Taking a rational approach to the choice of infant formula

August 1, 2001

Dissuade mothers from switching formulas unnecessarily and help them avoid disappointment by knowing how formulas differ and what constitutes genuine intolerance.

 

Cover article

Taking a rational approach to the choice of formula

Jump to:Choose article section... Overview: Infant formula use Standard cow-milk– based formula The newest cow-milk– based formulas Soy-based formulas When it makes sense to switch Breast is still best, but...

By Michael K. Georgieff, MD

After all is said, some mothers prefer formula to the breast for their baby. Standard cow-milk–based products suit most babies, but other options are more appropriate for some. Dissuade mothers from switching formulas unnecessarily and help them avoid disappointment by knowing how formulas differ and what constitutes genuine intolerance.

Many health organizations, including the American Academy of Pediatrics (AAP), endorse breastfeeding as the optimal source of infant nutrition during the first year of life.1 Nevertheless, more than half of infants in the United States receive infant formula by 2 months of age. By 6 months of age, fewer than 25% of infants are breastfeeding, either exclusively or with supplemental formula—far short of the 50% goal for this age set by the Healthy People 2000 initiative and the AAP.

The mother who chooses to feed her child infant formula has several options. The mainstay of these formulas is cow milk, but soy-based formulas and cow-milk formulas in which the protein is hydrolyzed constitute a significant percentage of the formula that is sold. Soy-based formulas account for 25% of elective formula sales in the United States (this figure does not include formula supplied by the Special Supplemental Nutrition Program for Women, Infants, and Children); hydrolyzed casein or whey formulas account for a smaller percentage of sales.

This utilization pattern is based in part on historical precedent because the original modern-era formulas, introduced in the 1920s, were cow-milk based. Other formulas were created largely to address concerns over real or perceived intolerance to cow-milk– based formulas, including cow-milk protein allergy, primary or secondary lactase deficiency, and colic. These concerns continue to drive many decisions by physicians and parents to switch formulas. By knowing the pros and cons and characteristics of available formulas, pediatricians can help mothers make a good initial choice and address the advisability of any proposed change.

Overview: Infant formula use

The popularity of infant formula in the United States is not new; indeed, human milk substitutes have been around since ancient times. The percentage of infants receiving infant formula exclusively reached a peak in the late 1960s and 1970s, when only about 40% of women chose to nurse their infant. Formula use decreased slightly in the past two decades, and now more than 60% of women choose to breastfeed their infant from birth. Many of these infants are, ultimately, fed a mixed diet of human milk and formula, however.

Why do mothers feed their infant formula? Most often, it is simply because they—not their baby—prefer formula to the breast. The AAP believes that a variety of reasons account for this preference: a lack of breastfeeding education, persistence of cultural norms, lack of perinatal and postdischarge lactation support, and failure of health-care providers to promote breastfeeding in their practice.1 Many women choose to supplement their breastfeeding regimen with infant formula as a way of ensuring that fathers, other family members, and day-care providers can help care for the infant. Mothers could use pumped breast milk for this "supplemental bottle feeding," but many women prefer infant formula because it is convenient and they are confident it is nutritionally adequate and safe.

There are other reasons for choosing formula over breast milk. A medical contraindication to human milk is one reason; among the few such contraindications are galactosemia, certain maternal medications and chemotherapeutic agents, and, in the United States, maternal HIV infection.1 The failure of human milk to sustain growth is another reason: Although this is a rare event in term infants, a small preterm infant may require supplementation with formula after discharge.2

The Food and Drug Administration (FDA) tightly regulates infant formulas produced in the United States. The FDA is greatly interested in ensuring the safety of these products, given the significant modifications to raw cow milk necessary to meet the nutritional needs of the human infant. The Infant Formula Act of 1980, modified in 1986, specifies the maximum and minimum allowable concentrations of certain, but not all, nutrients in formulas intended for routine use in term infants. The FDA is considering a further modification to stipulate maximums and minimums of all nutrients in term and preterm infant formulas.

Standard cow-milk– based formula

The most commonly used standard cow-milk–based formulas marketed in the United States are remarkably similar to each other. Most infants tolerate these formulas.

