Lipil^® and Similac^® Sensitive^®.

Specialized Formulas
Some infants require special formulas. They include infants who have genetic conditions (e.g., phenylketonuria), intestinal malformations, those who require special attention for electrolytes or other nutrients (e.g., fat malabsorption), cannot tolerate the whole protein in cow’s milk or have an allergy to it (e.g., casein and whey), or those who are experiencing a host of other medical problems (e.g., reflux; Table 1).^3,20

Preterm Formulas
Preterm infants are those born prior to 37 weeks of gestation.³⁵ Some specialty formulas were created for preterm infants because of their enhanced protein and calorie requirements, as compared with full-term infants.^2,36 In addition, these infants miss the third trimester of gestation, where the transfer of minerals from the mother would usually supply certain essential nutrients (e.g., calcium, magnesium, phosphorus), emphasizing the need for an enriched formula. Formulas marketed for preterm infants contain 24 kcal/ounce. These products include Enfamil^® Premature Lipil^® and Similac^® 24 Special Care^®. There are also some formulas marketed as being enriched, with a caloric density of 22 kcal/ounce, such as Bright Beginnings™ NeoCare™, Enfamil^® EnfaCare^® Lipil^®, and Similac^® NeoSure^®. Preterm products are marketed in ready-to-feed bottles. This makes them more expensive than enriched formulas, which are available in less expensive liquids or powders. Preterm babies usually are given preterm formula until approximately 34 weeks of gestational age, which correlates to an average weight of 3 pounds, 5 ounces.² Infants may then be transitioned to enriched formulas.

Predigested Formulas
Manufacturers have marketed products with partially hydrolyzed (predigested) protein formulas for decades, advertising them as more suitable for infants with gastrointestinal problems. The hydrolysis process breaks intact protein into smaller peptides whose molecular weight is generally less than 5000 daltons; other amino acids are added to improve the nutrient profile.^3,37-40 However, partially hydrolyzed formulas are not hypoallergenic and may cause reactions in infants with documented allergies.¹⁷ Examples of predigested formulas include Bright Beginnings^® Gentle^®, Enfamil^® Gentlease^®  Lipil^®, and NESTLÉ^® GOOD START^® Gentle PLUS™.⁴⁰

Extensively Hydrolyzed Formulas (Hypoallergenic Formulas)
Some babies have a true IgE-mediated allergy to cow’s milk protein, manifesting as blood in the stool or a mixture of dermatological, gastrointestinal, and/or respiratory symptoms.² Approximately 10% to 35% of those infants also have an allergy to soy protein, making it an unsuitable alternative.^2,3,31 For these infants, a group of products containing extensively hydrolyzed proteins may be a suitable choice since amino acids and small peptides are nonallergenic.^3,33,37 In these products, manufacturers subject the proteins to a hydrolysis process more rigorous than that of the predigested formulas, so that their average molecular weight is generally less than 3000 daltons.^17,40 In addition, they cost substantially more than the milk- and soy-based formulas¹⁷; further, the hydrolysis process greatly alters the taste, making them unappealing to some infants. Examples of extensively hydrolyzed (hypoallergenic) infant formulas include Enfamil^® Pregestimil^® Lipil^®, Simlac^® Alimentum^®, Enfamil^® Nutramigen^® Lipil^® with Enflora™ LGG, and NESTLÉ^® ALTHERA.⁴⁰ For example, ALTHERA is recommended for the infant with a cow’s milk protein and/or a soy protein allergy. The product consists of ultrafiltered, extensively hydrolyzed whey protein, which is composed of 80% small peptides and 20% amino acids; and it contains the other nutrients essential for optimal growth (e.g., fats, carbohydrates). A similar product, Nutramigen^® with Enflora™ LGG, supplies protein as an extensively hydrolyzed casein (supplemented with l-cystine, l-tyrosine, and l-tryptophan), along with the standard nutrients and also with the added probiotic Lactobacillus rhamnosus.

Amino Acid Formulas
Products characterized as amino acid formulations are not created from hydrolyzed protein; they are mixed from elemental amino acids.^32,33,37 One such product, EleCare^®, is comprised of 33% medium-chain triglycerides along with other components of a healthy diet. Being composed of elemental amino acids, this product is suitable for infants who can tolerate neither intact nor hydrolyzed proteins. It is also indicated for those with protein maldigestion, malabsorption, severe food allergies, short-bowel syndrome, eosinophilic gastrointestinal disorders, and gastrointestinal-tract impairment. Another such product is Neocate Infant, also containing 100% free amino acids.⁴⁰

Antireflux Formulas
Infants often experience episodes of gastroesophageal reflux, and premature infants are more prone to experience reflux than full-term babies.³⁵ The underlying abnormality is often the reduced resting muscle tone of the lower esophageal sphincter. One method of preventing reflux is to thicken the formula with rice starch; but such prethickened products as Enfamil^® A.R.^® Lipil^® and Similac^® Sensitive^® R.S. may also be helpful.² Their use has been demonstrated to reduce regurgitation.