What milk formulas contain. Standard formulas provide 67.6 kcal/dL (approximately 20 kcal/oz), with 43% of calories as carbohydrate, close to 50% as fat, and the remainder as protein.3 The carbohydrate source is lactose, and the fat source is vegetable oil because infants do not tolerate high concentrations of cow-milk fat. The protein source is nonhydrolyzed cow-milk protein, which is predominantly casein. Whey, the dominant protein in human milk, is thought to be more digestible than casein protein because it has lower curd tension. Some manufacturers therefore have produced formulas that have a higher whey content than cow milk does.

The potential renal solute load and osmolality of these formulas are higher than those in human milk. This is not a health concern in the well infant, but is potentially an issue in an infant with diarrhea and dehydration or with renal disease.

Cow-milk formulas contain enough vitamins and minerals to ensure that a healthy infant who consumes a standard amount does not need vitamin or mineral supplements. The formulas are available with and without iron supplementation. The AAP strongly recommends the iron-supplemented form (10 to 12 mg of iron per liter) to minimize the possibility of iron deficiency, which is harmful to brain development and organ function.4,5 The concentration of iron in the supplemented formulas appears to be more than enough to ensure that >95% of infants consuming the products receive sufficient iron, assuming no gastrointestinal blood loss.

Low-iron formulations, defined by the FDA as containing <6.7 mg/L of iron, once contained <1.5 mg/L of iron, resulting in an unacceptably high rate of iron deficiency and iron-deficiency anemia.6 Over the past five years, formula manufacturers have increased the amount of iron to 4–5 mg/L. With no clear-cut medical indications for a low-iron formulation, however, the AAP has called for these products to be taken off the market.4

Intolerance to cow-milk formulas. Some formula-fed infants do not tolerate standard cow-milk–based infant formula. Symptoms that have been ascribed to formula intolerance fall into three general categories: unequivocal gastrointestinal symptoms (bloody stools, diarrhea, vomiting) that are pathophysiologically related to a specific formula component; unequivocal gastrointestinal symptoms that are more difficult to relate directly to the components of formula (excess flatus, cramps); and symptoms that may or may not have a primary gastrointestinal cause (fussiness, or colic) and are therefore far more difficult to relate to the formula.

The reported percentage of infants affected by formula intolerance varies widely—from less than 10% to greater than 30%—partly because agreement about the definition of this term is lacking. Formula intolerance in an otherwise normal infant has been blamed on protein digestibility (high curd tension), protein allergenicity, primary lactose intolerance, secondary lactose intolerance, and a reaction to iron. An understanding of certain principles related to intolerance are worth reviewing because, even though formula switching is common, it often fails to resolve symptoms—much to the frustration of the baby, the parents, and the physician.

True cow-milk protein allergenicity, as documented by a double-blind, placebo-controlled challenge, is present in less than 6% of the population.7 Yet some medical practices switch as many as 30% of their formula-fed infants to hypoallergenic formulas because of perceived or suspected protein allergy. Hypoallergenic formulas (discussed below) have been developed for babies with documented or strongly suspected protein allergy and should be used only in these infants.

Lactose intolerance. Primary lactose intolerance is exceedingly rare, affecting perhaps one in 10,000 infants. Secondary lactose intolerance, by contrast, is far more common and often accompanies protracted diarrheal disease. It appears that the lactase enzyme is vulnerable to damage because it is located at the villous tip, unlike sucrase, which is found deeper in the crypt. The villous tip is most likely to be denuded during infectious diarrhea, and the enzyme may take up to a week to recover fully. A low-lactose or lactose-free formula may reduce carbohydrate malabsorption (and subsequent exacerbation of diarrhea by an osmotic mechanism) during the illness.8

Iron intolerance? The role of iron in formula intolerance has been debated since iron-fortified formula was introduced in the late 1960s. The perceived intolerance of infants to iron stems from gastrointestinal symptoms reported by adult patients taking medicinal ferrous sulfate. Double-blind, placebo-controlled trials have repeatedly shown that symptoms such as colic, hard stools, diarrhea, and constipation are unrelated to the iron content of formula.9 Some parents do indeed report that their infants have symptoms suggesting intolerance when switched to iron-fortified formula after being fed with breast milk, but a myriad of other differences between the two sources of nutrition must be considered. The difference in protein digestibility, for example, may well account for a difference in tolerance.

The newest cow-milk– based formulas

Formula manufacturers have made many adjustments to cow-milk– based formula over the years with two goals in mind: to make a product that more closely resembles human milk and to address issues of intolerance raised by standard milk-based formulas. They also have developed formulas intended for toddlers.

Imitating human milk. This goal is laudable but unattainable. In theory, by carefully measuring all nutrients found in human milk, a template could be created for how cow milk should be modified. The inherent problem in this approach is that the content of human milk is not uniform. Moreover, many compounds (such as growth factors and antibodies) and live cells in human milk either cannot be sustained when cow milk is modified and processed or do not tolerate a prolonged stay on the shelf.

Formula manufacturers have therefore settled on a second approach: to try to improve the performance of infant formulas vis-à-vis human milk by adding ingredients to help prevent infection and promote brain development—just two of the many areas where human milk has a decided advantage over cow milk. As a result, formula makers have considered adding nucleotides, which enhance immune function via a mechanism that is not clearly understood, as well as long-chain polyunsaturated fatty acids (LCPUFAs), such as docosohexaenoic acid and arachidonic acid, which are thought to improve brain development.

To date, nucleotides have been added to some formulas, but there is little convincing evidence that this change has had a large effect on clinical infection rates. The FDA has not approved adding LCPUFAs to infant formulas (something European manufacturers have been doing since the early 1990s), even though more research has been conducted on LCPUFAs in the last five years than on any other nutrient in formula. The benefit of added LCPUFAs for the term infant remains equivocal.

The theoretical benefits of LCPUFAs are interesting and appear to be well reasoned. Breastfed infants are neurodevelopmentally more advanced than those fed formula, and many studies have documented that breastfed babies have a higher intelligence quotient and more advanced cognitive abilities.10,11 Electroretinograms and visual evoked responses indicate that processing in the brain is faster in infants fed human milk than in infants fed formula. It is unclear, however, whether these findings are caused by nutrients found in human milk, such as neurotropic growth factors and LCPUFAs, a specific maternal-child interaction during the act of breastfeeding, or a selection bias based on who chooses to breastfeed.

LCPUFAs in human, but not cow, milk are candidate molecules for inclusion in formula, although evidence is increasing that because a term infant can synthesize them shortly after birth, the molecules are not essential in the diet. Adding LCPUFAs to manufactured formulas appears to increase retinal processing speed to a point at which infants fed such formulas resemble the human-milk–fed infant with regard to retinal function.12 The positive effects appear to wash out over time, however, bringing into question whether LCPUFAs permanently alter the developing brain. This is a busy area of research and parents already seem to be aware of the effects of docosahexaenoic acid and other LCPUFAs and are asking their health-care practitioners about them.

Eliminating potential for intolerance. The three most common variations on cow-milk–based formula are hypoallergenic formulas, lactose-free formulas, and premature discharge formulas. These formulas address, respectively, the issues of milk-protein allergy, lactose intolerance, and the specific nutrient deficits of small preterm infants.

Hypoallergenic formulas (hydrolysates) rely on the finding that extensive hydrolysis of cow-milk protein (mostly casein) reduces the antigenicity of formula. The goal in manufacturing these formulas is to have 90% of the protein have a molecular weight less than 1,250 kilodaltons (kd). Evidence indicates that large molecular-weight proteins are responsible for an IgE–mediated allergic response to milk protein.13 Although both the large proteins and those with a molecular weight of less than 1,250 kd cross the intestinal barrier freely, the smaller proteins are far less antigenic than those that are larger.

Hydrolyzed casein formulas that meet the criteria for "hypoallergenic" have been effective in preventing protein allergy in susceptible infants, such as those with a strong family history of allergy, and in treating infants who have already been sensitized. A major downside of these formulas is cost; they may be three times as expensive as standard cow-milk–based or soy formulas. The low incidence of true cow-milk allergy, combined with the expense of these specialty formulas, means that meticulous diagnosis of cow-milk allergy, using a double-blind placebo-controlled challenge test, is critical to avoiding overprescribing these products. In such a test, the mother must not know which formula the baby is receiving as she documents signs and symptoms, such as fussiness, blood in the stool, or rash. The test is best performed under the close supervision of the physician because a severe allergic reaction to a formula is always a possibility. Table 1 compares three types of hydrolysate formulas: those based on the cow-milk proteins casein and whey and formulas based on amino acids.