Fat Malabsorption Products
Babies with fat malabsorption may benefit from fats that are broken-down into medium-chain triglycerides (MCT) (e.g., MCT Oil) as supplied in some specialty formulas (e.g., Enfamil^® Pregestimil^® Lipil^®).³

Other Products
For other specialty formulas, see Table 1. Most specialty formulas were created to meet the needs of infants with 1 or 2 very specific conditions, as illustrated in Table 1. However, one product is useful for a variety of relatively rare conditions. ProViMin^® (Abbott Nutrition) is a casein-derived formula that contains increased quantities of protein, vitamins, and minerals; but which is very low in carbohydrates and fat (e.g., 0.6 grams of carbohydrate and 0.4 grams of fat per 100 calories), allowing the caregiver flexibility in adding fat and carbohydrates as the patient’s individual condition dictates. This is suitable for such conditions as abetalipoproteinemia, hypobetalipoproteinemia, cholestasis, chylothorax, fatty acid oxidation defects, glutaric aciduria type II, hyperlipoproteinemia type I (fasting chylomicronemia), lymphangiectasis, and intestinal malabsorption of carbohydrates and/or fats.

Conclusion
In conclusion, it is not necessary to remain confused about the proper formula to recommend for your patients. Informed medical professionals can help patients navigate through the product maze and choose a formula that is appropriate for full-term infants, preterm infants, and those with a wide variety of metabolic or genetic conditions. In addition, it is reassuring to provide advice about the stringent manufacturing requirements for these products that ensure, when used as directed, these formulas are safe for the baby.

Sidebar: Breast Milk Fortification Product
The individual whose baby is premature or low birth weight and who wishes to breast-feed may be advised to express breast milk and place a fortifying supplement into the milk prior to administration. One such product, Enfamil^® Human Milk Fortifier, is a milk-based powder supplement that increases the levels of protein, energy, calcium, phosphorus, and other nutrients. The fat source is 70% medium-chain triglycerides and 30% soy oil. This product is not recommended for home use; it is used while the preterm infant is hospitalized. After discharge, caregivers may supplement breast-feeding with an enriched formula such as Similac^® NeoSure^®.

Case Study 1
An individual asks a health care professional for assistance with choosing a formula for her baby, 4 weeks of age. In response to questions, she answers that the baby girl was born at full-term, weighing 7 pounds and 6 ounces. She regained her birth weight by 2 weeks of age while breast-feeding and now weighs 8 pounds. This individual mentions that her sister’s baby, 8 months of age, was lactose intolerant and was placed on a special formula. She is considering making the switch from breast-feeding to a special formula for her baby’s health. She states that her child exhibits no symptoms of illness or distress during or after feeding.

Questions to Consider

1. What information should this new parent be given?
   
2. Is this child a candidate for soy formula?
   
3. Is this child a candidate for predigested formula?
   

Solving the Case
There is no identifiable reason to switch from breast milk to a special formula. If the child were lactose intolerant, she would have noticed such symptoms as diarrhea, flatulence, bloating, etc. All babies are unique, and her baby may never become lactose intolerant. She should be taught that breast milk is the optimal nutritional source for her baby and she should strive to continue the practice as long as practical. Thus, the child is not a candidate for either soy formula or predigested formula.

Case Study 2
Two individuals approach a health care professional with several containers of baby formula. They have noticed that there are price differences between them. They ask whether the less expensive formulas are as good as the more expensive, highly advertised brand-name products. They appear apprehensive about the use of a generic product they feel may be of lower quality; but they also describe their economic situation as dire.

Questions to Consider

1. Are there differences in quality between a more expensive formula and a store-brand formula?
   
2. Will they endanger their child’s health by making an economic decision to purchase a store-brand baby formula?

Solving the Case
The parents should be told that the concept of generic does not apply to infant formulas. All infant formula must be manufactured according to the strictest standards mandated by the FDA. Composition is similar, if not identical, between store brands and national brands. Store brands may also contain important nutritional additives not required by the FDA, including ARA and DHA or prebiotics and probiotics. For these reasons, in their particular situation, purchasing a store brand may help ease the economic burden on their family without endangering their infant’s health status.

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