 

TABLE 1
A look at hydrolysate formulas*

FeatureCasein hydrolysate formulaWhey hydrolysate formulaAmino acid formula
Fat sourceVegetable oils with medium-chain triglycerides**Vegetable oils without added medium-chain triglyceridesVegetable oils with 5% medium-chain triglycerides
Carbohydrate sourceModified corn or tapioca starch with or without sucrose; no lactoseLactose and corn maltodextrinCorn syrup solids; no lactose
Density (kcal/oz)202020
Concentration (g/L)18.816.222.3
SourceCasein hydrolysate with added L-cystine, L-tryptophan, and L-tyrosineWhey hydrolysateIndividual L-amino acids
Osmolarity304242308
Cost300%100%360%

 

Lactose-free cow-milk–based formulas are designed to treat infant feeding difficulties caused by lactose intolerance. They are designed primarily for use during secondary lactase deficiency, which typically lasts only a short time—typically less than a week. Studies to support claims that these formulas can be used to treat colic are unconvincing. The composition of these formulas is identical to lactose-containing cow-milk formulas, but instead of lactose, the carbohydrate source, as in soy-based formulas, is either corn syrup solids alone or corn syrup solids and sucrose.

The elimination of lactose in the infant diet has been a subject of intense research. Concerns have been raised that lactose is important as a trophic factor for normal gut development and for calcium absorption. Proponents of the need for lactose in the infant diet are worried about long-term use of lactose-free formulas, whether they are based on soy or cow milk. Infants fed soy protein-based formulas have normal bone mineralization, however, suggesting that the lactose-calcium interaction is not a major clinical concern.14 It is extremely important to recognize that lactose-free, cow-milk-based formulas do contain trace amounts of lactose and should not be used in conditions where lactose is strictly contraindicated, such as galactosemia. It remains unclear what role lactose-free, cow-milk–based formula has in infant nutrition other than to manage transient secondary lactase deficiency, which usually can be handled without switching formulas.

Premature discharge formulas have been modified to address specific postdischarge nutrient needs of infants born before 34 weeks' gestation. The nutritional goal for these infants is to achieve the size and bone mineral content of their term counterparts as rapidly as possible. The task is formidable because premature infants have accrued nutrient deficits and are extremely small when they leave the intensive care unit. Whereas the average term infant weighs 3.3 kg at 40 weeks postconception, most preterm infants are significantly growth retarded at a weight of between 2.0 and 2.5 kg.

To reach a target weight of 10 kg at 1 year of age, a term infant needs merely to triple his (or her) birth weight; a preterm infant, on the other hand, may need to quadruple or quintuple his weight at 40 weeks postconception. A preterm infant may leave the hospital with an estimated caloric deficit of 1,000 kcal/kg and a protein deficit of 25 g/kg.15 As many as two thirds of infants with a birth weight less than 1,500 g are demineralized at the time of discharge.16 Several studies have documented poor catch-up growth by premature infants in the first year after intensive care.17 Significant neurodevelopmental consequences have been documented when head growth is compromised by neonatal malnutrition.18

Premature discharge formulas were designed to compensate for these infants' nutritional deficits. They include a higher caloric density, protein content, and calcium and phosphorus content than standard formulas (Table 2), and have been shown to be more efficacious than standard term, cow-milk–based formula in promoting catch-up growth in the nine months after discharge.19 The formulas can be used safely for the entire first year of life. Infants who appear to benefit most from these formulas are in three categories: those with a birth weight less than 1,000 g; those who weigh less than 1,800 g at birth and are not achieving catch-up growth (defined as crossing percentiles); and those with an elevated alkaline phosphatase concentration at discharge. Premature discharge formulas also can be used to supplement breastfeeding in very low birth-weight premature infants after discharge. Typically, two formula feedings a day in addition to breast milk feedings can be used initially; the pediatrician can increase or decrease the number of formula feedings based on anthropometric and bone mineralization parameters.

 

TABLE 2
A comparison of formulas

ComponentCow-milk–based formula* (iron fortified)Premature discharge formulaSoy-based formula
Content48.5% fat/43% carbohydrate47% fat/42% carbohydrate47% fat/42% carbohydrate
ModificationsNoneMedium-chain triglyceride oil and glucose polymersCorn syrup solids + sucrose
Density (kcal/oz)202220
Delivery (kcal/kg/d)**100110100
SourceNonfat milk + wheyNonfat milk + wheySoy + L-methionine
Concentration (g/L)142017.5
Delivery (g/kg/d)**2.13.02.6
Concentration (mg/L)527/321843/480709/493
Delivery (mg/kg/d)**79/48126/72106/74
Calcium-phosphorus ratio1.6:11.75:11.43:1
Concentration (mg/L)11.51212
Delivery (mg/kg/d)**1.71.81.8
Concentration (IU/L)2,027/4053,455/5602,050/412
Delivery (IU/kg/d)**304/61520/84308/62

 

Formulas intended for toddlers (so-called follow-on formulas) also have been introduced. The AAP Committee on Nutrition does not believe that these formulas have any role in the nutrition of the healthy toddler at low risk of nutritional deficiency. Children should drink whole or 2% milk until the age of 2 years and skim or 1% milk thereafter. Juice should be consumed only in moderation.

Soy-based formulas

Soy-based formulas, available for nearly a century, have been used as a treatment for cow-milk–based formula intolerance since the 1920s. They are as effective as cow-milk– based formulas for promoting infant growth, bone mineralization, and neurodevelopment. The formulas are manufactured at an energy density of 20 cal/oz and were designed to deal with the two major intolerances to cow-milk–based formulas by changing the source of the protein and the carbohydrate. The protein source is a soy isolate supplemented with L-methionine, L-carnitine, and taurine. Corn syrup solids or combined corn syrup solids and sucrose are the carbohydrates. The formula is completely lactose free and is therefore indicated for infants with galactosemia.

In the past, mineral absorption with soy-based formulas was a concern because the phytates in soy bind divalent cations such as iron, calcium, and zinc in the intestinal lumen, reducing their bioavailability. Supplementation of soy formula with iron, zinc, and calcium has largely overcome these issues. Infants on soy formulas are as iron sufficient as infants fed iron-fortified cow-milk formula and have comparable bone mineralization and linear growth.14,20 Some observers are concerned about the phytoestrogens in soy formulas because these substances have the potential for hormonal actions at critical points in development. The AAP has noted that limited human data do not support these concerns.21

Soy-based formulas remain an acceptable alternative to cow-milk– based formulas in term infants. They are not indicated for preterm infants in a special-care nursery; use in this group has exacerbated an already demineralized skeletal status. Because most infants with a birth weight of less that 1,500 g leave the hospital significantly demineralized, soy-based formula also should not be used in the premature infant after discharge.

In addition to their routine use in term infants with no medical complications, soy-based formulas can be used in formula-fed infants whose parents want their children to adhere to a vegetarian diet. The formulas appear to be useful for treating primary or secondary lactase deficiency, although data on infants recovering from acute diarrheal illness are equivocal. While soy formulas shorten the duration of diarrhea and dietary failure compared with cow-milk–based formula, the final outcome, from a nutritional perspective, does not differ.1

Soy formulas have been used extensively in children with cow-milk allergy with varying success. The variability is probably caused by several factors: soy protein itself can be antigenic; the effects of soy protein differ, depending on whether the strategy is treatment or prevention of allergic disease; and cow-milk intolerance represents a wide gamut of pathophysiology, only some of which is IgE mediated. Any infant's response to soy formula greatly depends on the initial pathology seen with cow-milk–based formula.

Although soy protein is clearly antigenic, it is less allergenic than cow-milk protein in infants. The baseline rate of allergy to soy-based formula in low-risk infants is less than 1%—a rate less than one third the rate of allergy to cow-milk–based formula.22 Infants with IgE–mediated cow-milk allergy are likely to do well on soy-protein–based formula, and giving them this formula should be the first step in treatment. About 10% of infants allergic to cow milk (as proven by double-blind, placebo-controlled challenge) will also be allergic to soy, however, and will need to be treated with less antigenic formulas such as the hydrolysates.23

Infants with non-IgE–mediated immunologic reactions to cow-milk–based formula, particularly if they present with eosinophilic proctocolitis, enterocolitis, villous atrophy, or esophagitis, are also likely to respond poorly to soy-protein–based formula and should be treated with hydrolysates. Given the low rate of true cow-milk allergy and non-IgE–mediated immunologic reactions, however, fewer than 1% of infants in any typical pediatric practice should receive either soy-based formula or a casein hydrolysate formula for treatment of these conditions.

Whereas the benefit of treating IgE–mediated cow-milk allergy by switching to soy formula is clear, little evidence exists to support a role for soy formula in preventing allergy in an infant at high risk based on family history.24 Breastfeeding significantly reduces the risk of later allergic disease, if provided exclusively and maintained long enough. The benefit apparently is conferred when the infant is kept away from potentially allergenic food through exclusive breastfeeding during the first six months of life, when the gut is particularly permeable to proteins. It is not surprising, therefore, that breastfed infants supplemented with soy-protein–based formula have atopic disease no less often at 2 years of age than infants supplemented with cow-milk–based formula.25

Soy-protein–based formula has also been proposed for treatment of colic. Placebo-controlled trials in which soy formula was compared with cow-milk formula have not supported this use.26

When it makes sense to switch

Formula switching is based on many scientific and nonscientific factors. Ultimately, parents make the decision to switch, but the physician can influence them by providing education and empathy. From a medical standpoint, a recommendation to switch formulas should be based on a risk-benefit assessment. Some switches—from standard cow-milk formula to soy-based formula, for example—are relatively innocuous; others—from an iron-fortified formula to a low-iron formula, for example, present a significant medical liability for little gain. Switching from standard cow-milk formula to hydrolysate formula carries a financial, rather than medical, risk. Table 3 shows the potential risks and benefits of some of the more common switches.

 

TABLE 3
Risks and benefits of switching formulas

Initial dietNew dietBenefit of switchingRisk of switching
Human milkCow-milk–based standard formulaNoneLose benefits of human milk (anti-infective and and immunologic properties; relative protection from chronic childhood diseases; advanced neurodevelopment; and economic advantages including fewer lost maternal work days) Develop milk-protein allergy
Cow-milk–based standard formulaSoy-based formulaTreat IgE–mediated cow-milk allergy, lactase deficiency galactosemia Adequate for vegetariansNo apparent risk
Cow-milk–based standard formulaHydrolysate formulaTreat IgE– and non-IgE–mediated combined cow-milk and soy allergyIncur additional expense
Cow-milk–based standard formulaLow-iron cow-milk–based formulaNoneDevelop iron-deficiency anemia Impede neurodevelopment
Cow-milk–based standard formulaLactose-free cow-milk–based formulaProbably none that a soy-based formula would not provideNo apparent risk
Cow-milk–based standard formulaPremature postdischarge formulaImprove growth and bone mineralization in preterm infants born atNo apparent risk

 

Most pediatricians and parents recognize that babies, especially young ones, can often be fussy. Their fussiness is frequently thought to be related to feeding practices. Because babies spend much of their time feeding, it is not surprising that parents identify feeding intolerance as a source of the fussiness. Hence, a good history is crucial to optimizing the chances that a switch in diet will alter the infant's symptoms. Infants with gastrointestinal-specific symptoms such as diarrhea, constipation, blood in the stool, and excessive flatus are more likely to yield positive information during a workup and to benefit from a judicious switch of formula. Symptoms such as irritability and colic, on the other hand, may or may not point to gastrointestinal pathology and are less likely than gastrointestinal-specific symptoms to be amenable to a change in diet.

A prudent pediatrician must be sure that parents have reasonable expectations and a rudimentary understanding of why formula switches are likely or unlikely to work. In addition to performing a good history and physical examination, therefore, discuss the risks of switching, such as failure to alleviate symptoms, medical complications, and financial impact.

Most pediatricians recognize the pitfalls in assessing whether an infant would benefit from a formula switch. Faced with a frustrated mother and fussy baby, however, it is tempting simply to change the formula and hope for the best. Yet an unsuccessful change of formula in such an infant frequently leads to a dissatisfied patient and frustrated parents (see "How to discourage unnecessary formula changes" below). And when an infant's symptoms abate after a change of formula, the switch frequently receives more credit than it deserves for alleviating an infant's symptoms: The benefit may not be related to the switch but to spontaneous resolution of an unrelated problem.

Breast is still best, but...

The vast majority of formula-fed infants tolerate cow-milk–based formula (see "Making a choice"). When parents want to switch their baby to another formula—a common practice triggered by relatively nonspecific symptoms—carefully weigh the risks and benefits of a change before supporting their request. Most important, convey clearly and loudly to mothers that breastfeeding is the preferred method for feeding human infants. Infant formulas are safe and nutritionally adequate, but they do not confer certain health benefits of human milk.

1. American Academy of Pediatrics: Breastfeeding and the use of human milk. Pediatrics 1997;100:1035

2. Chan GM: Growth and bone mineral status of discharged very-low birth weight infants fed different formulas or human milk. J Pediatr 1993;123:439

3. Composition of Feedings for Infants and Young Children. Ross Ready Reference. Columbus, Ohio, Abbott Laboratories, 1999

4. American Academy of Pediatrics: Iron Fortification of Infant Formulas. Pediatrics 1999;104:119

5. Lozoff B, Jimenez E, Wolf AW: Long-term developmental outcome of infants with iron deficiency. N Engl J Med 1991;325:687

6. Pizarro F, Yip R, Dallman PR, et al: Iron status with different infant feeding regimens: Relevance to screening and prevention of iron deficiency. J Pediatr 1991;118:687

7. Schrander JJ, van den Bogart JP, Forget PP, et al: Cow's milk protein intolerance in infants under 1 year of age: A prospective epidemiological study. Eur J Pediatr 1993;152:640

8. Allen UP, McLeod K, Wang EEL: Cow milk versus soy based formula in milk and moderate diarrhea: A randomized, controlled trial. Acta Paediatrica 1994;83:183

9. Nelson SE, Ziegler EE, Copeland AM, et al: Lack of adverse reactions to iron-fortified formula. Pediatrics 1988;75:352

10. Morrow-Tlucak M, Haude RH, Ernhart CB: Breastfeeding and cognitive development in the first 2 years of life. Soc Sci Med 1988;26:635

11. Wang YS, Wu SY: The effect of exclusive breastfeeding on development and incidence of infection in infants. J Hum Lactation 1996;12:27

12. Uauy RD, Birch DG, Birch EE, et al: Efficacy of dietary omega-3 fatty acids on retinal function of very-low birth-weight neonates. Pediatr Res 1990;28:485

13. Oldaeus G, Bjorksten B, Einarsson R, et al: Antigenicity and allergenicity of cow milk hydrolysates intended for infant feeding. Pediatr Allergy Immunol 1991;4:1156

14. Mimouni F, Campaigne B, Neylan M: Bone mineralization in the first year of life in infants fed human milk, cow-milk formula, or soy-based formula. J Pediatr 1993;122:348

15. Embleton ND, Pang N, Perring J, et al: Systematic underfeeding of preterm infants on neonatal intensive care units. Pediatr Res 1999;45:281A

16. Koo WW, Tsang RC: Calcium, magnesium, phosphorus, and vitamin D, in RC Tsang, A Lucas, R Uauy, et al (eds): Nutritional Needs of the Preterm Infant. London, Williams and Wilkins, 1993, pp 135–155

17. Georgieff MK, Mills MM, Zempel CE, et al: Catch-up growth, body composition and body proportionality of infants one year after newborn intensive care. J Pediatr 1989;114:288

18. Georgieff MK, Hoffman JS, Pereira GR, et al: The effect of neonatal caloric deprivation on head growth and one-year developmental status in preterm infants. J Pediatr 1985;107:581

19. Carver JD, Wu PYK, Hall RT, et al: Growth of preterm infants fed NeoCare or Similac with Iron after hospital discharge. Pediatric Res 1997;41:229A

20. Hertrampf E: Bioavailability of iron in soy-based formula and its effect on iron nutriture in infancy. Pediatrics 1986;78:640

21. American Academy of Pediatrics: Soy protein-based formulas: Recommendations for use in infant feeding. Pediatrics 1998;101:148

22. Johnstone DE, Roghmann KJ: Recommendations for soy infant formula: A review of the literature and a survey of pediatric allergists. Pediatr Asthma Allergy Immunol 1993;7:77

23. Bock SA, Atkins FM: Patterns of food hypersensitivity during sixteen years of double-blind, placebo-controlled food challenges. J Pediatr 1990;117:561

24. Chandra RK, Singh G, Sidhara B: Effect of feeding whey hydrolysate, soy and conventional cow-milk formulas on incidence of atopic diseases in high-risk infants. Ann Allergy 1989;63:13

25. Bardare M, Vaccari A, Allievi E: Influence of dietary manipulation on incidence of atopic disease in infants at risk. Ann Allergy 1993;71:366

26. Thomas DW, McGilligan K, Eisenberg L, et al: Infantile colic and type of milk feeding. Am J Dis Child 1987;141:451

THE AUTHOR is professor of pediatrics and child development, University of Minnesota Medical School, Minneapolis. He has received speaker honoraria from Ross Labs and serves, unpaid, on advisory boards for Mead-Johnson and Carnation.

How to discourage unnecessary formula changes

Preemptive teaching about the vicissitudes of infant feeding patterns may be the most effective approach to minimizing formula switching. Let Mother know that babies exhibit many different feeding patterns, most of which do not signify a formula allergy or intolerance and do not respond to a change in formula. Have this conversation before the infant develops symptoms—ideally in the nursery before discharge. By using this approach, Mother will not think anything is wrong with the infant if he or she is fussy. At the same time, of course, you must be acutely aware of any real warning signs of protein allergy, lactose intolerance, or other problems that would respond to a judicious switch in formula. Here are other suggestions:

• In your early discussion with parents about how to feed their infants, stress that breast milk is by far the best choice for the infant and that you and your office or clinic are available to help solve lactation problems. Emphasize that the contraindications to breastfeeding are few and that it is unlikely that the baby needs to be switched to formula because of perceived intolerance to breast milk. The American Academy of Pediatrics has a new initiative on promoting breastfeeding. Visit their Web site (www.aap.org ) for details.

• If an infant shows signs or symptoms that do not suggest a medical problem but that might respond to a change in formula, suggest a one-month trial of any formula the mother chooses. Explain that the infant will go through a period of fussiness or irritability that might suggest formula intolerance but that this is likely a period of adjustment.

• Once parents have decided to switch formulas, take part in the choice by going over options with them and the likelihood that a particular formula will—or more likely, will not—achieve the desired effect. Once the baby is on the new formula, be sure to apply the one-month rule before making another change. Advise parents that switching formulas is not likely to alleviate their infant's symptoms. This will head off the impression that if they just keep looking they can find a magic formula to solve their problems.

• If the family has switched formula once and the change failed to relieve symptoms, counsel them to try a hydrolysate formula—but also warn them that, considering that symptoms are nonspecific, this is an expensive proposition that is not likely to work. If the hydrolysate formula does not relieve symptoms, suggest that they go back to the original formula—which is likely to be less expensive—and wait out the infant's problem.

The author is indebted to Dr. Dina Curran of Southdale Pediatrics, Edina, Minn., for her practical advice on counseling mothers.

Making a choice

• Most infants do well on standard cow-milk–based formulas. They contain adequate vitamins and minerals for infant needs and should be consumed in their iron-supplemented form.

• Soy-milk formulas can be used by vegetarian families, for infants with lactase deficiency, and for most infants with IgE–mediated cow-milk allergy. Soy formulas are as effective as cow-milk– based formulas for supporting infant growth and development.

• Hypoallergenic formulas are expensive and are probably overprescribed. Nevertheless, these hydrolysates are extremely effective for severe allergy, especially where cross-reactivity between milk protein and soy is present or when the infant has a non-IgE–mediated immune response to cow-milk formula.

• Premature discharge formulas represent a nutritional hybrid between highly modified premature infant and standard cow-milk formulas. They address the nutrient deficits accrued by the small preterm infant and promote better post-discharge growth and mineralization during the first year of life.

 

Michael Georgieff. Taking a rational approach to the choice of infant formula. Contemporary Pediatrics 2001;8:112.